osh/cmd_parse.py

OILS / osh / cmd_parse.py View on Github | oilshell.org

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1	# Copyright 2016 Andy Chu. All rights reserved.
2	# Licensed under the Apache License, Version 2.0 (the "License");
3	# you may not use this file except in compliance with the License.
4	# You may obtain a copy of the License at
5	#
6	# http://www.apache.org/licenses/LICENSE-2.0
7	"""
8	cmd_parse.py - Parse high level shell commands.
9	"""
10	from __future__ import print_function
11
12	from _devbuild.gen import grammar_nt
13	from _devbuild.gen.id_kind_asdl import Id, Id_t, Id_str, Kind, Kind_str
14	from _devbuild.gen.types_asdl import lex_mode_e, cmd_mode_e, cmd_mode_t
15	from _devbuild.gen.syntax_asdl import (
16	loc,
17	SourceLine,
18	source,
19	parse_result,
20	parse_result_t,
21	command,
22	command_t,
23	condition,
24	condition_t,
25	for_iter,
26	ArgList,
27	BraceGroup,
28	LiteralBlock,
29	CaseArm,
30	case_arg,
31	IfArm,
32	pat,
33	pat_t,
34	Redir,
35	redir_param,
36	redir_loc,
37	redir_loc_t,
38	word_e,
39	word_t,
40	CompoundWord,
41	Token,
42	word_part_e,
43	word_part_t,
44	rhs_word,
45	rhs_word_t,
46	sh_lhs,
47	sh_lhs_t,
48	AssignPair,
49	EnvPair,
50	ParsedAssignment,
51	assign_op_e,
52	NameType,
53	proc_sig,
54	proc_sig_e,
55	Proc,
56	Func,
57	)
58	from core import alloc
59	from core import error
60	from core.error import p_die
61	from core import ui
62	from frontend import consts
63	from frontend import lexer
64	from frontend import location
65	from frontend import match
66	from frontend import reader
67	from mycpp.mylib import log
68	from osh import braces
69	from osh import bool_parse
70	from osh import word_
71
72	from typing import Optional, List, Dict, Any, Tuple, cast, TYPE_CHECKING
73	if TYPE_CHECKING:
74	from core.alloc import Arena
75	from core import optview
76	from frontend.lexer import Lexer
77	from frontend.parse_lib import ParseContext, AliasesInFlight
78	from frontend.reader import _Reader
79	from osh.word_parse import WordParser
80
81	_ = Kind_str # for debug prints
82
83	TAB_CH = 9 # ord('\t')
84	SPACE_CH = 32 # ord(' ')
85
86
87	def _ReadHereLines(
88	line_reader, # type: _Reader
89	h, # type: Redir
90	delimiter, # type: str
91	):
92	# type: (...) -> Tuple[List[Tuple[SourceLine, int]], Tuple[SourceLine, int]]
93	# NOTE: We read all lines at once, instead of parsing line-by-line,
94	# because of cases like this:
95	# cat <<EOF
96	# 1 $(echo 2
97	# echo 3) 4
98	# EOF
99	here_lines = [] # type: List[Tuple[SourceLine, int]]
100	last_line = None # type: Tuple[SourceLine, int]
101	strip_leading_tabs = (h.op.id == Id.Redir_DLessDash)
102
103	while True:
104	src_line, unused_offset = line_reader.GetLine()
105
106	if src_line is None: # EOF
107	# An unterminated here doc is just a warning in bash. We make it
108	# fatal because we want to be strict, and because it causes problems
109	# reporting other errors.
110	# Attribute it to the << in <<EOF for now.
111	p_die("Couldn't find terminator for here doc that starts here",
112	h.op)
113
114	assert len(src_line.content) != 0 # None should be the empty line
115
116	line = src_line.content
117
118	# If op is <<-, strip off ALL leading tabs -- not spaces, and not just
119	# the first tab.
120	start_offset = 0
121	if strip_leading_tabs:
122	n = len(line)
123	i = 0 # used after loop exit
124	while i < n:
125	if line[i] != '\t':
126	break
127	i += 1
128	start_offset = i
129
130	if line[start_offset:].rstrip() == delimiter:
131	last_line = (src_line, start_offset)
132	break
133
134	here_lines.append((src_line, start_offset))
135
136	return here_lines, last_line
137
138
139	def _MakeLiteralHereLines(
140	here_lines, # type: List[Tuple[SourceLine, int]]
141	arena, # type: Arena
142	do_lossless, # type: bool
143	):
144	# type: (...) -> List[word_part_t]
145	"""Create a Token for each line.
146
147	For <<'EOF' and <<-'EOF' - single quoted rule
148
149	<<- has non-zero start_offset
150	"""
151	# less precise type, because List[T] is an invariant type
152	tokens = [] # type: List[word_part_t]
153	for src_line, start_offset in here_lines:
154
155	# Maintain lossless invariant for STRIPPED tabs: add a Token to the
156	# arena invariant, but don't refer to it.
157	#
158	# Note: We could use Lit_CharsWithoutPrefix for 'single quoted' EOF
159	# here docs, but it's more complex with double quoted EOF docs.
160
161	if do_lossless: # avoid garbage, doesn't affect correctness
162	arena.NewToken(Id.Lit_CharsWithoutPrefix, start_offset, 0,
163	src_line)
164
165	t = arena.NewToken(Id.Lit_Chars, start_offset, len(src_line.content),
166	src_line)
167	tokens.append(t)
168	return tokens
169
170
171	def _ParseHereDocBody(parse_ctx, r, line_reader, arena):
172	# type: (ParseContext, Redir, _Reader, Arena) -> None
173	"""Fill in attributes of a pending here doc node."""
174	h = cast(redir_param.HereDoc, r.arg)
175	# "If any character in word is quoted, the delimiter shall be formed by
176	# performing quote removal on word, and the here-document lines shall not
177	# be expanded. Otherwise, the delimiter shall be the word itself."
178	# NOTE: \EOF counts, or even E\OF
179	ok, delimiter, delim_quoted = word_.StaticEval(h.here_begin)
180	if not ok:
181	p_die('Invalid here doc delimiter', loc.Word(h.here_begin))
182
183	here_lines, last_line = _ReadHereLines(line_reader, r, delimiter)
184
185	if delim_quoted:
186	# <<'EOF' and <<-'EOF' - Literal for each line.
187	h.stdin_parts = _MakeLiteralHereLines(here_lines, arena,
188	parse_ctx.do_lossless)
189	else:
190	# <<EOF and <<-EOF - Parse as word
191	line_reader = reader.VirtualLineReader(arena, here_lines,
192	parse_ctx.do_lossless)
193	w_parser = parse_ctx.MakeWordParserForHereDoc(line_reader)
194	w_parser.ReadHereDocBody(h.stdin_parts) # fills this in
195
196	end_line, start_offset = last_line
197
198	# Maintain lossless invariant for STRIPPED tabs: add a Token to the
199	# arena invariant, but don't refer to it.
200	if parse_ctx.do_lossless: # avoid garbage, doesn't affect correctness
201	arena.NewToken(Id.Lit_CharsWithoutPrefix, start_offset, 0, end_line)
202
203	# Create a Token with the end terminator. Maintains the invariant that the
204	# tokens "add up".
205	h.here_end_tok = arena.NewToken(Id.Undefined_Tok, start_offset,
206	len(end_line.content), end_line)
207
208
209	def _MakeAssignPair(parse_ctx, preparsed, arena):
210	# type: (ParseContext, ParsedAssignment, Arena) -> AssignPair
211	"""Create an AssignPair from a 4-tuples from DetectShAssignment."""
212
213	left_token = preparsed.left
214	close_token = preparsed.close
215
216	lhs = None # type: sh_lhs_t
217
218	if left_token.id == Id.Lit_VarLike: # s=1
219	if lexer.IsPlusEquals(left_token):
220	var_name = lexer.TokenSliceRight(left_token, -2)
221	op = assign_op_e.PlusEqual
222	else:
223	var_name = lexer.TokenSliceRight(left_token, -1)
224	op = assign_op_e.Equal
225
226	lhs = sh_lhs.Name(left_token, var_name)
227
228	elif left_token.id == Id.Lit_ArrayLhsOpen and parse_ctx.do_lossless:
229	var_name = lexer.TokenSliceRight(left_token, -1)
230	if lexer.IsPlusEquals(close_token):
231	op = assign_op_e.PlusEqual
232	else:
233	op = assign_op_e.Equal
234
235	assert left_token.line == close_token.line, \
236	'%s and %s not on same line' % (left_token, close_token)
237
238	left_pos = left_token.col + left_token.length
239	index_str = left_token.line.content[left_pos:close_token.col]
240	lhs = sh_lhs.UnparsedIndex(left_token, var_name, index_str)
241
242	elif left_token.id == Id.Lit_ArrayLhsOpen: # a[x++]=1
243	var_name = lexer.TokenSliceRight(left_token, -1)
244	if lexer.IsPlusEquals(close_token):
245	op = assign_op_e.PlusEqual
246	else:
247	op = assign_op_e.Equal
248
249	# Similar to SnipCodeString / SnipCodeBlock
250	if left_token.line == close_token.line:
251	# extract what's between brackets
252	s = left_token.col + left_token.length
253	code_str = left_token.line.content[s:close_token.col]
254	else:
255	raise NotImplementedError('%s != %s' %
256	(left_token.line, close_token.line))
257	a_parser = parse_ctx.MakeArithParser(code_str)
258
259	# a[i+1]= is a LHS
260	src = source.Reparsed('array LHS', left_token, close_token)
261	with alloc.ctx_SourceCode(arena, src):
262	index_node = a_parser.Parse() # may raise error.Parse
263
264	lhs = sh_lhs.IndexedName(left_token, var_name, index_node)
265
266	else:
267	raise AssertionError()
268
269	# TODO: Should we also create a rhs_expr.ArrayLiteral here?
270	parts = preparsed.w.parts
271	offset = preparsed.part_offset
272
273	n = len(parts)
274	if offset == n:
275	rhs = rhs_word.Empty # type: rhs_word_t
276	else:
277	w = CompoundWord(parts[offset:])
278	word_.TildeDetectAssign(w)
279	rhs = w
280
281	return AssignPair(left_token, lhs, op, rhs)
282
283
284	def _AppendMoreEnv(preparsed_list, more_env):
285	# type: (List[ParsedAssignment], List[EnvPair]) -> None
286	"""Helper to modify a SimpleCommand node.
287
288	Args:
289	preparsed: a list of 4-tuples from DetectShAssignment
290	more_env: a list to append env_pairs to
291	"""
292	for preparsed in preparsed_list:
293	left_token = preparsed.left
294
295	if left_token.id != Id.Lit_VarLike: # can't be a[x]=1
296	p_die(
297	"Environment binding shouldn't look like an array assignment",
298	left_token)
299
300	if lexer.IsPlusEquals(left_token):
301	p_die('Expected = in environment binding, got +=', left_token)
302
303	var_name = lexer.TokenSliceRight(left_token, -1)
304
305	parts = preparsed.w.parts
306	n = len(parts)
307	offset = preparsed.part_offset
308	if offset == n:
309	rhs = rhs_word.Empty # type: rhs_word_t
310	else:
311	w = CompoundWord(parts[offset:])
312	word_.TildeDetectAssign(w)
313	rhs = w
314
315	more_env.append(EnvPair(left_token, var_name, rhs))
316
317
318	def _SplitSimpleCommandPrefix(words):
319	# type: (List[CompoundWord]) -> Tuple[List[ParsedAssignment], List[CompoundWord]]
320	"""Second pass of SimpleCommand parsing: look for assignment words."""
321	preparsed_list = [] # type: List[ParsedAssignment]
322	suffix_words = [] # type: List[CompoundWord]
323
324	done_prefix = False
325	for w in words:
326	if done_prefix:
327	suffix_words.append(w)
328	continue
329
330	left_token, close_token, part_offset = word_.DetectShAssignment(w)
331	if left_token:
332	preparsed_list.append(
333	ParsedAssignment(left_token, close_token, part_offset, w))
334	else:
335	done_prefix = True
336	suffix_words.append(w)
337
338	return preparsed_list, suffix_words
339
340
341	def _MakeSimpleCommand(
342	preparsed_list, # type: List[ParsedAssignment]
343	suffix_words, # type: List[CompoundWord]
344	typed_args, # type: Optional[ArgList]
345	block, # type: Optional[LiteralBlock]
346	):
347	# type: (...) -> command.Simple
348	"""Create a command.Simple"""
349
350	# FOO=(1 2 3) ls is not allowed.
351	for preparsed in preparsed_list:
352	if word_.HasArrayPart(preparsed.w):
353	p_die("Environment bindings can't contain array literals",
354	loc.Word(preparsed.w))
355
356	# NOTE: It would be possible to add this check back. But it already happens
357	# at runtime in EvalWordSequence2.
358	# echo FOO=(1 2 3) is not allowed (but we should NOT fail on echo FOO[x]=1).
359	if 0:
360	for w in suffix_words:
361	if word_.HasArrayPart(w):
362	p_die("Commands can't contain array literals", loc.Word(w))
363
364	assert len(suffix_words) != 0
365	# {a,b,c} # Use { before brace detection
366	# ~/bin/ls # Use ~ before tilde detection
367	part0 = suffix_words[0].parts[0]
368	blame_tok = location.LeftTokenForWordPart(part0)
369
370	# NOTE: We only do brace DETECTION here, not brace EXPANSION. Therefore we
371	# can't implement bash's behavior of having say {~bob,~jane}/src work,
372	# because we only have a BracedTree.
373	# This is documented in spec/brace-expansion.
374	# NOTE: Technically we could do expansion outside of 'oshc translate', but it
375	# doesn't seem worth it.
376	words2 = braces.BraceDetectAll(suffix_words)
377	words3 = word_.TildeDetectAll(words2)
378
379	more_env = [] # type: List[EnvPair]
380	_AppendMoreEnv(preparsed_list, more_env)
381
382	# do_fork by default
383	return command.Simple(blame_tok, more_env, words3, typed_args, block, True)
384
385
386	class VarChecker(object):
387	"""Statically check for proc and variable usage errors."""
388
389	def __init__(self):
390	# type: () -> None
391	"""
392	Args:
393	oil_proc: Whether to disallow nested proc/function declarations
394	"""
395	# self.tokens for location info: 'proc' or another token
396	self.tokens = [] # type: List[Token]
397	self.names = [] # type: List[Dict[str, Id_t]]
398
399	def Push(self, blame_tok):
400	# type: (Token) -> None
401	"""Called when we enter a shell function, proc, or func.
402
403	Bash allows this, but it's confusing because it's the same as two
404	functions at the top level.
405
406	f() {
407	g() {
408	echo 'top level function defined in another one'
409	}
410	}
411
412	YSH disallows nested procs and funcs.
413	"""
414	if len(self.tokens) != 0:
415	if blame_tok.id == Id.KW_Proc:
416	p_die("procs must be defined at the top level", blame_tok)
417	if blame_tok.id == Id.KW_Func:
418	p_die("funcs must be defined at the top level", blame_tok)
419	if self.tokens[0].id in (Id.KW_Proc, Id.KW_Func):
420	p_die("shell functions can't be defined inside proc or func",
421	blame_tok)
422
423	self.tokens.append(blame_tok)
424	entry = {} # type: Dict[str, Id_t]
425	self.names.append(entry)
426
427	def Pop(self):
428	# type: () -> None
429	self.names.pop()
430	self.tokens.pop()
431
432	def Check(self, keyword_id, var_name, blame_tok):
433	# type: (Id_t, str, Token) -> None
434	"""Check for declaration / mutation errors in proc and func.
435
436	var x
437	x already declared
438	setvar x:
439	x is not declared
440	setglobal x:
441	No errors are possible; we would need all these many conditions to
442	statically know the names:
443	- no 'source'
444	- shopt -u copy_env.
445	- AND use lib has to be static
446
447	What about bare assignment in Hay? I think these are dynamic checks --
448	there is no static check. Hay is for building up data imperatively,
449	and then LATER, right before main(), it can be type checked.
450
451	Package {
452	version = '3.11'
453	version = '3.12'
454	}
455	"""
456	# No static checks are the global level! Because of 'source', var and
457	# setvar are essentially the same.
458	if len(self.names) == 0:
459	return
460
461	top = self.names[-1]
462	if keyword_id == Id.KW_Var:
463	if var_name in top:
464	p_die('%r was already declared' % var_name, blame_tok)
465	else:
466	top[var_name] = keyword_id
467
468	if keyword_id == Id.KW_SetVar:
469	if var_name not in top:
470	# Note: the solution could be setglobal, etc.
471	p_die(
472	"setvar couldn't find matching 'var %s' (OILS-ERR-10)" %
473	var_name, blame_tok)
474
475
476	class ctx_VarChecker(object):
477
478	def __init__(self, var_checker, blame_tok):
479	# type: (VarChecker, Token) -> None
480	var_checker.Push(blame_tok)
481	self.var_checker = var_checker
482
483	def __enter__(self):
484	# type: () -> None
485	pass
486
487	def __exit__(self, type, value, traceback):
488	# type: (Any, Any, Any) -> None
489	self.var_checker.Pop()
490
491
492	class ctx_CmdMode(object):
493
494	def __init__(self, cmd_parse, new_cmd_mode):
495	# type: (CommandParser, cmd_mode_t) -> None
496	self.cmd_parse = cmd_parse
497	self.prev_cmd_mode = cmd_parse.cmd_mode
498	cmd_parse.cmd_mode = new_cmd_mode
499
500	def __enter__(self):
501	# type: () -> None
502	pass
503
504	def __exit__(self, type, value, traceback):
505	# type: (Any, Any, Any) -> None
506	self.cmd_parse.cmd_mode = self.prev_cmd_mode
507
508
509	SECONDARY_KEYWORDS = [
510	Id.KW_Do, Id.KW_Done, Id.KW_Then, Id.KW_Fi, Id.KW_Elif, Id.KW_Else,
511	Id.KW_Esac
512	]
513
514
515	class CommandParser(object):
516	"""Recursive descent parser derived from POSIX shell grammar.
517
518	This is a BNF grammar:
519	https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_10
520
521	- Augmented with both bash/OSH and YSH constructs.
522
523	- We use regex-like iteration rather than recursive references
524	? means optional (0 or 1)
525	* means 0 or more
526	+ means 1 or more
527
528	- Keywords are spelled in Caps:
529	If Elif Case
530
531	- Operator tokens are quoted:
532	'(' '\|'
533
534	or can be spelled directly if it matters:
535
536	Op_LParen Op_Pipe
537
538	- Non-terminals are snake_case:
539	brace_group subshell
540
541	Methods in this class should ROUGHLY CORRESPOND to grammar productions, and
542	the production should be in the method docstrings, e.g.
543
544	def ParseSubshell():
545	"
546	subshell : '(' compound_list ')'
547
548	Looking at Op_LParen # Comment to say how this method is called
549	"
550
551	The grammar may be factored to make parsing easier.
552	"""
553
554	def __init__(self,
555	parse_ctx,
556	parse_opts,
557	w_parser,
558	lexer,
559	line_reader,
560	eof_id=Id.Eof_Real):
561	# type: (ParseContext, optview.Parse, WordParser, Lexer, _Reader, Id_t) -> None
562	self.parse_ctx = parse_ctx
563	self.aliases = parse_ctx.aliases # aliases to expand at parse time
564
565	self.parse_opts = parse_opts
566	self.w_parser = w_parser # type: WordParser # for normal parsing
567	self.lexer = lexer # for pushing hints, lookahead to (
568	self.line_reader = line_reader # for here docs
569	self.eof_id = eof_id
570
571	self.arena = line_reader.arena # for adding here doc and alias spans
572	self.aliases_in_flight = [] # type: AliasesInFlight
573
574	# A hacky boolean to remove 'if cd / {' ambiguity.
575	self.allow_block = True
576
577	# Stack of booleans for nested Attr and SHELL nodes.
578	# Attr nodes allow bare assignment x = 42, but not shell x=42.
579	# SHELL nodes are the inverse. 'var x = 42' is preferred in shell
580	# nodes, but x42 is still allowed.
581	#
582	# Note: this stack could be optimized by turning it into an integer and
583	# binary encoding.
584	self.hay_attrs_stack = [] # type: List[bool]
585
586	# Note: VarChecker is instantiated with each CommandParser, which means
587	# that two 'proc foo' -- inside a command sub and outside -- don't
588	# conflict, because they use different CommandParser instances. I think
589	# this OK but you can imagine different behaviors.
590	self.var_checker = VarChecker()
591
592	self.cmd_mode = cmd_mode_e.Shell # type: cmd_mode_t
593
594	self.Reset()
595
596	# Init_() function for "keyword arg"
597	def Init_AliasesInFlight(self, aliases_in_flight):
598	# type: (AliasesInFlight) -> None
599	self.aliases_in_flight = aliases_in_flight
600
601	def Reset(self):
602	# type: () -> None
603	"""Reset our own internal state.
604
605	Called by the interactive loop.
606	"""
607	# Cursor state set by _GetWord()
608	self.next_lex_mode = lex_mode_e.ShCommand
609	self.cur_word = None # type: word_t # current word
610	self.c_kind = Kind.Undefined
611	self.c_id = Id.Undefined_Tok
612
613	self.pending_here_docs = [] # type: List[Redir]
614
615	def ResetInputObjects(self):
616	# type: () -> None
617	"""Reset the internal state of our inputs.
618
619	Called by the interactive loop.
620	"""
621	self.w_parser.Reset()
622	self.lexer.ResetInputObjects()
623	self.line_reader.Reset()
624
625	def _SetNext(self):
626	# type: () -> None
627	"""Call this when you no longer need the current token.
628
629	This method is lazy. A subsequent call to _GetWord() will
630	actually read the next Token.
631	"""
632	self.next_lex_mode = lex_mode_e.ShCommand
633
634	def _SetNextBrack(self):
635	# type: () -> None
636	self.next_lex_mode = lex_mode_e.ShCommandFakeBrack
637
638	def _GetWord(self):
639	# type: () -> None
640	"""Call this when you need to make a decision based on Id or Kind.
641
642	If there was an "unfulfilled" call to _SetNext(), it reads a word and sets
643	self.c_id and self.c_kind.
644
645	Otherwise it does nothing.
646	"""
647	if self.next_lex_mode != lex_mode_e.Undefined:
648	w = self.w_parser.ReadWord(self.next_lex_mode)
649	#log("w %s", w)
650
651	# Here docs only happen in command mode, so other kinds of newlines don't
652	# count.
653	if w.tag() == word_e.Operator:
654	tok = cast(Token, w)
655	if tok.id == Id.Op_Newline:
656	for h in self.pending_here_docs:
657	_ParseHereDocBody(self.parse_ctx, h, self.line_reader,
658	self.arena)
659	del self.pending_here_docs[:] # No .clear() until Python 3.3.
660
661	self.cur_word = w
662
663	self.c_kind = word_.CommandKind(self.cur_word)
664	# Has special case for Id.Lit_{LBrace,RBrace,Equals}
665	self.c_id = word_.CommandId(self.cur_word)
666	self.next_lex_mode = lex_mode_e.Undefined
667
668	def _Eat(self, c_id, msg=None):
669	# type: (Id_t, Optional[str]) -> word_t
670	"""Consume a word of a type, maybe showing a custom error message.
671
672	Args:
673	c_id: the Id we expected
674	msg: improved error message
675	"""
676	self._GetWord()
677	if self.c_id != c_id:
678	if msg is None:
679	msg = 'Expected word type %s, got %s' % (
680	ui.PrettyId(c_id), ui.PrettyId(self.c_id))
681	p_die(msg, loc.Word(self.cur_word))
682
683	skipped = self.cur_word
684	self._SetNext()
685	return skipped
686
687	def _NewlineOk(self):
688	# type: () -> None
689	"""Check for optional newline and consume it."""
690	self._GetWord()
691	if self.c_id == Id.Op_Newline:
692	self._SetNext()
693
694	def _AtSecondaryKeyword(self):
695	# type: () -> bool
696	self._GetWord()
697	if self.c_id in SECONDARY_KEYWORDS:
698	return True
699	return False
700
701	def ParseRedirect(self):
702	# type: () -> Redir
703	self._GetWord()
704	assert self.c_kind == Kind.Redir, self.cur_word
705	op_tok = cast(Token, self.cur_word) # for MyPy
706
707	# Note: the lexer could take distinguish between
708	# >out
709	# 3>out
710	# {fd}>out
711	#
712	# which would make the code below faster. But small string optimization
713	# would also speed it up, since redirects are small.
714
715	# One way to do this is with Kind.Redir and Kind.RedirNamed, and then
716	# possibly "unify" the IDs by subtracting a constant like 8 or 16?
717
718	op_val = lexer.TokenVal(op_tok)
719	if op_val[0] == '{':
720	pos = op_val.find('}')
721	assert pos != -1 # lexer ensures this
722	where = redir_loc.VarName(op_val[1:pos]) # type: redir_loc_t
723
724	elif op_val[0].isdigit():
725	pos = 1
726	if op_val[1].isdigit():
727	pos = 2
728	where = redir_loc.Fd(int(op_val[:pos]))
729
730	else:
731	where = redir_loc.Fd(consts.RedirDefaultFd(op_tok.id))
732
733	self._SetNext()
734
735	self._GetWord()
736	# Other redirect
737	if self.c_kind != Kind.Word:
738	p_die('Invalid token after redirect operator',
739	loc.Word(self.cur_word))
740
741	# Here doc
742	if op_tok.id in (Id.Redir_DLess, Id.Redir_DLessDash):
743	arg = redir_param.HereDoc.CreateNull()
744	arg.here_begin = self.cur_word
745	arg.stdin_parts = []
746
747	r = Redir(op_tok, where, arg)
748
749	self.pending_here_docs.append(r) # will be filled on next newline.
750
751	self._SetNext()
752	return r
753
754	arg_word = self.cur_word
755	tilde = word_.TildeDetect(arg_word)
756	if tilde:
757	arg_word = tilde
758	self._SetNext()
759
760	# We should never get Empty, Token, etc.
761	assert arg_word.tag() == word_e.Compound, arg_word
762	return Redir(op_tok, where, cast(CompoundWord, arg_word))
763
764	def _ParseRedirectList(self):
765	# type: () -> List[Redir]
766	"""Try parsing any redirects at the cursor.
767
768	This is used for blocks only, not commands.
769	"""
770	redirects = [] # type: List[Redir]
771	while True:
772	# This prediction needs to ONLY accept redirect operators. Should we
773	# make them a separate Kind?
774	self._GetWord()
775	if self.c_kind != Kind.Redir:
776	break
777
778	node = self.ParseRedirect()
779	redirects.append(node)
780	self._SetNext()
781
782	return redirects
783
784	def _MaybeParseRedirectList(self, node):
785	# type: (command_t) -> command_t
786	"""Try parsing redirects at the current position.
787
788	If there are any, then wrap the command_t argument with a
789	command.Redirect node. Otherwise, return argument unchanged.
790	"""
791	self._GetWord()
792	if self.c_kind != Kind.Redir:
793	return node
794
795	redirects = [self.ParseRedirect()]
796
797	while True:
798	# This prediction needs to ONLY accept redirect operators. Should we
799	# make them a separate Kind?
800	self._GetWord()
801	if self.c_kind != Kind.Redir:
802	break
803
804	redirects.append(self.ParseRedirect())
805	self._SetNext()
806
807	return command.Redirect(node, redirects)
808
809	def _ScanSimpleCommand(self):
810	# type: () -> Tuple[List[Redir], List[CompoundWord], Optional[ArgList], Optional[LiteralBlock]]
811	"""YSH extends simple commands with typed args and blocks.
812
813	Shell has a recursive grammar, which awkwardly expresses
814	non-grammatical rules:
815
816	simple_command : cmd_prefix cmd_word cmd_suffix
817	\| cmd_prefix cmd_word
818	\| cmd_prefix
819	\| cmd_name cmd_suffix
820	\| cmd_name
821	;
822	cmd_name : WORD /* Apply rule 7a */
823	;
824	cmd_word : WORD /* Apply rule 7b */
825	;
826	cmd_prefix : io_redirect
827	\| cmd_prefix io_redirect
828	\| ASSIGNMENT_WORD
829	\| cmd_prefix ASSIGNMENT_WORD
830	;
831	cmd_suffix : io_redirect
832	\| cmd_suffix io_redirect
833	\| WORD
834	\| cmd_suffix WORD
835
836	YSH grammar:
837
838	redirect = redir_op WORD
839	item = WORD \| redirect
840
841	typed_args =
842	'(' arglist ')'
843	\| '[' arglist ']'
844
845	simple_command =
846	cmd_prefix* item+ typed_args? BraceGroup? cmd_suffix*
847
848	Notably, redirects shouldn't appear after typed args, or after
849	BraceGroup.
850
851	Examples:
852
853	This is an assignment:
854	foo=1 >out
855
856	This is a command.Simple
857	>out
858
859	What about
860	>out (42)
861	"""
862	redirects = [] # type: List[Redir]
863	words = [] # type: List[CompoundWord]
864	typed_args = None # type: Optional[ArgList]
865	block = None # type: Optional[LiteralBlock]
866
867	first_word_caps = False # does first word look like Caps, but not CAPS
868
869	i = 0
870	while True:
871	self._GetWord()
872
873	# If we got { }, change it to something that's not Kind.Word
874	kind2 = self.c_kind
875	if (kind2 == Kind.Word and self.parse_opts.parse_brace() and
876	self.c_id in (Id.Lit_LBrace, Id.Lit_RBrace)):
877	kind2 = Kind.Op
878
879	if kind2 == Kind.Redir:
880	node = self.ParseRedirect()
881	redirects.append(node)
882
883	elif kind2 == Kind.Word:
884	w = cast(CompoundWord, self.cur_word) # Kind.Word ensures this
885
886	if i == 0:
887	# Disallow leading =a because it's confusing
888	part0 = w.parts[0]
889	if part0.tag() == word_part_e.Literal:
890	tok = cast(Token, part0)
891	if tok.id == Id.Lit_Equals:
892	p_die(
893	"=word isn't allowed. Hint: add a space after =, or quote it",
894	tok)
895
896	# Is the first word a Hay Attr word?
897	#
898	# Can we remove this StaticEval() call, and just look
899	# inside Token? I think once we get rid of SHELL nodes,
900	# this will be simpler.
901
902	ok, word_str, quoted = word_.StaticEval(w)
903	# Foo { a = 1 } is OK, but not foo { a = 1 } or FOO { a = 1 }
904	if (ok and len(word_str) and word_str[0].isupper() and
905	not word_str.isupper()):
906	first_word_caps = True
907	#log('W %s', word_str)
908
909	words.append(w)
910
911	else:
912	break
913
914	self._SetNextBrack() # Allow bracket for SECOND word on
915	i += 1
916
917	# my-cmd (x) or my-cmd [x]
918	self._GetWord()
919	if self.c_id == Id.Op_LParen:
920	# 1. Check that there's a preceding space
921	prev_byte = self.lexer.ByteLookBack()
922	if prev_byte not in (SPACE_CH, TAB_CH):
923	if self.parse_opts.parse_at():
924	p_die('Space required before (', loc.Word(self.cur_word))
925	else:
926	# inline func call like @sorted(x) is invalid in OSH, but the
927	# solution isn't a space
928	p_die(
929	'Unexpected left paren (might need a space before it)',
930	loc.Word(self.cur_word))
931
932	# 2. Check that it's not (). We disallow this because it's a no-op and
933	# there could be confusion with shell func defs.
934	# For some reason we need to call lexer.LookPastSpace, not
935	# w_parser.LookPastSpace. I think this is because we're at (, which is
936	# an operator token. All the other cases are like 'x=', which is PART
937	# of a word, and we don't know if it will end.
938	next_id = self.lexer.LookPastSpace(lex_mode_e.ShCommand)
939	if next_id == Id.Op_RParen:
940	p_die('Empty arg list not allowed', loc.Word(self.cur_word))
941
942	typed_args = self.w_parser.ParseProcCallArgs(
943	grammar_nt.ysh_eager_arglist)
944
945	self._SetNext()
946
947	elif self.c_id == Id.Op_LBracket: # only when parse_bracket set
948	typed_args = self.w_parser.ParseProcCallArgs(
949	grammar_nt.ysh_lazy_arglist)
950
951	self._SetNext()
952
953	self._GetWord()
954
955	# Allow redirects after typed args, e.g.
956	# json write (x) > out.txt
957	if self.c_kind == Kind.Redir:
958	redirects.extend(self._ParseRedirectList())
959
960	# my-cmd { echo hi } my-cmd (x) { echo hi } ...
961	if (self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace and
962	# Disabled for if/while condition, etc.
963	self.allow_block):
964
965	# allow x = 42
966	self.hay_attrs_stack.append(first_word_caps)
967	brace_group = self.ParseBraceGroup()
968
969	# So we can get the source code back later
970	lines = self.arena.SaveLinesAndDiscard(brace_group.left,
971	brace_group.right)
972	block = LiteralBlock(brace_group, lines)
973
974	self.hay_attrs_stack.pop()
975
976	self._GetWord()
977
978	# Allow redirects after block, e.g.
979	# cd /tmp { echo $PWD } > out.txt
980	if self.c_kind == Kind.Redir:
981	redirects.extend(self._ParseRedirectList())
982
983	return redirects, words, typed_args, block
984
985	def _MaybeExpandAliases(self, words):
986	# type: (List[CompoundWord]) -> Optional[command_t]
987	"""Try to expand aliases.
988
989	Args:
990	words: A list of Compound
991
992	Returns:
993	A new LST node, or None.
994
995	Our implementation of alias has two design choices:
996	- Where to insert it in parsing. We do it at the end of ParseSimpleCommand.
997	- What grammar rule to parse the expanded alias buffer with. In our case
998	it's ParseCommand().
999
1000	This doesn't quite match what other shells do, but I can't figure out a
1001	better places.
1002
1003	Most test cases pass, except for ones like:
1004
1005	alias LBRACE='{'
1006	LBRACE echo one; echo two; }
1007
1008	alias MULTILINE='echo 1
1009	echo 2
1010	echo 3'
1011	MULTILINE
1012
1013	NOTE: dash handles aliases in a totally different way. It has a global
1014	variable checkkwd in parser.c. It assigns it all over the grammar, like
1015	this:
1016
1017	checkkwd = CHKNL \| CHKKWD \| CHKALIAS;
1018
1019	The readtoken() function checks (checkkwd & CHKALIAS) and then calls
1020	lookupalias(). This seems to provide a consistent behavior among shells,
1021	but it's less modular and testable.
1022
1023	Bash also uses a global 'parser_state & PST_ALEXPNEXT'.
1024
1025	Returns:
1026	A command node if any aliases were expanded, or None otherwise.
1027	"""
1028	# Start a new list if there aren't any. This will be passed recursively
1029	# through CommandParser instances.
1030	aliases_in_flight = (self.aliases_in_flight
1031	if len(self.aliases_in_flight) else [])
1032
1033	# for error message
1034	first_word_str = None # type: Optional[str]
1035	argv0_loc = loc.Word(words[0])
1036
1037	expanded = [] # type: List[str]
1038	i = 0
1039	n = len(words)
1040
1041	while i < n:
1042	w = words[i]
1043
1044	ok, word_str, quoted = word_.StaticEval(w)
1045	if not ok or quoted:
1046	break
1047
1048	alias_exp = self.aliases.get(word_str)
1049	if alias_exp is None:
1050	break
1051
1052	# Prevent infinite loops. This is subtle: we want to prevent infinite
1053	# expansion of alias echo='echo x'. But we don't want to prevent
1054	# expansion of the second word in 'echo echo', so we add 'i' to
1055	# "aliases_in_flight".
1056	if (word_str, i) in aliases_in_flight:
1057	break
1058
1059	if i == 0:
1060	first_word_str = word_str # for error message
1061
1062	#log('%r -> %r', word_str, alias_exp)
1063	aliases_in_flight.append((word_str, i))
1064	expanded.append(alias_exp)
1065	i += 1
1066
1067	if not alias_exp.endswith(' '):
1068	# alias e='echo [ ' is the same expansion as
1069	# alias e='echo ['
1070	# The trailing space indicates whether we should continue to expand
1071	# aliases; it's not part of it.
1072	expanded.append(' ')
1073	break # No more expansions
1074
1075	if len(expanded) == 0: # No expansions; caller does parsing.
1076	return None
1077
1078	# We are expanding an alias, so copy the rest of the words and re-parse.
1079	if i < n:
1080	left_tok = location.LeftTokenForWord(words[i])
1081	right_tok = location.RightTokenForWord(words[-1])
1082
1083	# OLD CONSTRAINT
1084	#assert left_tok.line_id == right_tok.line_id
1085
1086	words_str = self.arena.SnipCodeString(left_tok, right_tok)
1087	expanded.append(words_str)
1088
1089	code_str = ''.join(expanded)
1090
1091	# TODO:
1092	# Aliases break static parsing (like backticks), so use our own Arena.
1093	# This matters for Hay, which calls SaveLinesAndDiscard().
1094	# arena = alloc.Arena()
1095	arena = self.arena
1096
1097	line_reader = reader.StringLineReader(code_str, arena)
1098	cp = self.parse_ctx.MakeOshParser(line_reader)
1099	cp.Init_AliasesInFlight(aliases_in_flight)
1100
1101	# break circular dep
1102	from frontend import parse_lib
1103
1104	# The interaction between COMPLETION and ALIASES requires special care.
1105	# See docstring of BeginAliasExpansion() in parse_lib.py.
1106	src = source.Alias(first_word_str, argv0_loc)
1107	with alloc.ctx_SourceCode(arena, src):
1108	with parse_lib.ctx_Alias(self.parse_ctx.trail):
1109	try:
1110	# _ParseCommandTerm() handles multiline commands, compound
1111	# commands, etc. as opposed to ParseLogicalLine()
1112	node = cp._ParseCommandTerm()
1113	except error.Parse as e:
1114	# Failure to parse alias expansion is a fatal error
1115	# We don't need more handling here/
1116	raise
1117
1118	if 0:
1119	log('AFTER expansion:')
1120	node.PrettyPrint()
1121
1122	return node
1123
1124	def ParseSimpleCommand(self):
1125	# type: () -> command_t
1126	"""Fixed transcription of the POSIX grammar
1127
1128	io_file : '<' filename
1129	\| LESSAND filename
1130	...
1131
1132	io_here : DLESS here_end
1133	\| DLESSDASH here_end
1134
1135	redirect : IO_NUMBER (io_redirect \| io_here)
1136
1137	prefix_part : ASSIGNMENT_WORD \| redirect
1138	cmd_part : WORD \| redirect
1139
1140	assign_kw : Declare \| Export \| Local \| Readonly
1141
1142	# Without any words it is parsed as a command, not an assignment
1143	assign_listing : assign_kw
1144
1145	# Now we have something to do (might be changing assignment flags too)
1146	# NOTE: any prefixes should be a warning, but they are allowed in shell.
1147	assignment : prefix_part* assign_kw (WORD \| ASSIGNMENT_WORD)+
1148
1149	# an external command, a function call, or a builtin -- a "word_command"
1150	word_command : prefix_part* cmd_part+
1151
1152	simple_command : assign_listing
1153	\| assignment
1154	\| proc_command
1155
1156	Simple imperative algorithm:
1157
1158	1) Read a list of words and redirects. Append them to separate lists.
1159	2) Look for the first non-assignment word. If it's declare, etc., then
1160	keep parsing words AND assign words. Otherwise, just parse words.
1161	3) If there are no non-assignment words, then it's a global assignment.
1162
1163	{ redirects, global assignments } OR
1164	{ redirects, prefix_bindings, words } OR
1165	{ redirects, ERROR_prefix_bindings, keyword, assignments, words }
1166
1167	THEN CHECK that prefix bindings don't have any array literal parts!
1168	global assignment and keyword assignments can have the of course.
1169	well actually EXPORT shouldn't have them either -- WARNING
1170
1171	3 cases we want to warn: prefix_bindings for assignment, and array literal
1172	in prefix bindings, or export
1173
1174	A command can be an assignment word, word, or redirect on its own.
1175
1176	ls
1177	>out.txt
1178
1179	>out.txt FOO=bar # this touches the file
1180
1181	Or any sequence:
1182	ls foo bar
1183	<in.txt ls foo bar >out.txt
1184	<in.txt ls >out.txt foo bar
1185
1186	Or add one or more environment bindings:
1187	VAR=val env
1188	>out.txt VAR=val env
1189
1190	here_end vs filename is a matter of whether we test that it's quoted. e.g.
1191	<<EOF vs <<'EOF'.
1192	"""
1193	redirects, words, typed_args, block = self._ScanSimpleCommand()
1194
1195	typed_loc = None # type: Optional[Token]
1196	if block:
1197	typed_loc = block.brace_group.left
1198	if typed_args:
1199	typed_loc = typed_args.left # preferred over block location
1200
1201	if len(words) == 0: # e.g. >out.txt # redirect without words
1202	assert len(redirects) != 0
1203	if typed_loc is not None:
1204	p_die("Unexpected typed args", typed_loc)
1205	return command.Redirect(command.NoOp, redirects)
1206
1207	preparsed_list, suffix_words = _SplitSimpleCommandPrefix(words)
1208	if len(preparsed_list):
1209	# Disallow X=Y inside proc and func
1210	# and inside Hay Attr blocks
1211	# But allow X=Y at the top level
1212	# for interactive use foo=bar
1213	# for global constants GLOBAL=~/src
1214	# because YSH assignment doesn't have tilde sub
1215	if len(suffix_words) == 0:
1216	if (self.cmd_mode != cmd_mode_e.Shell or
1217	(len(self.hay_attrs_stack) and self.hay_attrs_stack[-1])):
1218	p_die('Use var/setvar to assign in YSH',
1219	preparsed_list[0].left)
1220
1221	# Set a reference to words and redirects for completion. We want to
1222	# inspect this state after a failed parse.
1223	self.parse_ctx.trail.SetLatestWords(suffix_words, redirects)
1224
1225	if len(suffix_words) == 0:
1226	if typed_loc is not None:
1227	p_die("Unexpected typed args", typed_loc)
1228
1229	# ShAssignment: No suffix words like ONE=1 a[x]=1 TWO=2
1230	pairs = [] # type: List[AssignPair]
1231	for preparsed in preparsed_list:
1232	pairs.append(
1233	_MakeAssignPair(self.parse_ctx, preparsed, self.arena))
1234
1235	left_tok = location.LeftTokenForCompoundWord(words[0])
1236	assign_node = command.ShAssignment(left_tok, pairs)
1237	if len(redirects):
1238	return command.Redirect(assign_node, redirects)
1239	else:
1240	return assign_node
1241
1242	kind, kw_token = word_.IsControlFlow(suffix_words[0])
1243
1244	if kind == Kind.ControlFlow:
1245	if not self.parse_opts.parse_ignored() and len(redirects):
1246	p_die("Control flow shouldn't have redirects", kw_token)
1247	if len(preparsed_list): # FOO=bar local spam=eggs not allowed
1248	p_die("Control flow shouldn't have environment bindings",
1249	preparsed_list[0].left)
1250
1251	if kw_token.id == Id.ControlFlow_Return:
1252	# return x - inside procs and shell functions
1253	# return (x) - inside funcs
1254	if typed_args is None:
1255	if self.cmd_mode not in (cmd_mode_e.Shell,
1256	cmd_mode_e.Proc):
1257	p_die('Shell-style returns not allowed here', kw_token)
1258	else:
1259	if self.cmd_mode != cmd_mode_e.Func:
1260	p_die('Typed return is only allowed inside func',
1261	typed_loc)
1262	if len(typed_args.pos_args) != 1:
1263	p_die("Typed return expects one argument", typed_loc)
1264	if len(typed_args.named_args) != 0:
1265	p_die("Typed return doesn't take named arguments",
1266	typed_loc)
1267	return command.Retval(kw_token, typed_args.pos_args[0])
1268
1269	# Except for return (x), we shouldn't have typed args
1270	if typed_loc is not None:
1271	p_die("Unexpected typed args", typed_loc)
1272
1273	# Attach the token for errors. (ShAssignment may not need it.)
1274	if len(suffix_words) == 1:
1275	arg_word = None # type: Optional[word_t]
1276	elif len(suffix_words) == 2:
1277	arg_word = suffix_words[1]
1278	else:
1279	p_die('Unexpected argument to %r' % lexer.TokenVal(kw_token),
1280	loc.Word(suffix_words[2]))
1281
1282	return command.ControlFlow(kw_token, arg_word)
1283
1284	# Alias expansion only understands words, not typed args ( ) or block { }
1285	if not typed_args and not block and self.parse_opts.expand_aliases():
1286	# If any expansions were detected, then parse again.
1287	expanded_node = self._MaybeExpandAliases(suffix_words)
1288	if expanded_node:
1289	# Attach env bindings and redirects to the expanded node.
1290	more_env = [] # type: List[EnvPair]
1291	_AppendMoreEnv(preparsed_list, more_env)
1292	exp = command.ExpandedAlias(expanded_node, more_env)
1293	if len(redirects):
1294	return command.Redirect(exp, redirects)
1295	else:
1296	return exp
1297
1298	# TODO: check that we don't have env1=x x[1]=y env2=z here.
1299
1300	# FOO=bar printenv.py FOO
1301	node = _MakeSimpleCommand(preparsed_list, suffix_words, typed_args,
1302	block)
1303	if len(redirects):
1304	return command.Redirect(node, redirects)
1305	else:
1306	return node
1307
1308	def ParseBraceGroup(self):
1309	# type: () -> BraceGroup
1310	"""
1311	Original:
1312	brace_group : LBrace command_list RBrace ;
1313
1314	YSH:
1315	brace_group : LBrace (Op_Newline IgnoredComment?)? command_list RBrace ;
1316
1317	The doc comment can only occur if there's a newline.
1318	"""
1319	ate = self._Eat(Id.Lit_LBrace)
1320	left = word_.BraceToken(ate)
1321
1322	doc_word = None # type: word_t
1323	self._GetWord()
1324	if self.c_id == Id.Op_Newline:
1325	self._SetNext()
1326	# Set a flag so we don't skip over ###
1327	with word_.ctx_EmitDocToken(self.w_parser):
1328	self._GetWord()
1329
1330	if self.c_id == Id.Ignored_Comment:
1331	doc_word = self.cur_word
1332	self._SetNext()
1333
1334	# Id.Ignored_Comment means it's a Token, or None
1335	doc_token = cast(Token, doc_word)
1336
1337	c_list = self._ParseCommandList()
1338
1339	ate = self._Eat(Id.Lit_RBrace)
1340	right = word_.BraceToken(ate)
1341
1342	# Note(andychu): Related ASDL bug #1216. Choosing the Python [] behavior
1343	# would allow us to revert this back to None, which was changed in
1344	# https://github.com/oilshell/oil/pull/1211. Choosing the C++ nullptr
1345	# behavior saves allocations, but is less type safe.
1346	return BraceGroup(left, doc_token, c_list.children, right)
1347
1348	def ParseDoGroup(self):
1349	# type: () -> command.DoGroup
1350	"""Used by ForEach, ForExpr, While, Until. Should this be a Do node?
1351
1352	do_group : Do command_list Done ; /* Apply rule 6 */
1353	"""
1354	ate = self._Eat(Id.KW_Do)
1355	do_kw = word_.AsKeywordToken(ate)
1356
1357	c_list = self._ParseCommandList() # could be anything
1358
1359	ate = self._Eat(Id.KW_Done)
1360	done_kw = word_.AsKeywordToken(ate)
1361
1362	return command.DoGroup(do_kw, c_list.children, done_kw)
1363
1364	def ParseForWords(self):
1365	# type: () -> Tuple[List[CompoundWord], Optional[Token]]
1366	"""
1367	for_words : WORD* for_sep
1368	;
1369	for_sep : ';' newline_ok
1370	\| NEWLINES
1371	;
1372	"""
1373	words = [] # type: List[CompoundWord]
1374	# The token of any semi-colon, so we can remove it.
1375	semi_tok = None # type: Optional[Token]
1376
1377	while True:
1378	self._GetWord()
1379	if self.c_id == Id.Op_Semi:
1380	tok = cast(Token, self.cur_word)
1381	semi_tok = tok
1382	self._SetNext()
1383	self._NewlineOk()
1384	break
1385	elif self.c_id == Id.Op_Newline:
1386	self._SetNext()
1387	break
1388	elif self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace:
1389	break
1390
1391	if self.cur_word.tag() != word_e.Compound:
1392	# TODO: Can we also show a pointer to the 'for' keyword?
1393	p_die('Invalid word in for loop', loc.Word(self.cur_word))
1394
1395	w2 = cast(CompoundWord, self.cur_word)
1396	words.append(w2)
1397	self._SetNext()
1398	return words, semi_tok
1399
1400	def _ParseForExprLoop(self, for_kw):
1401	# type: (Token) -> command.ForExpr
1402	"""
1403	Shell:
1404	for '((' init ';' cond ';' update '))' for_sep? do_group
1405
1406	YSH:
1407	for '((' init ';' cond ';' update '))' for_sep? brace_group
1408	"""
1409	node = self.w_parser.ReadForExpression()
1410	node.keyword = for_kw
1411
1412	self._SetNext()
1413
1414	self._GetWord()
1415	if self.c_id == Id.Op_Semi:
1416	self._SetNext()
1417	self._NewlineOk()
1418	elif self.c_id == Id.Op_Newline:
1419	self._SetNext()
1420	elif self.c_id == Id.KW_Do: # missing semicolon/newline allowed
1421	pass
1422	elif self.c_id == Id.Lit_LBrace: # does NOT require parse_brace
1423	pass
1424	else:
1425	p_die('Invalid word after for expression', loc.Word(self.cur_word))
1426
1427	if self.c_id == Id.Lit_LBrace:
1428	node.body = self.ParseBraceGroup()
1429	else:
1430	node.body = self.ParseDoGroup()
1431	return node
1432
1433	def _ParseForEachLoop(self, for_kw):
1434	# type: (Token) -> command.ForEach
1435	node = command.ForEach.CreateNull(alloc_lists=True)
1436	node.keyword = for_kw
1437
1438	num_iter_names = 0
1439	while True:
1440	w = self.cur_word
1441
1442	# Hack that makes the language more familiar:
1443	# - 'x, y' is accepted, but not 'x,y' or 'x ,y'
1444	# - 'x y' is also accepted but not idiomatic.
1445	UP_w = w
1446	if w.tag() == word_e.Compound:
1447	w = cast(CompoundWord, UP_w)
1448	if word_.LiteralId(w.parts[-1]) == Id.Lit_Comma:
1449	w.parts.pop()
1450
1451	ok, iter_name, quoted = word_.StaticEval(w)
1452	if not ok or quoted: # error: for $x
1453	p_die('Expected loop variable (a constant word)', loc.Word(w))
1454
1455	if not match.IsValidVarName(iter_name): # error: for -
1456	# TODO: consider commas?
1457	if ',' in iter_name:
1458	p_die('Loop variables look like x, y (fix spaces)',
1459	loc.Word(w))
1460	p_die('Invalid loop variable name %r' % iter_name, loc.Word(w))
1461
1462	node.iter_names.append(iter_name)
1463	num_iter_names += 1
1464	self._SetNext()
1465
1466	self._GetWord()
1467	# 'in' or 'do' or ';' or Op_Newline marks the end of variable names
1468	# Subtlety: 'var' is KW_Var and is a valid loop name
1469	if self.c_id in (Id.KW_In, Id.KW_Do) or self.c_kind == Kind.Op:
1470	break
1471
1472	if num_iter_names == 3:
1473	p_die('Unexpected word after 3 loop variables',
1474	loc.Word(self.cur_word))
1475
1476	self._NewlineOk()
1477
1478	self._GetWord()
1479	if self.c_id == Id.KW_In:
1480	expr_blame = word_.AsKeywordToken(self.cur_word)
1481
1482	self._SetNext() # skip in
1483
1484	next_id = self.w_parser.LookPastSpace()
1485	#log('%s', Id_str(next_id))
1486
1487	if next_id == Id.Op_LParen: # for x in (expr) {
1488	enode = self.w_parser.ParseYshExprForCommand()
1489	node.iterable = for_iter.YshExpr(enode, expr_blame)
1490
1491	# We don't accept for x in (obj); do ...
1492	self._GetWord()
1493	if self.c_id != Id.Lit_LBrace:
1494	p_die('Expected { after iterable expression',
1495	loc.Word(self.cur_word))
1496
1497	elif next_id == Id.Redir_LessGreat: # for x in <> {
1498	# <> is Id.Redir_Great - reuse this for simplicity
1499
1500	w = self._Eat(Id.Redir_LessGreat)
1501	left = word_.AsOperatorToken(w)
1502
1503	node.iterable = for_iter.Files(left, [])
1504
1505	# Must be { not 'do'
1506	self._GetWord()
1507	if self.c_id != Id.Lit_LBrace:
1508	p_die('Expected { after files', loc.Word(self.cur_word))
1509
1510	elif next_id == Id.Redir_Less: # for x in < > {
1511	w = self._Eat(Id.Redir_Less)
1512	left = word_.AsOperatorToken(w)
1513
1514	# TODO: we could accept
1515	#
1516	# for x in < README.md *.py > {
1517	# for x in < @myfiles > {
1518	#
1519	# And set _filename _line_num, similar to awk
1520
1521	self._Eat(Id.Redir_Great)
1522
1523	node.iterable = for_iter.Files(left, [])
1524
1525	# Must be { not 'do'
1526	self._GetWord()
1527	if self.c_id != Id.Lit_LBrace:
1528	p_die('Expected { after files', loc.Word(self.cur_word))
1529
1530	else:
1531	semi_tok = None # type: Optional[Token]
1532	iter_words, semi_tok = self.ParseForWords()
1533	node.semi_tok = semi_tok
1534
1535	if not self.parse_opts.parse_bare_word() and len(
1536	iter_words) == 1:
1537	ok, s, quoted = word_.StaticEval(iter_words[0])
1538	if ok and match.IsValidVarName(s) and not quoted:
1539	p_die(
1540	'Surround this word with either parens or quotes (parse_bare_word)',
1541	loc.Word(iter_words[0]))
1542
1543	words2 = braces.BraceDetectAll(iter_words)
1544	words3 = word_.TildeDetectAll(words2)
1545	node.iterable = for_iter.Words(words3)
1546
1547	# Now that we know there are words, do an extra check
1548	if num_iter_names > 2:
1549	p_die('Expected at most 2 loop variables', for_kw)
1550
1551	elif self.c_id == Id.KW_Do:
1552	node.iterable = for_iter.Args # implicitly loop over "$@"
1553	# do not advance
1554
1555	elif self.c_id == Id.Op_Semi: # for x; do
1556	node.iterable = for_iter.Args # implicitly loop over "$@"
1557	self._SetNext()
1558
1559	else: # for foo BAD
1560	p_die('Unexpected word after for loop variable',
1561	loc.Word(self.cur_word))
1562
1563	self._GetWord()
1564	if self.c_id == Id.Lit_LBrace: # parse_opts.parse_brace() must be on
1565	node.body = self.ParseBraceGroup()
1566	else:
1567	node.body = self.ParseDoGroup()
1568
1569	return node
1570
1571	def ParseFor(self):
1572	# type: () -> command_t
1573	"""
1574	TODO: Update the grammar
1575
1576	for_clause : For for_name newline_ok (in for_words? for_sep)? do_group ;
1577	\| For '((' ... TODO
1578	"""
1579	ate = self._Eat(Id.KW_For)
1580	for_kw = word_.AsKeywordToken(ate)
1581
1582	self._GetWord()
1583	if self.c_id == Id.Op_DLeftParen:
1584	if not self.parse_opts.parse_dparen():
1585	p_die("Bash for loops aren't allowed (parse_dparen)",
1586	loc.Word(self.cur_word))
1587
1588	# for (( i = 0; i < 10; i++)
1589	n1 = self._ParseForExprLoop(for_kw)
1590	return self._MaybeParseRedirectList(n1)
1591	else:
1592	# for x in a b; do echo hi; done
1593	n2 = self._ParseForEachLoop(for_kw)
1594	return self._MaybeParseRedirectList(n2)
1595
1596	def _ParseConditionList(self):
1597	# type: () -> condition_t
1598	"""
1599	condition_list: command_list
1600
1601	This is a helper to parse a condition list for if commands and while/until
1602	loops. It will throw a parse error if there are no conditions in the list.
1603	"""
1604	self.allow_block = False
1605	commands = self._ParseCommandList()
1606	self.allow_block = True
1607
1608	if len(commands.children) == 0:
1609	p_die("Expected a condition", loc.Word(self.cur_word))
1610
1611	return condition.Shell(commands.children)
1612
1613	def ParseWhileUntil(self, keyword):
1614	# type: (Token) -> command.WhileUntil
1615	"""
1616	while_clause : While command_list do_group ;
1617	until_clause : Until command_list do_group ;
1618	"""
1619	self._SetNext() # skip keyword
1620
1621	if (self.parse_opts.parse_paren() and
1622	self.w_parser.LookPastSpace() == Id.Op_LParen):
1623	enode = self.w_parser.ParseYshExprForCommand()
1624	cond = condition.YshExpr(enode) # type: condition_t
1625	else:
1626	cond = self._ParseConditionList()
1627
1628	# NOTE: The LSTs will be different for OSH and YSH, but the execution
1629	# should be unchanged. To be sure we should desugar.
1630	self._GetWord()
1631	if self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace:
1632	# while test -f foo {
1633	body_node = self.ParseBraceGroup() # type: command_t
1634	else:
1635	body_node = self.ParseDoGroup()
1636
1637	return command.WhileUntil(keyword, cond, body_node)
1638
1639	def ParseCaseArm(self):
1640	# type: () -> CaseArm
1641	"""
1642	case_item: '('? pattern ('\|' pattern)* ')'
1643	newline_ok command_term? trailer? ;
1644
1645	Looking at '(' or pattern
1646	"""
1647	self.lexer.PushHint(Id.Op_RParen, Id.Right_CasePat)
1648
1649	left_tok = location.LeftTokenForWord(self.cur_word) # ( or pat
1650
1651	if self.c_id == Id.Op_LParen: # Optional (
1652	self._SetNext()
1653
1654	pat_words = [] # type: List[word_t]
1655	while True:
1656	self._GetWord()
1657	if self.c_kind != Kind.Word:
1658	p_die('Expected case pattern', loc.Word(self.cur_word))
1659	pat_words.append(self.cur_word)
1660	self._SetNext()
1661
1662	self._GetWord()
1663	if self.c_id == Id.Op_Pipe:
1664	self._SetNext()
1665	else:
1666	break
1667
1668	ate = self._Eat(Id.Right_CasePat)
1669	middle_tok = word_.AsOperatorToken(ate)
1670
1671	self._NewlineOk()
1672
1673	self._GetWord()
1674	if self.c_id not in (Id.Op_DSemi, Id.Op_SemiAmp, Id.Op_DSemiAmp,
1675	Id.KW_Esac):
1676	c_list = self._ParseCommandTerm()
1677	action_children = c_list.children
1678	else:
1679	action_children = []
1680
1681	dsemi_tok = None # type: Token
1682	self._GetWord()
1683	if self.c_id == Id.KW_Esac: # missing last ;;
1684	pass
1685	elif self.c_id in (Id.Op_DSemi, Id.Op_SemiAmp, Id.Op_DSemiAmp):
1686	dsemi_tok = word_.AsOperatorToken(self.cur_word)
1687	self._SetNext()
1688	else:
1689	# Happens on EOF
1690	p_die('Expected ;; or esac', loc.Word(self.cur_word))
1691
1692	self._NewlineOk()
1693
1694	return CaseArm(left_tok, pat.Words(pat_words), middle_tok,
1695	action_children, dsemi_tok)
1696
1697	def ParseYshCaseArm(self, discriminant):
1698	# type: (Id_t) -> CaseArm
1699	"""
1700	case_item : pattern newline_ok brace_group newline_ok
1701	pattern : pat_words
1702	\| pat_exprs
1703	\| pat_eggex
1704	\| pat_else
1705	pat_words : pat_word (newline_ok '\|' newline_ok pat_word)*
1706	pat_exprs : pat_expr (newline_ok '\|' newline_ok pat_expr)*
1707	pat_word : WORD
1708	pat_eggex : '/' oil_eggex '/'
1709	pat_expr : '(' oil_expr ')'
1710	pat_else : '(' Id.KW_Else ')'
1711
1712	Looking at: 'pattern'
1713
1714	Note that the trailing `newline_ok` in `case_item` is handled by
1715	`ParseYshCase`. We do this because parsing that `newline_ok` returns
1716	the next "discriminant" for the next token, so it makes more sense to
1717	handle it there.
1718	"""
1719	left_tok = None # type: Token
1720	pattern = None # type: pat_t
1721
1722	if discriminant in (Id.Op_LParen, Id.Arith_Slash):
1723	# pat_exprs, pat_else or pat_eggex
1724	pattern, left_tok = self.w_parser.ParseYshCasePattern()
1725	else:
1726	# pat_words
1727	pat_words = [] # type: List[word_t]
1728	while True:
1729	self._GetWord()
1730	if self.c_kind != Kind.Word:
1731	p_die('Expected case pattern', loc.Word(self.cur_word))
1732	pat_words.append(self.cur_word)
1733	self._SetNext()
1734
1735	if not left_tok:
1736	left_tok = location.LeftTokenForWord(self.cur_word)
1737
1738	self._NewlineOk()
1739
1740	self._GetWord()
1741	if self.c_id == Id.Op_Pipe:
1742	self._SetNext()
1743	self._NewlineOk()
1744	else:
1745	break
1746	pattern = pat.Words(pat_words)
1747
1748	self._NewlineOk()
1749	action = self.ParseBraceGroup()
1750
1751	# The left token of the action is our "middle" token
1752	return CaseArm(left_tok, pattern, action.left, action.children,
1753	action.right)
1754
1755	def ParseYshCase(self, case_kw):
1756	# type: (Token) -> command.Case
1757	"""
1758	ysh_case : Case '(' expr ')' LBrace newline_ok ysh_case_arm* RBrace ;
1759
1760	Looking at: token after 'case'
1761	"""
1762	enode = self.w_parser.ParseYshExprForCommand()
1763	to_match = case_arg.YshExpr(enode)
1764
1765	ate = self._Eat(Id.Lit_LBrace)
1766	arms_start = word_.BraceToken(ate)
1767
1768	discriminant = self.w_parser.NewlineOkForYshCase()
1769
1770	# Note: for now, zero arms are accepted, just like POSIX case $x in esac
1771	arms = [] # type: List[CaseArm]
1772	while discriminant != Id.Op_RBrace:
1773	arm = self.ParseYshCaseArm(discriminant)
1774	arms.append(arm)
1775
1776	discriminant = self.w_parser.NewlineOkForYshCase()
1777
1778	# NewlineOkForYshCase leaves the lexer in lex_mode_e.Expr. So the '}'
1779	# token is read as an Id.Op_RBrace, but we need to store this as a
1780	# Id.Lit_RBrace.
1781	ate = self._Eat(Id.Op_RBrace)
1782	arms_end = word_.AsOperatorToken(ate)
1783	arms_end.id = Id.Lit_RBrace
1784
1785	return command.Case(case_kw, to_match, arms_start, arms, arms_end)
1786
1787	def ParseOldCase(self, case_kw):
1788	# type: (Token) -> command.Case
1789	"""
1790	case_clause : Case WORD newline_ok In newline_ok case_arm* Esac ;
1791
1792	-> Looking at WORD
1793
1794	FYI original POSIX case list, which takes pains for DSEMI
1795
1796	case_list: case_item (DSEMI newline_ok case_item)* DSEMI? newline_ok;
1797	"""
1798	self._GetWord()
1799	w = self.cur_word
1800	if not self.parse_opts.parse_bare_word():
1801	ok, s, quoted = word_.StaticEval(w)
1802	if ok and not quoted:
1803	p_die(
1804	"This is a constant string. You may want a variable like $x (parse_bare_word)",
1805	loc.Word(w))
1806
1807	if w.tag() != word_e.Compound:
1808	p_die("Expected a word to match against", loc.Word(w))
1809
1810	to_match = case_arg.Word(w)
1811	self._SetNext() # past WORD
1812
1813	self._NewlineOk()
1814
1815	ate = self._Eat(Id.KW_In)
1816	arms_start = word_.AsKeywordToken(ate)
1817
1818	self._NewlineOk()
1819
1820	arms = [] # type: List[CaseArm]
1821	while True:
1822	self._GetWord()
1823	if self.c_id == Id.KW_Esac:
1824	break
1825	# case arm should begin with a pattern word or (
1826	if self.c_kind != Kind.Word and self.c_id != Id.Op_LParen:
1827	break
1828
1829	arm = self.ParseCaseArm()
1830	arms.append(arm)
1831
1832	ate = self._Eat(Id.KW_Esac)
1833	arms_end = word_.AsKeywordToken(ate)
1834
1835	# no redirects yet
1836	return command.Case(case_kw, to_match, arms_start, arms, arms_end)
1837
1838	def ParseCase(self):
1839	# type: () -> command.Case
1840	"""
1841	case_clause : old_case # from POSIX
1842	\| ysh_case
1843	;
1844
1845	Looking at 'Case'
1846	"""
1847	case_kw = word_.AsKeywordToken(self.cur_word)
1848	self._SetNext() # past 'case'
1849
1850	if self.w_parser.LookPastSpace() == Id.Op_LParen:
1851	return self.ParseYshCase(case_kw)
1852	else:
1853	return self.ParseOldCase(case_kw)
1854
1855	def _ParseYshElifElse(self, if_node):
1856	# type: (command.If) -> None
1857	"""If test -f foo { echo foo.
1858
1859	} elif test -f bar; test -f spam { ^ we parsed up to here echo
1860	bar } else { echo none }
1861	"""
1862	arms = if_node.arms
1863
1864	while self.c_id == Id.KW_Elif:
1865	elif_kw = word_.AsKeywordToken(self.cur_word)
1866	self._SetNext() # skip elif
1867	if (self.parse_opts.parse_paren() and
1868	self.w_parser.LookPastSpace() == Id.Op_LParen):
1869	enode = self.w_parser.ParseYshExprForCommand()
1870	cond = condition.YshExpr(enode) # type: condition_t
1871	else:
1872	self.allow_block = False
1873	commands = self._ParseCommandList()
1874	self.allow_block = True
1875	cond = condition.Shell(commands.children)
1876
1877	body = self.ParseBraceGroup()
1878	self._GetWord()
1879
1880	arm = IfArm(elif_kw, cond, None, body.children, None)
1881	arms.append(arm)
1882
1883	self._GetWord()
1884	if self.c_id == Id.KW_Else:
1885	self._SetNext()
1886	body = self.ParseBraceGroup()
1887	if_node.else_action = body.children
1888
1889	def _ParseYshIf(self, if_kw, cond):
1890	# type: (Token, condition_t) -> command.If
1891	"""
1892	if test -f foo {
1893	# ^ we parsed up to here
1894	echo foo
1895	} elif test -f bar; test -f spam {
1896	echo bar
1897	} else {
1898	echo none
1899	}
1900	NOTE: If you do something like if test -n foo{, the parser keeps going, and
1901	the error is confusing because it doesn't point to the right place.
1902
1903	I think we might need strict_brace so that foo{ is disallowed. It has to
1904	be foo\{ or foo{a,b}. Or just turn that on with parse_brace? After you
1905	form ANY CompoundWord, make sure it's balanced for Lit_LBrace and
1906	Lit_RBrace? Maybe this is pre-parsing step in the WordParser?
1907	"""
1908	if_node = command.If.CreateNull(alloc_lists=True)
1909	if_node.if_kw = if_kw
1910
1911	body1 = self.ParseBraceGroup()
1912	# Every arm has 1 spid, unlike shell-style
1913	# TODO: We could get the spids from the brace group.
1914	arm = IfArm(if_kw, cond, None, body1.children, None)
1915
1916	if_node.arms.append(arm)
1917
1918	self._GetWord()
1919	if self.c_id in (Id.KW_Elif, Id.KW_Else):
1920	self._ParseYshElifElse(if_node)
1921	# the whole if node has the 'else' spid, unlike shell-style there's no 'fi'
1922	# spid because that's in the BraceGroup.
1923	return if_node
1924
1925	def _ParseElifElse(self, if_node):
1926	# type: (command.If) -> None
1927	"""
1928	else_part: (Elif command_list Then command_list)* Else command_list ;
1929	"""
1930	arms = if_node.arms
1931
1932	self._GetWord()
1933	while self.c_id == Id.KW_Elif:
1934	elif_kw = word_.AsKeywordToken(self.cur_word)
1935	self._SetNext() # past 'elif'
1936
1937	cond = self._ParseConditionList()
1938
1939	ate = self._Eat(Id.KW_Then)
1940	then_kw = word_.AsKeywordToken(ate)
1941
1942	body = self._ParseCommandList()
1943	arm = IfArm(elif_kw, cond, then_kw, body.children, then_kw)
1944
1945	arms.append(arm)
1946
1947	self._GetWord()
1948	if self.c_id == Id.KW_Else:
1949	else_kw = word_.AsKeywordToken(self.cur_word)
1950	self._SetNext() # past 'else'
1951	body = self._ParseCommandList()
1952	if_node.else_action = body.children
1953	else:
1954	else_kw = None
1955
1956	if_node.else_kw = else_kw
1957
1958	def ParseIf(self):
1959	# type: () -> command.If
1960	"""
1961	if_clause : If command_list Then command_list else_part? Fi ;
1962
1963	open : '{' \| Then
1964	close : '}' \| Fi
1965
1966	ysh_if : If ( command_list \| '(' expr ')' )
1967	open command_list else_part? close;
1968
1969	There are 2 conditionals here: parse_paren, then parse_brace
1970	"""
1971	if_node = command.If.CreateNull(alloc_lists=True)
1972	if_kw = word_.AsKeywordToken(self.cur_word)
1973	if_node.if_kw = if_kw
1974	self._SetNext() # past 'if'
1975
1976	if (self.parse_opts.parse_paren() and
1977	self.w_parser.LookPastSpace() == Id.Op_LParen):
1978	# if (x + 1)
1979	enode = self.w_parser.ParseYshExprForCommand()
1980	cond = condition.YshExpr(enode) # type: condition_t
1981	else:
1982	# if echo 1; echo 2; then
1983	# Remove ambiguity with if cd / {
1984	cond = self._ParseConditionList()
1985
1986	self._GetWord()
1987	if self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace:
1988	return self._ParseYshIf(if_kw, cond)
1989
1990	ate = self._Eat(Id.KW_Then)
1991	then_kw = word_.AsKeywordToken(ate)
1992
1993	body = self._ParseCommandList()
1994
1995	# First arm
1996	arm = IfArm(if_kw, cond, then_kw, body.children, then_kw)
1997	if_node.arms.append(arm)
1998
1999	# 2nd to Nth arm
2000	if self.c_id in (Id.KW_Elif, Id.KW_Else):
2001	self._ParseElifElse(if_node)
2002
2003	ate = self._Eat(Id.KW_Fi)
2004	if_node.fi_kw = word_.AsKeywordToken(ate)
2005
2006	return if_node
2007
2008	def ParseTime(self):
2009	# type: () -> command_t
2010	"""Time [-p] pipeline.
2011
2012	According to bash help.
2013	"""
2014	time_kw = word_.AsKeywordToken(self.cur_word)
2015	self._SetNext() # skip time
2016	pipeline = self.ParsePipeline()
2017	return command.TimeBlock(time_kw, pipeline)
2018
2019	def ParseCompoundCommand(self):
2020	# type: () -> command_t
2021	"""
2022	Refactoring: we put io_redirect* here instead of in function_body and
2023	command.
2024
2025	compound_command : brace_group io_redirect*
2026	\| subshell io_redirect*
2027	\| for_clause io_redirect*
2028	\| while_clause io_redirect*
2029	\| until_clause io_redirect*
2030	\| if_clause io_redirect*
2031	\| case_clause io_redirect*
2032
2033	# bash extensions
2034	\| time_clause
2035	\| [[ BoolExpr ]]
2036	\| (( ArithExpr ))
2037	"""
2038	self._GetWord()
2039	if self.c_id == Id.Lit_LBrace:
2040	n1 = self.ParseBraceGroup()
2041	return self._MaybeParseRedirectList(n1)
2042	if self.c_id == Id.Op_LParen:
2043	n2 = self.ParseSubshell()
2044	return self._MaybeParseRedirectList(n2)
2045
2046	if self.c_id == Id.KW_For:
2047	# Note: Redirects parsed in this call. POSIX for and bash for ((
2048	# have different nodetypes.
2049	return self.ParseFor()
2050	if self.c_id in (Id.KW_While, Id.KW_Until):
2051	keyword = word_.AsKeywordToken(self.cur_word)
2052	n3 = self.ParseWhileUntil(keyword)
2053	return self._MaybeParseRedirectList(n3)
2054
2055	if self.c_id == Id.KW_If:
2056	n4 = self.ParseIf()
2057	return self._MaybeParseRedirectList(n4)
2058
2059	if self.c_id == Id.KW_Case:
2060	n5 = self.ParseCase()
2061	return self._MaybeParseRedirectList(n5)
2062
2063	if self.c_id == Id.KW_DLeftBracket:
2064	if not self.parse_opts.parse_dbracket():
2065	p_die('Bash [[ not allowed in YSH (parse_dbracket)',
2066	loc.Word(self.cur_word))
2067	n6 = self.ParseDBracket()
2068	return self._MaybeParseRedirectList(n6)
2069	if self.c_id == Id.Op_DLeftParen:
2070	if not self.parse_opts.parse_dparen():
2071	p_die(
2072	'Bash (( not allowed in YSH (parse_dparen, see OILS-ERR-14 for wart)',
2073	loc.Word(self.cur_word))
2074	n7 = self.ParseDParen()
2075	return self._MaybeParseRedirectList(n7)
2076
2077	# bash extensions: no redirects
2078	if self.c_id == Id.KW_Time:
2079	return self.ParseTime()
2080
2081	# Happens in function body, e.g. myfunc() oops
2082	p_die(
2083	'Unexpected word while parsing compound command (%s)' %
2084	Id_str(self.c_id), loc.Word(self.cur_word))
2085	assert False # for MyPy
2086
2087	def ParseFunctionDef(self):
2088	# type: () -> command.ShFunction
2089	"""
2090	function_header : fname '(' ')'
2091	function_def : function_header newline_ok function_body ;
2092
2093	Precondition: Looking at the function name.
2094
2095	NOTE: There is an ambiguity with:
2096
2097	function foo ( echo hi ) and
2098	function foo () ( echo hi )
2099
2100	Bash only accepts the latter, though it doesn't really follow a grammar.
2101	"""
2102	word0 = cast(CompoundWord, self.cur_word) # caller ensures validity
2103	name = word_.ShFunctionName(word0)
2104	if len(name) == 0: # example: foo$x is invalid
2105	p_die('Invalid function name', loc.Word(word0))
2106
2107	part0 = word0.parts[0]
2108	# If we got a non-empty string from ShFunctionName, this should be true.
2109	assert part0.tag() == word_part_e.Literal
2110	blame_tok = cast(Token, part0) # for ctx_VarChecker
2111
2112	self._SetNext() # move past function name
2113
2114	# Must be true because of lookahead
2115	self._GetWord()
2116	assert self.c_id == Id.Op_LParen, self.cur_word
2117
2118	self.lexer.PushHint(Id.Op_RParen, Id.Right_ShFunction)
2119	self._SetNext()
2120
2121	self._GetWord()
2122	if self.c_id == Id.Right_ShFunction:
2123	# 'f ()' implies a function definition, since invoking it with no args
2124	# would just be 'f'
2125	self._SetNext()
2126
2127	self._NewlineOk()
2128
2129	func = command.ShFunction.CreateNull()
2130	func.name = name
2131	with ctx_VarChecker(self.var_checker, blame_tok):
2132	func.body = self.ParseCompoundCommand()
2133
2134	func.name_tok = location.LeftTokenForCompoundWord(word0)
2135	return func
2136	else:
2137	p_die('Expected ) in function definition', loc.Word(self.cur_word))
2138	return None
2139
2140	def ParseKshFunctionDef(self):
2141	# type: () -> command.ShFunction
2142	"""
2143	ksh_function_def : 'function' fname ( '(' ')' )? newline_ok function_body
2144	"""
2145	keyword_tok = word_.AsKeywordToken(self.cur_word)
2146
2147	self._SetNext() # skip past 'function'
2148	self._GetWord()
2149
2150	cur_word = cast(CompoundWord, self.cur_word) # caller ensures validity
2151	name = word_.ShFunctionName(cur_word)
2152	if len(name) == 0: # example: foo$x is invalid
2153	p_die('Invalid KSH-style function name', loc.Word(cur_word))
2154
2155	name_word = self.cur_word
2156	self._SetNext() # skip past 'function name
2157
2158	self._GetWord()
2159	if self.c_id == Id.Op_LParen:
2160	self.lexer.PushHint(Id.Op_RParen, Id.Right_ShFunction)
2161	self._SetNext()
2162	self._Eat(Id.Right_ShFunction)
2163
2164	self._NewlineOk()
2165
2166	func = command.ShFunction.CreateNull()
2167	func.name = name
2168	with ctx_VarChecker(self.var_checker, keyword_tok):
2169	func.body = self.ParseCompoundCommand()
2170
2171	func.keyword = keyword_tok
2172	func.name_tok = location.LeftTokenForWord(name_word)
2173	return func
2174
2175	def ParseYshProc(self):
2176	# type: () -> Proc
2177	node = Proc.CreateNull(alloc_lists=True)
2178
2179	keyword_tok = word_.AsKeywordToken(self.cur_word)
2180	node.keyword = keyword_tok
2181
2182	with ctx_VarChecker(self.var_checker, keyword_tok):
2183	with ctx_CmdMode(self, cmd_mode_e.Proc):
2184	self.w_parser.ParseProc(node)
2185	if node.sig.tag() == proc_sig_e.Closed: # Register params
2186	sig = cast(proc_sig.Closed, node.sig)
2187
2188	# Treat 3 kinds of params as variables.
2189	wp = sig.word
2190	if wp:
2191	for param in wp.params:
2192	self.var_checker.Check(Id.KW_Var, param.name,
2193	param.blame_tok)
2194	if wp.rest_of:
2195	r = wp.rest_of
2196	self.var_checker.Check(Id.KW_Var, r.name,
2197	r.blame_tok)
2198	# We COULD register __out here but it would require a different API.
2199	#if param.prefix and param.prefix.id == Id.Arith_Colon:
2200	# self.var_checker.Check(Id.KW_Var, '__' + param.name)
2201
2202	posit = sig.positional
2203	if posit:
2204	for param in posit.params:
2205	self.var_checker.Check(Id.KW_Var, param.name,
2206	param.blame_tok)
2207	if posit.rest_of:
2208	r = posit.rest_of
2209	self.var_checker.Check(Id.KW_Var, r.name,
2210	r.blame_tok)
2211
2212	named = sig.named
2213	if named:
2214	for param in named.params:
2215	self.var_checker.Check(Id.KW_Var, param.name,
2216	param.blame_tok)
2217	if named.rest_of:
2218	r = named.rest_of
2219	self.var_checker.Check(Id.KW_Var, r.name,
2220	r.blame_tok)
2221
2222	if sig.block_param:
2223	b = sig.block_param
2224	self.var_checker.Check(Id.KW_Var, b.name, b.blame_tok)
2225
2226	self._SetNext()
2227	node.body = self.ParseBraceGroup()
2228	# No redirects for YSH procs (only at call site)
2229
2230	return node
2231
2232	def ParseYshFunc(self):
2233	# type: () -> Func
2234	"""
2235	ysh_func: (
2236	Expr_Name '(' [func_params] [';' func_params] ')' ['=>' type_expr] '{'
2237	)
2238	Looking at KW_Func
2239	"""
2240	node = Func.CreateNull(alloc_lists=True)
2241
2242	keyword_tok = word_.AsKeywordToken(self.cur_word)
2243	node.keyword = keyword_tok
2244
2245	with ctx_VarChecker(self.var_checker, keyword_tok):
2246	self.w_parser.ParseFunc(node)
2247
2248	posit = node.positional
2249	if posit:
2250	for param in posit.params:
2251	self.var_checker.Check(Id.KW_Var, param.name,
2252	param.blame_tok)
2253	if posit.rest_of:
2254	r = posit.rest_of
2255	self.var_checker.Check(Id.KW_Var, r.name, r.blame_tok)
2256
2257	named = node.named
2258	if named:
2259	for param in named.params:
2260	self.var_checker.Check(Id.KW_Var, param.name,
2261	param.blame_tok)
2262	if named.rest_of:
2263	r = named.rest_of
2264	self.var_checker.Check(Id.KW_Var, r.name, r.blame_tok)
2265
2266	self._SetNext()
2267	with ctx_CmdMode(self, cmd_mode_e.Func):
2268	node.body = self.ParseBraceGroup()
2269
2270	return node
2271
2272	def ParseCoproc(self):
2273	# type: () -> command_t
2274	"""
2275	TODO: command.Coproc?
2276	"""
2277	raise NotImplementedError()
2278
2279	def ParseSubshell(self):
2280	# type: () -> command.Subshell
2281	"""
2282	subshell : '(' compound_list ')'
2283
2284	Looking at Op_LParen
2285	"""
2286	left = word_.AsOperatorToken(self.cur_word)
2287	self._SetNext() # skip past (
2288
2289	# Ensure that something $( (cd / && pwd) ) works. If ) is already on the
2290	# translation stack, we want to delay it.
2291
2292	self.lexer.PushHint(Id.Op_RParen, Id.Right_Subshell)
2293
2294	c_list = self._ParseCommandList()
2295	if len(c_list.children) == 1:
2296	child = c_list.children[0]
2297	else:
2298	child = c_list
2299
2300	ate = self._Eat(Id.Right_Subshell)
2301	right = word_.AsOperatorToken(ate)
2302
2303	return command.Subshell(left, child, right)
2304
2305	def ParseDBracket(self):
2306	# type: () -> command.DBracket
2307	"""Pass the underlying word parser off to the boolean expression
2308	parser."""
2309	left = word_.AsKeywordToken(self.cur_word)
2310	# TODO: Test interactive. Without closing ]], you should get > prompt
2311	# (PS2)
2312
2313	self._SetNext() # skip [[
2314	b_parser = bool_parse.BoolParser(self.w_parser)
2315	bnode, right = b_parser.Parse() # May raise
2316	return command.DBracket(left, bnode, right)
2317
2318	def ParseDParen(self):
2319	# type: () -> command.DParen
2320	left = word_.AsOperatorToken(self.cur_word)
2321
2322	self._SetNext() # skip ((
2323	anode, right = self.w_parser.ReadDParen()
2324	assert anode is not None
2325
2326	return command.DParen(left, anode, right)
2327
2328	def ParseCommand(self):
2329	# type: () -> command_t
2330	"""
2331	command : simple_command
2332	\| compound_command # OSH edit: io_redirect* folded in
2333	\| function_def
2334	\| ksh_function_def
2335
2336	# YSH extensions
2337	\| proc NAME ...
2338	\| typed proc NAME ...
2339	\| func NAME ...
2340	\| const ...
2341	\| var ...
2342	\| setglobal ...
2343	\| setref ...
2344	\| setvar ...
2345	\| call EXPR
2346	\| = EXPR
2347	;
2348
2349	Note: the reason const / var are not part of compound_command is because
2350	they can't be alone in a shell function body.
2351
2352	Example:
2353	This is valid shell f() if true; then echo hi; fi
2354	This is invalid f() var x = 1
2355	"""
2356	if self._AtSecondaryKeyword():
2357	p_die('Unexpected word when parsing command',
2358	loc.Word(self.cur_word))
2359
2360	# YSH Extensions
2361
2362	if self.c_id == Id.KW_Proc: # proc p { ... }
2363	# proc is hidden because of the 'local reasoning' principle. Code
2364	# inside procs should be YSH, full stop. That means ysh:upgrade is
2365	# on.
2366	if self.parse_opts.parse_proc():
2367	return self.ParseYshProc()
2368	else:
2369	# 2024-02: This avoids bad syntax errors if you type YSH code
2370	# into OSH
2371	# proc p (x) { echo hi } would actually be parsed as a
2372	# command.Simple! Shell compatibility: quote 'proc'
2373	p_die("proc is a YSH keyword, but this is OSH.",
2374	loc.Word(self.cur_word))
2375
2376	if self.c_id == Id.KW_Typed: # typed proc p () { ... }
2377	self._SetNext()
2378	self._GetWord()
2379	if self.c_id != Id.KW_Proc:
2380	p_die("Expected 'proc' after 'typed'", loc.Word(self.cur_word))
2381
2382	if self.parse_opts.parse_proc():
2383	return self.ParseYshProc()
2384	else:
2385	p_die("typed is a YSH keyword, but this is OSH.",
2386	loc.Word(self.cur_word))
2387
2388	if self.c_id == Id.KW_Func: # func f(x) { ... }
2389	if self.parse_opts.parse_func():
2390	return self.ParseYshFunc()
2391	else:
2392	# Same reasoning as above, for 'proc'
2393	p_die("func is a YSH keyword, but this is OSH.",
2394	loc.Word(self.cur_word))
2395
2396	if self.c_id == Id.KW_Const and self.cmd_mode != cmd_mode_e.Shell:
2397	p_die("const can't be inside proc or func. Use var instead.",
2398	loc.Word(self.cur_word))
2399
2400	if self.c_id in (Id.KW_Var, Id.KW_Const): # var x = 1
2401	keyword_id = self.c_id
2402	kw_token = word_.LiteralToken(self.cur_word)
2403	self._SetNext()
2404	n8 = self.w_parser.ParseVarDecl(kw_token)
2405	for lhs in n8.lhs:
2406	self.var_checker.Check(keyword_id, lhs.name, lhs.left)
2407	return n8
2408
2409	if self.c_id in (Id.KW_SetVar, Id.KW_SetGlobal):
2410	kw_token = word_.LiteralToken(self.cur_word)
2411	self._SetNext()
2412	n9 = self.w_parser.ParseMutation(kw_token, self.var_checker)
2413	return n9
2414
2415	if self.c_id in (Id.KW_Call, Id.Lit_Equals):
2416	# = 42 + a[i]
2417	# call mylist->append('x')
2418
2419	keyword = word_.LiteralToken(self.cur_word)
2420	assert keyword is not None
2421	self._SetNext()
2422	enode = self.w_parser.ParseCommandExpr()
2423	return command.Expr(keyword, enode)
2424
2425	if self.c_id == Id.KW_Function:
2426	return self.ParseKshFunctionDef()
2427
2428	if self.c_id in (Id.KW_DLeftBracket, Id.Op_DLeftParen, Id.Op_LParen,
2429	Id.Lit_LBrace, Id.KW_For, Id.KW_While, Id.KW_Until,
2430	Id.KW_If, Id.KW_Case, Id.KW_Time):
2431	return self.ParseCompoundCommand()
2432
2433	# Syntax error for '}' starting a line, which all shells disallow.
2434	if self.c_id == Id.Lit_RBrace:
2435	p_die('Unexpected right brace', loc.Word(self.cur_word))
2436
2437	if self.c_kind == Kind.Redir: # Leading redirect
2438	return self.ParseSimpleCommand()
2439
2440	if self.c_kind == Kind.Word:
2441	# ensured by Kind.Word
2442	cur_word = cast(CompoundWord, self.cur_word)
2443
2444	# NOTE: At the top level, only Token and Compound are possible.
2445	# Can this be modelled better in the type system, removing asserts?
2446	#
2447	# TODO: This can be a proc INVOCATION! (Doesn't even need parse_paren)
2448	# Problem: We have to distinguish f( ) { echo ; } and myproc (x, y)
2449	# That requires 2 tokens of lookahead, which we don't have
2450	#
2451	# Or maybe we don't just have ParseSimpleCommand -- we will have
2452	# ParseYshCommand or something
2453
2454	if (self.w_parser.LookAheadFuncParens() and
2455	not word_.IsVarLike(cur_word)):
2456	return self.ParseFunctionDef() # f() { echo; } # function
2457
2458	# Parse x = 1+2*3 when inside HayNode { } blocks
2459	parts = cur_word.parts
2460	if self.parse_opts.parse_equals() and len(parts) == 1:
2461	part0 = parts[0]
2462	if part0.tag() == word_part_e.Literal:
2463	tok = cast(Token, part0)
2464	if (tok.id == Id.Lit_Chars and
2465	self.w_parser.LookPastSpace() == Id.Lit_Equals and
2466	match.IsValidVarName(lexer.LazyStr(tok))):
2467
2468	if (len(self.hay_attrs_stack) and
2469	self.hay_attrs_stack[-1]):
2470	# Note: no static var_checker.Check() for bare assignment
2471	enode = self.w_parser.ParseBareDecl()
2472	self._SetNext() # Somehow this is necessary
2473	# TODO: Use BareDecl here. Well, do that when we
2474	# treat it as const or lazy.
2475	return command.VarDecl(
2476	None,
2477	[NameType(tok, lexer.TokenVal(tok), None)],
2478	enode)
2479	else:
2480	self._SetNext()
2481	self._GetWord()
2482	p_die(
2483	'Unexpected = (Hint: use var/setvar, or quote it)',
2484	loc.Word(self.cur_word))
2485
2486	# echo foo
2487	# f=(a b c) # array
2488	# array[1+2]+=1
2489	return self.ParseSimpleCommand()
2490
2491	if self.c_kind == Kind.Eof:
2492	p_die("Unexpected EOF while parsing command",
2493	loc.Word(self.cur_word))
2494
2495	# NOTE: This only happens in batch mode in the second turn of the loop!
2496	# e.g. )
2497	p_die("Invalid word while parsing command", loc.Word(self.cur_word))
2498
2499	assert False # for MyPy
2500
2501	def ParsePipeline(self):
2502	# type: () -> command_t
2503	"""
2504	pipeline : Bang? command ( '\|' newline_ok command )* ;
2505	"""
2506	negated = None # type: Optional[Token]
2507
2508	self._GetWord()
2509	if self.c_id == Id.KW_Bang:
2510	negated = word_.AsKeywordToken(self.cur_word)
2511	self._SetNext()
2512
2513	child = self.ParseCommand()
2514	assert child is not None
2515
2516	children = [child]
2517
2518	self._GetWord()
2519	if self.c_id not in (Id.Op_Pipe, Id.Op_PipeAmp):
2520	if negated is not None:
2521	node = command.Pipeline(negated, children, [])
2522	return node
2523	else:
2524	return child # no pipeline
2525
2526	# \| or \|&
2527	ops = [] # type: List[Token]
2528	while True:
2529	op = word_.AsOperatorToken(self.cur_word)
2530	ops.append(op)
2531
2532	self._SetNext() # skip past Id.Op_Pipe or Id.Op_PipeAmp
2533	self._NewlineOk()
2534
2535	child = self.ParseCommand()
2536	children.append(child)
2537
2538	self._GetWord()
2539	if self.c_id not in (Id.Op_Pipe, Id.Op_PipeAmp):
2540	break
2541
2542	return command.Pipeline(negated, children, ops)
2543
2544	def ParseAndOr(self):
2545	# type: () -> command_t
2546	self._GetWord()
2547	if self.c_id == Id.Lit_TDot:
2548	# We got '...', so parse in multiline mode
2549	self._SetNext()
2550	with word_.ctx_Multiline(self.w_parser):
2551	return self._ParseAndOr()
2552
2553	# Parse in normal mode, not multiline
2554	return self._ParseAndOr()
2555
2556	def _ParseAndOr(self):
2557	# type: () -> command_t
2558	"""
2559	and_or : and_or ( AND_IF \| OR_IF ) newline_ok pipeline
2560	\| pipeline
2561
2562	Note that it is left recursive and left associative. We parse it
2563	iteratively with a token of lookahead.
2564	"""
2565	child = self.ParsePipeline()
2566	assert child is not None
2567
2568	self._GetWord()
2569	if self.c_id not in (Id.Op_DPipe, Id.Op_DAmp):
2570	return child
2571
2572	ops = [] # type: List[Token]
2573	children = [child]
2574
2575	while True:
2576	ops.append(word_.AsOperatorToken(self.cur_word))
2577
2578	self._SetNext() # skip past \|\| &&
2579	self._NewlineOk()
2580
2581	child = self.ParsePipeline()
2582	children.append(child)
2583
2584	self._GetWord()
2585	if self.c_id not in (Id.Op_DPipe, Id.Op_DAmp):
2586	break
2587
2588	return command.AndOr(children, ops)
2589
2590	# NOTE: _ParseCommandLine and _ParseCommandTerm are similar, but different.
2591
2592	# At the top level, we execute after every line, e.g. to
2593	# - process alias (a form of dynamic parsing)
2594	# - process 'exit', because invalid syntax might appear after it
2595
2596	# On the other hand, for a while loop body, we parse the whole thing at once,
2597	# and then execute it. We don't want to parse it over and over again!
2598
2599	# COMPARE
2600	# command_line : and_or (sync_op and_or)* trailer? ; # TOP LEVEL
2601	# command_term : and_or (trailer and_or)* ; # CHILDREN
2602
2603	def _ParseCommandLine(self):
2604	# type: () -> command_t
2605	"""
2606	command_line : and_or (sync_op and_or)* trailer? ;
2607	trailer : sync_op newline_ok
2608	\| NEWLINES;
2609	sync_op : '&' \| ';';
2610
2611	NOTE: This rule causes LL(k > 1) behavior. We would have to peek to see if
2612	there is another command word after the sync op.
2613
2614	But it's easier to express imperatively. Do the following in a loop:
2615	1. ParseAndOr
2616	2. Peek.
2617	a. If there's a newline, then return. (We're only parsing a single
2618	line.)
2619	b. If there's a sync_op, process it. Then look for a newline and
2620	return. Otherwise, parse another AndOr.
2621	"""
2622	# This END_LIST is slightly different than END_LIST in _ParseCommandTerm.
2623	# I don't think we should add anything else here; otherwise it will be
2624	# ignored at the end of ParseInteractiveLine(), e.g. leading to bug #301.
2625	END_LIST = [Id.Op_Newline, Id.Eof_Real]
2626
2627	children = [] # type: List[command_t]
2628	done = False
2629	while not done:
2630	child = self.ParseAndOr()
2631
2632	self._GetWord()
2633	if self.c_id in (Id.Op_Semi, Id.Op_Amp):
2634	tok = cast(Token, self.cur_word) # for MyPy
2635	child = command.Sentence(child, tok)
2636	self._SetNext()
2637
2638	self._GetWord()
2639	if self.c_id in END_LIST:
2640	done = True
2641
2642	elif self.c_id in END_LIST:
2643	done = True
2644
2645	else:
2646	# e.g. echo a(b)
2647	p_die(
2648	'Invalid word while parsing command line (%s)' %
2649	Id_str(self.c_id), loc.Word(self.cur_word))
2650
2651	children.append(child)
2652
2653	# Simplify the AST.
2654	if len(children) > 1:
2655	return command.CommandList(children)
2656	else:
2657	return children[0]
2658
2659	def _ParseCommandTerm(self):
2660	# type: () -> command.CommandList
2661	""""
2662	command_term : and_or (trailer and_or)* ;
2663	trailer : sync_op newline_ok
2664	\| NEWLINES;
2665	sync_op : '&' \| ';';
2666
2667	This is handled in imperative style, like _ParseCommandLine.
2668	Called by _ParseCommandList for all blocks, and also for ParseCaseArm,
2669	which is slightly different. (HOW? Is it the DSEMI?)
2670
2671	Returns:
2672	syntax_asdl.command
2673	"""
2674	# Token types that will end the command term.
2675	END_LIST = [
2676	self.eof_id, Id.Right_Subshell, Id.Lit_RBrace, Id.Op_DSemi,
2677	Id.Op_SemiAmp, Id.Op_DSemiAmp
2678	]
2679
2680	# NOTE: This is similar to _ParseCommandLine.
2681	#
2682	# - Why aren't we doing END_LIST in _ParseCommandLine?
2683	# - Because you will never be inside $() at the top level.
2684	# - We also know it will end in a newline. It can't end in "fi"!
2685	# - example: if true; then { echo hi; } fi
2686
2687	children = [] # type: List[command_t]
2688	done = False
2689	while not done:
2690	# Most keywords are valid "first words". But do/done/then do not BEGIN
2691	# commands, so they are not valid.
2692	if self._AtSecondaryKeyword():
2693	break
2694
2695	child = self.ParseAndOr()
2696
2697	self._GetWord()
2698	if self.c_id == Id.Op_Newline:
2699	self._SetNext()
2700
2701	self._GetWord()
2702	if self.c_id in END_LIST:
2703	done = True
2704
2705	elif self.c_id in (Id.Op_Semi, Id.Op_Amp):
2706	tok = cast(Token, self.cur_word) # for MyPy
2707	child = command.Sentence(child, tok)
2708	self._SetNext()
2709
2710	self._GetWord()
2711	if self.c_id == Id.Op_Newline:
2712	self._SetNext() # skip over newline
2713
2714	# Test if we should keep going. There might be another command after
2715	# the semi and newline.
2716	self._GetWord()
2717	if self.c_id in END_LIST: # \n EOF
2718	done = True
2719
2720	elif self.c_id in END_LIST: # ; EOF
2721	done = True
2722
2723	elif self.c_id in END_LIST: # EOF
2724	done = True
2725
2726	# For if test -f foo; test -f bar {
2727	elif self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace:
2728	done = True
2729
2730	elif self.c_kind != Kind.Word:
2731	# e.g. f() { echo (( x )) ; }
2732	# but can't fail on 'fi fi', see osh/cmd_parse_test.py
2733
2734	#log("Invalid %s", self.cur_word)
2735	p_die("Invalid word while parsing command list",
2736	loc.Word(self.cur_word))
2737
2738	children.append(child)
2739
2740	return command.CommandList(children)
2741
2742	def _ParseCommandList(self):
2743	# type: () -> command.CommandList
2744	"""
2745	command_list : newline_ok command_term trailer? ;
2746
2747	This one is called by all the compound commands. It's basically a command
2748	block.
2749
2750	NOTE: Rather than translating the CFG directly, the code follows a style
2751	more like this: more like this: (and_or trailer)+. It makes capture
2752	easier.
2753	"""
2754	self._NewlineOk()
2755	return self._ParseCommandTerm()
2756
2757	def ParseLogicalLine(self):
2758	# type: () -> command_t
2759	"""Parse a single line for main_loop.
2760
2761	A wrapper around _ParseCommandLine(). Similar but not identical to
2762	_ParseCommandList() and ParseCommandSub().
2763
2764	Raises:
2765	ParseError
2766	"""
2767	self._NewlineOk()
2768	self._GetWord()
2769	if self.c_id == Id.Eof_Real:
2770	return None # main loop checks for here docs
2771	node = self._ParseCommandLine()
2772	return node
2773
2774	def ParseInteractiveLine(self):
2775	# type: () -> parse_result_t
2776	"""Parse a single line for Interactive main_loop.
2777
2778	Different from ParseLogicalLine because newlines are handled differently.
2779
2780	Raises:
2781	ParseError
2782	"""
2783	self._GetWord()
2784	if self.c_id == Id.Op_Newline:
2785	return parse_result.EmptyLine
2786	if self.c_id == Id.Eof_Real:
2787	return parse_result.Eof
2788
2789	node = self._ParseCommandLine()
2790	return parse_result.Node(node)
2791
2792	def ParseCommandSub(self):
2793	# type: () -> command_t
2794	"""Parse $(echo hi) and `echo hi` for word_parse.py.
2795
2796	They can have multiple lines, like this: echo $( echo one echo
2797	two )
2798	"""
2799	self._NewlineOk()
2800
2801	self._GetWord()
2802	if self.c_kind == Kind.Eof: # e.g. $()
2803	return command.NoOp
2804
2805	c_list = self._ParseCommandTerm()
2806	if len(c_list.children) == 1:
2807	return c_list.children[0]
2808	else:
2809	return c_list
2810
2811	def CheckForPendingHereDocs(self):
2812	# type: () -> None
2813	# NOTE: This happens when there is no newline at the end of a file, like
2814	# osh -c 'cat <<EOF'
2815	if len(self.pending_here_docs):
2816	node = self.pending_here_docs[0] # Just show the first one?
2817	h = cast(redir_param.HereDoc, node.arg)
2818	p_die('Unterminated here doc began here', loc.Word(h.here_begin))
2819
2820
2821	# vim: sw=4