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	# Later
1501	# < is Id.Redir_Less
1502	# > is Id.Redir_Great
1503
1504	w = self._Eat(Id.Redir_LessGreat)
1505	left = word_.AsOperatorToken(w)
1506
1507	node.iterable = for_iter.Files(left, [])
1508
1509	# We don't accept for x in <>; do ...
1510	self._GetWord()
1511	if self.c_id != Id.Lit_LBrace:
1512	p_die('Expected { after files', loc.Word(self.cur_word))
1513
1514	elif next_id == Id.Redir_Less: # for x in <> {
1515	self._Eat(Id.Redir_Less)
1516	p_die('TODO: files list', loc.Word(self.cur_word))
1517
1518	"""
1519	# We don't accept for x in < $myfile >; do ...
1520	self._GetWord()
1521	if self.c_id != Id.Lit_LBrace:
1522	p_die('Expected { after files', loc.Word(self.cur_word))
1523	"""
1524
1525	else:
1526	semi_tok = None # type: Optional[Token]
1527	iter_words, semi_tok = self.ParseForWords()
1528	node.semi_tok = semi_tok
1529
1530	if not self.parse_opts.parse_bare_word() and len(
1531	iter_words) == 1:
1532	ok, s, quoted = word_.StaticEval(iter_words[0])
1533	if ok and match.IsValidVarName(s) and not quoted:
1534	p_die(
1535	'Surround this word with either parens or quotes (parse_bare_word)',
1536	loc.Word(iter_words[0]))
1537
1538	words2 = braces.BraceDetectAll(iter_words)
1539	words3 = word_.TildeDetectAll(words2)
1540	node.iterable = for_iter.Words(words3)
1541
1542	# Now that we know there are words, do an extra check
1543	if num_iter_names > 2:
1544	p_die('Expected at most 2 loop variables', for_kw)
1545
1546	elif self.c_id == Id.KW_Do:
1547	node.iterable = for_iter.Args # implicitly loop over "$@"
1548	# do not advance
1549
1550	elif self.c_id == Id.Op_Semi: # for x; do
1551	node.iterable = for_iter.Args # implicitly loop over "$@"
1552	self._SetNext()
1553
1554	else: # for foo BAD
1555	p_die('Unexpected word after for loop variable',
1556	loc.Word(self.cur_word))
1557
1558	self._GetWord()
1559	if self.c_id == Id.Lit_LBrace: # parse_opts.parse_brace() must be on
1560	node.body = self.ParseBraceGroup()
1561	else:
1562	node.body = self.ParseDoGroup()
1563
1564	return node
1565
1566	def ParseFor(self):
1567	# type: () -> command_t
1568	"""
1569	TODO: Update the grammar
1570
1571	for_clause : For for_name newline_ok (in for_words? for_sep)? do_group ;
1572	\| For '((' ... TODO
1573	"""
1574	ate = self._Eat(Id.KW_For)
1575	for_kw = word_.AsKeywordToken(ate)
1576
1577	self._GetWord()
1578	if self.c_id == Id.Op_DLeftParen:
1579	if not self.parse_opts.parse_dparen():
1580	p_die("Bash for loops aren't allowed (parse_dparen)",
1581	loc.Word(self.cur_word))
1582
1583	# for (( i = 0; i < 10; i++)
1584	n1 = self._ParseForExprLoop(for_kw)
1585	return self._MaybeParseRedirectList(n1)
1586	else:
1587	# for x in a b; do echo hi; done
1588	n2 = self._ParseForEachLoop(for_kw)
1589	return self._MaybeParseRedirectList(n2)
1590
1591	def _ParseConditionList(self):
1592	# type: () -> condition_t
1593	"""
1594	condition_list: command_list
1595
1596	This is a helper to parse a condition list for if commands and while/until
1597	loops. It will throw a parse error if there are no conditions in the list.
1598	"""
1599	self.allow_block = False
1600	commands = self._ParseCommandList()
1601	self.allow_block = True
1602
1603	if len(commands.children) == 0:
1604	p_die("Expected a condition", loc.Word(self.cur_word))
1605
1606	return condition.Shell(commands.children)
1607
1608	def ParseWhileUntil(self, keyword):
1609	# type: (Token) -> command.WhileUntil
1610	"""
1611	while_clause : While command_list do_group ;
1612	until_clause : Until command_list do_group ;
1613	"""
1614	self._SetNext() # skip keyword
1615
1616	if (self.parse_opts.parse_paren() and
1617	self.w_parser.LookPastSpace() == Id.Op_LParen):
1618	enode = self.w_parser.ParseYshExprForCommand()
1619	cond = condition.YshExpr(enode) # type: condition_t
1620	else:
1621	cond = self._ParseConditionList()
1622
1623	# NOTE: The LSTs will be different for OSH and YSH, but the execution
1624	# should be unchanged. To be sure we should desugar.
1625	self._GetWord()
1626	if self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace:
1627	# while test -f foo {
1628	body_node = self.ParseBraceGroup() # type: command_t
1629	else:
1630	body_node = self.ParseDoGroup()
1631
1632	return command.WhileUntil(keyword, cond, body_node)
1633
1634	def ParseCaseArm(self):
1635	# type: () -> CaseArm
1636	"""
1637	case_item: '('? pattern ('\|' pattern)* ')'
1638	newline_ok command_term? trailer? ;
1639
1640	Looking at '(' or pattern
1641	"""
1642	self.lexer.PushHint(Id.Op_RParen, Id.Right_CasePat)
1643
1644	left_tok = location.LeftTokenForWord(self.cur_word) # ( or pat
1645
1646	if self.c_id == Id.Op_LParen: # Optional (
1647	self._SetNext()
1648
1649	pat_words = [] # type: List[word_t]
1650	while True:
1651	self._GetWord()
1652	if self.c_kind != Kind.Word:
1653	p_die('Expected case pattern', loc.Word(self.cur_word))
1654	pat_words.append(self.cur_word)
1655	self._SetNext()
1656
1657	self._GetWord()
1658	if self.c_id == Id.Op_Pipe:
1659	self._SetNext()
1660	else:
1661	break
1662
1663	ate = self._Eat(Id.Right_CasePat)
1664	middle_tok = word_.AsOperatorToken(ate)
1665
1666	self._NewlineOk()
1667
1668	self._GetWord()
1669	if self.c_id not in (Id.Op_DSemi, Id.Op_SemiAmp, Id.Op_DSemiAmp,
1670	Id.KW_Esac):
1671	c_list = self._ParseCommandTerm()
1672	action_children = c_list.children
1673	else:
1674	action_children = []
1675
1676	dsemi_tok = None # type: Token
1677	self._GetWord()
1678	if self.c_id == Id.KW_Esac: # missing last ;;
1679	pass
1680	elif self.c_id in (Id.Op_DSemi, Id.Op_SemiAmp, Id.Op_DSemiAmp):
1681	dsemi_tok = word_.AsOperatorToken(self.cur_word)
1682	self._SetNext()
1683	else:
1684	# Happens on EOF
1685	p_die('Expected ;; or esac', loc.Word(self.cur_word))
1686
1687	self._NewlineOk()
1688
1689	return CaseArm(left_tok, pat.Words(pat_words), middle_tok,
1690	action_children, dsemi_tok)
1691
1692	def ParseYshCaseArm(self, discriminant):
1693	# type: (Id_t) -> CaseArm
1694	"""
1695	case_item : pattern newline_ok brace_group newline_ok
1696	pattern : pat_words
1697	\| pat_exprs
1698	\| pat_eggex
1699	\| pat_else
1700	pat_words : pat_word (newline_ok '\|' newline_ok pat_word)*
1701	pat_exprs : pat_expr (newline_ok '\|' newline_ok pat_expr)*
1702	pat_word : WORD
1703	pat_eggex : '/' oil_eggex '/'
1704	pat_expr : '(' oil_expr ')'
1705	pat_else : '(' Id.KW_Else ')'
1706
1707	Looking at: 'pattern'
1708
1709	Note that the trailing `newline_ok` in `case_item` is handled by
1710	`ParseYshCase`. We do this because parsing that `newline_ok` returns
1711	the next "discriminant" for the next token, so it makes more sense to
1712	handle it there.
1713	"""
1714	left_tok = None # type: Token
1715	pattern = None # type: pat_t
1716
1717	if discriminant in (Id.Op_LParen, Id.Arith_Slash):
1718	# pat_exprs, pat_else or pat_eggex
1719	pattern, left_tok = self.w_parser.ParseYshCasePattern()
1720	else:
1721	# pat_words
1722	pat_words = [] # type: List[word_t]
1723	while True:
1724	self._GetWord()
1725	if self.c_kind != Kind.Word:
1726	p_die('Expected case pattern', loc.Word(self.cur_word))
1727	pat_words.append(self.cur_word)
1728	self._SetNext()
1729
1730	if not left_tok:
1731	left_tok = location.LeftTokenForWord(self.cur_word)
1732
1733	self._NewlineOk()
1734
1735	self._GetWord()
1736	if self.c_id == Id.Op_Pipe:
1737	self._SetNext()
1738	self._NewlineOk()
1739	else:
1740	break
1741	pattern = pat.Words(pat_words)
1742
1743	self._NewlineOk()
1744	action = self.ParseBraceGroup()
1745
1746	# The left token of the action is our "middle" token
1747	return CaseArm(left_tok, pattern, action.left, action.children,
1748	action.right)
1749
1750	def ParseYshCase(self, case_kw):
1751	# type: (Token) -> command.Case
1752	"""
1753	ysh_case : Case '(' expr ')' LBrace newline_ok ysh_case_arm* RBrace ;
1754
1755	Looking at: token after 'case'
1756	"""
1757	enode = self.w_parser.ParseYshExprForCommand()
1758	to_match = case_arg.YshExpr(enode)
1759
1760	ate = self._Eat(Id.Lit_LBrace)
1761	arms_start = word_.BraceToken(ate)
1762
1763	discriminant = self.w_parser.NewlineOkForYshCase()
1764
1765	# Note: for now, zero arms are accepted, just like POSIX case $x in esac
1766	arms = [] # type: List[CaseArm]
1767	while discriminant != Id.Op_RBrace:
1768	arm = self.ParseYshCaseArm(discriminant)
1769	arms.append(arm)
1770
1771	discriminant = self.w_parser.NewlineOkForYshCase()
1772
1773	# NewlineOkForYshCase leaves the lexer in lex_mode_e.Expr. So the '}'
1774	# token is read as an Id.Op_RBrace, but we need to store this as a
1775	# Id.Lit_RBrace.
1776	ate = self._Eat(Id.Op_RBrace)
1777	arms_end = word_.AsOperatorToken(ate)
1778	arms_end.id = Id.Lit_RBrace
1779
1780	return command.Case(case_kw, to_match, arms_start, arms, arms_end)
1781
1782	def ParseOldCase(self, case_kw):
1783	# type: (Token) -> command.Case
1784	"""
1785	case_clause : Case WORD newline_ok In newline_ok case_arm* Esac ;
1786
1787	-> Looking at WORD
1788
1789	FYI original POSIX case list, which takes pains for DSEMI
1790
1791	case_list: case_item (DSEMI newline_ok case_item)* DSEMI? newline_ok;
1792	"""
1793	self._GetWord()
1794	w = self.cur_word
1795	if not self.parse_opts.parse_bare_word():
1796	ok, s, quoted = word_.StaticEval(w)
1797	if ok and not quoted:
1798	p_die(
1799	"This is a constant string. You may want a variable like $x (parse_bare_word)",
1800	loc.Word(w))
1801
1802	if w.tag() != word_e.Compound:
1803	p_die("Expected a word to match against", loc.Word(w))
1804
1805	to_match = case_arg.Word(w)
1806	self._SetNext() # past WORD
1807
1808	self._NewlineOk()
1809
1810	ate = self._Eat(Id.KW_In)
1811	arms_start = word_.AsKeywordToken(ate)
1812
1813	self._NewlineOk()
1814
1815	arms = [] # type: List[CaseArm]
1816	while True:
1817	self._GetWord()
1818	if self.c_id == Id.KW_Esac:
1819	break
1820	# case arm should begin with a pattern word or (
1821	if self.c_kind != Kind.Word and self.c_id != Id.Op_LParen:
1822	break
1823
1824	arm = self.ParseCaseArm()
1825	arms.append(arm)
1826
1827	ate = self._Eat(Id.KW_Esac)
1828	arms_end = word_.AsKeywordToken(ate)
1829
1830	# no redirects yet
1831	return command.Case(case_kw, to_match, arms_start, arms, arms_end)
1832
1833	def ParseCase(self):
1834	# type: () -> command.Case
1835	"""
1836	case_clause : old_case # from POSIX
1837	\| ysh_case
1838	;
1839
1840	Looking at 'Case'
1841	"""
1842	case_kw = word_.AsKeywordToken(self.cur_word)
1843	self._SetNext() # past 'case'
1844
1845	if self.w_parser.LookPastSpace() == Id.Op_LParen:
1846	return self.ParseYshCase(case_kw)
1847	else:
1848	return self.ParseOldCase(case_kw)
1849
1850	def _ParseYshElifElse(self, if_node):
1851	# type: (command.If) -> None
1852	"""If test -f foo { echo foo.
1853
1854	} elif test -f bar; test -f spam { ^ we parsed up to here echo
1855	bar } else { echo none }
1856	"""
1857	arms = if_node.arms
1858
1859	while self.c_id == Id.KW_Elif:
1860	elif_kw = word_.AsKeywordToken(self.cur_word)
1861	self._SetNext() # skip elif
1862	if (self.parse_opts.parse_paren() and
1863	self.w_parser.LookPastSpace() == Id.Op_LParen):
1864	enode = self.w_parser.ParseYshExprForCommand()
1865	cond = condition.YshExpr(enode) # type: condition_t
1866	else:
1867	self.allow_block = False
1868	commands = self._ParseCommandList()
1869	self.allow_block = True
1870	cond = condition.Shell(commands.children)
1871
1872	body = self.ParseBraceGroup()
1873	self._GetWord()
1874
1875	arm = IfArm(elif_kw, cond, None, body.children, None)
1876	arms.append(arm)
1877
1878	self._GetWord()
1879	if self.c_id == Id.KW_Else:
1880	self._SetNext()
1881	body = self.ParseBraceGroup()
1882	if_node.else_action = body.children
1883
1884	def _ParseYshIf(self, if_kw, cond):
1885	# type: (Token, condition_t) -> command.If
1886	"""
1887	if test -f foo {
1888	# ^ we parsed up to here
1889	echo foo
1890	} elif test -f bar; test -f spam {
1891	echo bar
1892	} else {
1893	echo none
1894	}
1895	NOTE: If you do something like if test -n foo{, the parser keeps going, and
1896	the error is confusing because it doesn't point to the right place.
1897
1898	I think we might need strict_brace so that foo{ is disallowed. It has to
1899	be foo\{ or foo{a,b}. Or just turn that on with parse_brace? After you
1900	form ANY CompoundWord, make sure it's balanced for Lit_LBrace and
1901	Lit_RBrace? Maybe this is pre-parsing step in the WordParser?
1902	"""
1903	if_node = command.If.CreateNull(alloc_lists=True)
1904	if_node.if_kw = if_kw
1905
1906	body1 = self.ParseBraceGroup()
1907	# Every arm has 1 spid, unlike shell-style
1908	# TODO: We could get the spids from the brace group.
1909	arm = IfArm(if_kw, cond, None, body1.children, None)
1910
1911	if_node.arms.append(arm)
1912
1913	self._GetWord()
1914	if self.c_id in (Id.KW_Elif, Id.KW_Else):
1915	self._ParseYshElifElse(if_node)
1916	# the whole if node has the 'else' spid, unlike shell-style there's no 'fi'
1917	# spid because that's in the BraceGroup.
1918	return if_node
1919
1920	def _ParseElifElse(self, if_node):
1921	# type: (command.If) -> None
1922	"""
1923	else_part: (Elif command_list Then command_list)* Else command_list ;
1924	"""
1925	arms = if_node.arms
1926
1927	self._GetWord()
1928	while self.c_id == Id.KW_Elif:
1929	elif_kw = word_.AsKeywordToken(self.cur_word)
1930	self._SetNext() # past 'elif'
1931
1932	cond = self._ParseConditionList()
1933
1934	ate = self._Eat(Id.KW_Then)
1935	then_kw = word_.AsKeywordToken(ate)
1936
1937	body = self._ParseCommandList()
1938	arm = IfArm(elif_kw, cond, then_kw, body.children, then_kw)
1939
1940	arms.append(arm)
1941
1942	self._GetWord()
1943	if self.c_id == Id.KW_Else:
1944	else_kw = word_.AsKeywordToken(self.cur_word)
1945	self._SetNext() # past 'else'
1946	body = self._ParseCommandList()
1947	if_node.else_action = body.children
1948	else:
1949	else_kw = None
1950
1951	if_node.else_kw = else_kw
1952
1953	def ParseIf(self):
1954	# type: () -> command.If
1955	"""
1956	if_clause : If command_list Then command_list else_part? Fi ;
1957
1958	open : '{' \| Then
1959	close : '}' \| Fi
1960
1961	ysh_if : If ( command_list \| '(' expr ')' )
1962	open command_list else_part? close;
1963
1964	There are 2 conditionals here: parse_paren, then parse_brace
1965	"""
1966	if_node = command.If.CreateNull(alloc_lists=True)
1967	if_kw = word_.AsKeywordToken(self.cur_word)
1968	if_node.if_kw = if_kw
1969	self._SetNext() # past 'if'
1970
1971	if (self.parse_opts.parse_paren() and
1972	self.w_parser.LookPastSpace() == Id.Op_LParen):
1973	# if (x + 1)
1974	enode = self.w_parser.ParseYshExprForCommand()
1975	cond = condition.YshExpr(enode) # type: condition_t
1976	else:
1977	# if echo 1; echo 2; then
1978	# Remove ambiguity with if cd / {
1979	cond = self._ParseConditionList()
1980
1981	self._GetWord()
1982	if self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace:
1983	return self._ParseYshIf(if_kw, cond)
1984
1985	ate = self._Eat(Id.KW_Then)
1986	then_kw = word_.AsKeywordToken(ate)
1987
1988	body = self._ParseCommandList()
1989
1990	# First arm
1991	arm = IfArm(if_kw, cond, then_kw, body.children, then_kw)
1992	if_node.arms.append(arm)
1993
1994	# 2nd to Nth arm
1995	if self.c_id in (Id.KW_Elif, Id.KW_Else):
1996	self._ParseElifElse(if_node)
1997
1998	ate = self._Eat(Id.KW_Fi)
1999	if_node.fi_kw = word_.AsKeywordToken(ate)
2000
2001	return if_node
2002
2003	def ParseTime(self):
2004	# type: () -> command_t
2005	"""Time [-p] pipeline.
2006
2007	According to bash help.
2008	"""
2009	time_kw = word_.AsKeywordToken(self.cur_word)
2010	self._SetNext() # skip time
2011	pipeline = self.ParsePipeline()
2012	return command.TimeBlock(time_kw, pipeline)
2013
2014	def ParseCompoundCommand(self):
2015	# type: () -> command_t
2016	"""
2017	Refactoring: we put io_redirect* here instead of in function_body and
2018	command.
2019
2020	compound_command : brace_group io_redirect*
2021	\| subshell io_redirect*
2022	\| for_clause io_redirect*
2023	\| while_clause io_redirect*
2024	\| until_clause io_redirect*
2025	\| if_clause io_redirect*
2026	\| case_clause io_redirect*
2027
2028	# bash extensions
2029	\| time_clause
2030	\| [[ BoolExpr ]]
2031	\| (( ArithExpr ))
2032	"""
2033	self._GetWord()
2034	if self.c_id == Id.Lit_LBrace:
2035	n1 = self.ParseBraceGroup()
2036	return self._MaybeParseRedirectList(n1)
2037	if self.c_id == Id.Op_LParen:
2038	n2 = self.ParseSubshell()
2039	return self._MaybeParseRedirectList(n2)
2040
2041	if self.c_id == Id.KW_For:
2042	# Note: Redirects parsed in this call. POSIX for and bash for ((
2043	# have different nodetypes.
2044	return self.ParseFor()
2045	if self.c_id in (Id.KW_While, Id.KW_Until):
2046	keyword = word_.AsKeywordToken(self.cur_word)
2047	n3 = self.ParseWhileUntil(keyword)
2048	return self._MaybeParseRedirectList(n3)
2049
2050	if self.c_id == Id.KW_If:
2051	n4 = self.ParseIf()
2052	return self._MaybeParseRedirectList(n4)
2053
2054	if self.c_id == Id.KW_Case:
2055	n5 = self.ParseCase()
2056	return self._MaybeParseRedirectList(n5)
2057
2058	if self.c_id == Id.KW_DLeftBracket:
2059	if not self.parse_opts.parse_dbracket():
2060	p_die('Bash [[ not allowed in YSH (parse_dbracket)',
2061	loc.Word(self.cur_word))
2062	n6 = self.ParseDBracket()
2063	return self._MaybeParseRedirectList(n6)
2064	if self.c_id == Id.Op_DLeftParen:
2065	if not self.parse_opts.parse_dparen():
2066	p_die(
2067	'Bash (( not allowed in YSH (parse_dparen, see OILS-ERR-14 for wart)',
2068	loc.Word(self.cur_word))
2069	n7 = self.ParseDParen()
2070	return self._MaybeParseRedirectList(n7)
2071
2072	# bash extensions: no redirects
2073	if self.c_id == Id.KW_Time:
2074	return self.ParseTime()
2075
2076	# Happens in function body, e.g. myfunc() oops
2077	p_die(
2078	'Unexpected word while parsing compound command (%s)' %
2079	Id_str(self.c_id), loc.Word(self.cur_word))
2080	assert False # for MyPy
2081
2082	def ParseFunctionDef(self):
2083	# type: () -> command.ShFunction
2084	"""
2085	function_header : fname '(' ')'
2086	function_def : function_header newline_ok function_body ;
2087
2088	Precondition: Looking at the function name.
2089
2090	NOTE: There is an ambiguity with:
2091
2092	function foo ( echo hi ) and
2093	function foo () ( echo hi )
2094
2095	Bash only accepts the latter, though it doesn't really follow a grammar.
2096	"""
2097	word0 = cast(CompoundWord, self.cur_word) # caller ensures validity
2098	name = word_.ShFunctionName(word0)
2099	if len(name) == 0: # example: foo$x is invalid
2100	p_die('Invalid function name', loc.Word(word0))
2101
2102	part0 = word0.parts[0]
2103	# If we got a non-empty string from ShFunctionName, this should be true.
2104	assert part0.tag() == word_part_e.Literal
2105	blame_tok = cast(Token, part0) # for ctx_VarChecker
2106
2107	self._SetNext() # move past function name
2108
2109	# Must be true because of lookahead
2110	self._GetWord()
2111	assert self.c_id == Id.Op_LParen, self.cur_word
2112
2113	self.lexer.PushHint(Id.Op_RParen, Id.Right_ShFunction)
2114	self._SetNext()
2115
2116	self._GetWord()
2117	if self.c_id == Id.Right_ShFunction:
2118	# 'f ()' implies a function definition, since invoking it with no args
2119	# would just be 'f'
2120	self._SetNext()
2121
2122	self._NewlineOk()
2123
2124	func = command.ShFunction.CreateNull()
2125	func.name = name
2126	with ctx_VarChecker(self.var_checker, blame_tok):
2127	func.body = self.ParseCompoundCommand()
2128
2129	func.name_tok = location.LeftTokenForCompoundWord(word0)
2130	return func
2131	else:
2132	p_die('Expected ) in function definition', loc.Word(self.cur_word))
2133	return None
2134
2135	def ParseKshFunctionDef(self):
2136	# type: () -> command.ShFunction
2137	"""
2138	ksh_function_def : 'function' fname ( '(' ')' )? newline_ok function_body
2139	"""
2140	keyword_tok = word_.AsKeywordToken(self.cur_word)
2141
2142	self._SetNext() # skip past 'function'
2143	self._GetWord()
2144
2145	cur_word = cast(CompoundWord, self.cur_word) # caller ensures validity
2146	name = word_.ShFunctionName(cur_word)
2147	if len(name) == 0: # example: foo$x is invalid
2148	p_die('Invalid KSH-style function name', loc.Word(cur_word))
2149
2150	name_word = self.cur_word
2151	self._SetNext() # skip past 'function name
2152
2153	self._GetWord()
2154	if self.c_id == Id.Op_LParen:
2155	self.lexer.PushHint(Id.Op_RParen, Id.Right_ShFunction)
2156	self._SetNext()
2157	self._Eat(Id.Right_ShFunction)
2158
2159	self._NewlineOk()
2160
2161	func = command.ShFunction.CreateNull()
2162	func.name = name
2163	with ctx_VarChecker(self.var_checker, keyword_tok):
2164	func.body = self.ParseCompoundCommand()
2165
2166	func.keyword = keyword_tok
2167	func.name_tok = location.LeftTokenForWord(name_word)
2168	return func
2169
2170	def ParseYshProc(self):
2171	# type: () -> Proc
2172	node = Proc.CreateNull(alloc_lists=True)
2173
2174	keyword_tok = word_.AsKeywordToken(self.cur_word)
2175	node.keyword = keyword_tok
2176
2177	with ctx_VarChecker(self.var_checker, keyword_tok):
2178	with ctx_CmdMode(self, cmd_mode_e.Proc):
2179	self.w_parser.ParseProc(node)
2180	if node.sig.tag() == proc_sig_e.Closed: # Register params
2181	sig = cast(proc_sig.Closed, node.sig)
2182
2183	# Treat 3 kinds of params as variables.
2184	wp = sig.word
2185	if wp:
2186	for param in wp.params:
2187	self.var_checker.Check(Id.KW_Var, param.name,
2188	param.blame_tok)
2189	if wp.rest_of:
2190	r = wp.rest_of
2191	self.var_checker.Check(Id.KW_Var, r.name,
2192	r.blame_tok)
2193	# We COULD register __out here but it would require a different API.
2194	#if param.prefix and param.prefix.id == Id.Arith_Colon:
2195	# self.var_checker.Check(Id.KW_Var, '__' + param.name)
2196
2197	posit = sig.positional
2198	if posit:
2199	for param in posit.params:
2200	self.var_checker.Check(Id.KW_Var, param.name,
2201	param.blame_tok)
2202	if posit.rest_of:
2203	r = posit.rest_of
2204	self.var_checker.Check(Id.KW_Var, r.name,
2205	r.blame_tok)
2206
2207	named = sig.named
2208	if named:
2209	for param in named.params:
2210	self.var_checker.Check(Id.KW_Var, param.name,
2211	param.blame_tok)
2212	if named.rest_of:
2213	r = named.rest_of
2214	self.var_checker.Check(Id.KW_Var, r.name,
2215	r.blame_tok)
2216
2217	if sig.block_param:
2218	b = sig.block_param
2219	self.var_checker.Check(Id.KW_Var, b.name, b.blame_tok)
2220
2221	self._SetNext()
2222	node.body = self.ParseBraceGroup()
2223	# No redirects for YSH procs (only at call site)
2224
2225	return node
2226
2227	def ParseYshFunc(self):
2228	# type: () -> Func
2229	"""
2230	ysh_func: (
2231	Expr_Name '(' [func_params] [';' func_params] ')' ['=>' type_expr] '{'
2232	)
2233	Looking at KW_Func
2234	"""
2235	node = Func.CreateNull(alloc_lists=True)
2236
2237	keyword_tok = word_.AsKeywordToken(self.cur_word)
2238	node.keyword = keyword_tok
2239
2240	with ctx_VarChecker(self.var_checker, keyword_tok):
2241	self.w_parser.ParseFunc(node)
2242
2243	posit = node.positional
2244	if posit:
2245	for param in posit.params:
2246	self.var_checker.Check(Id.KW_Var, param.name,
2247	param.blame_tok)
2248	if posit.rest_of:
2249	r = posit.rest_of
2250	self.var_checker.Check(Id.KW_Var, r.name, r.blame_tok)
2251
2252	named = node.named
2253	if named:
2254	for param in named.params:
2255	self.var_checker.Check(Id.KW_Var, param.name,
2256	param.blame_tok)
2257	if named.rest_of:
2258	r = named.rest_of
2259	self.var_checker.Check(Id.KW_Var, r.name, r.blame_tok)
2260
2261	self._SetNext()
2262	with ctx_CmdMode(self, cmd_mode_e.Func):
2263	node.body = self.ParseBraceGroup()
2264
2265	return node
2266
2267	def ParseCoproc(self):
2268	# type: () -> command_t
2269	"""
2270	TODO: command.Coproc?
2271	"""
2272	raise NotImplementedError()
2273
2274	def ParseSubshell(self):
2275	# type: () -> command.Subshell
2276	"""
2277	subshell : '(' compound_list ')'
2278
2279	Looking at Op_LParen
2280	"""
2281	left = word_.AsOperatorToken(self.cur_word)
2282	self._SetNext() # skip past (
2283
2284	# Ensure that something $( (cd / && pwd) ) works. If ) is already on the
2285	# translation stack, we want to delay it.
2286
2287	self.lexer.PushHint(Id.Op_RParen, Id.Right_Subshell)
2288
2289	c_list = self._ParseCommandList()
2290	if len(c_list.children) == 1:
2291	child = c_list.children[0]
2292	else:
2293	child = c_list
2294
2295	ate = self._Eat(Id.Right_Subshell)
2296	right = word_.AsOperatorToken(ate)
2297
2298	return command.Subshell(left, child, right)
2299
2300	def ParseDBracket(self):
2301	# type: () -> command.DBracket
2302	"""Pass the underlying word parser off to the boolean expression
2303	parser."""
2304	left = word_.AsKeywordToken(self.cur_word)
2305	# TODO: Test interactive. Without closing ]], you should get > prompt
2306	# (PS2)
2307
2308	self._SetNext() # skip [[
2309	b_parser = bool_parse.BoolParser(self.w_parser)
2310	bnode, right = b_parser.Parse() # May raise
2311	return command.DBracket(left, bnode, right)
2312
2313	def ParseDParen(self):
2314	# type: () -> command.DParen
2315	left = word_.AsOperatorToken(self.cur_word)
2316
2317	self._SetNext() # skip ((
2318	anode, right = self.w_parser.ReadDParen()
2319	assert anode is not None
2320
2321	return command.DParen(left, anode, right)
2322
2323	def ParseCommand(self):
2324	# type: () -> command_t
2325	"""
2326	command : simple_command
2327	\| compound_command # OSH edit: io_redirect* folded in
2328	\| function_def
2329	\| ksh_function_def
2330
2331	# YSH extensions
2332	\| proc NAME ...
2333	\| typed proc NAME ...
2334	\| func NAME ...
2335	\| const ...
2336	\| var ...
2337	\| setglobal ...
2338	\| setref ...
2339	\| setvar ...
2340	\| call EXPR
2341	\| = EXPR
2342	;
2343
2344	Note: the reason const / var are not part of compound_command is because
2345	they can't be alone in a shell function body.
2346
2347	Example:
2348	This is valid shell f() if true; then echo hi; fi
2349	This is invalid f() var x = 1
2350	"""
2351	if self._AtSecondaryKeyword():
2352	p_die('Unexpected word when parsing command',
2353	loc.Word(self.cur_word))
2354
2355	# YSH Extensions
2356
2357	if self.c_id == Id.KW_Proc: # proc p { ... }
2358	# proc is hidden because of the 'local reasoning' principle. Code
2359	# inside procs should be YSH, full stop. That means ysh:upgrade is
2360	# on.
2361	if self.parse_opts.parse_proc():
2362	return self.ParseYshProc()
2363	else:
2364	# 2024-02: This avoids bad syntax errors if you type YSH code
2365	# into OSH
2366	# proc p (x) { echo hi } would actually be parsed as a
2367	# command.Simple! Shell compatibility: quote 'proc'
2368	p_die("proc is a YSH keyword, but this is OSH.",
2369	loc.Word(self.cur_word))
2370
2371	if self.c_id == Id.KW_Typed: # typed proc p () { ... }
2372	self._SetNext()
2373	self._GetWord()
2374	if self.c_id != Id.KW_Proc:
2375	p_die("Expected 'proc' after 'typed'", loc.Word(self.cur_word))
2376
2377	if self.parse_opts.parse_proc():
2378	return self.ParseYshProc()
2379	else:
2380	p_die("typed is a YSH keyword, but this is OSH.",
2381	loc.Word(self.cur_word))
2382
2383	if self.c_id == Id.KW_Func: # func f(x) { ... }
2384	if self.parse_opts.parse_func():
2385	return self.ParseYshFunc()
2386	else:
2387	# Same reasoning as above, for 'proc'
2388	p_die("func is a YSH keyword, but this is OSH.",
2389	loc.Word(self.cur_word))
2390
2391	if self.c_id == Id.KW_Const and self.cmd_mode != cmd_mode_e.Shell:
2392	p_die("const can't be inside proc or func. Use var instead.",
2393	loc.Word(self.cur_word))
2394
2395	if self.c_id in (Id.KW_Var, Id.KW_Const): # var x = 1
2396	keyword_id = self.c_id
2397	kw_token = word_.LiteralToken(self.cur_word)
2398	self._SetNext()
2399	n8 = self.w_parser.ParseVarDecl(kw_token)
2400	for lhs in n8.lhs:
2401	self.var_checker.Check(keyword_id, lhs.name, lhs.left)
2402	return n8
2403
2404	if self.c_id in (Id.KW_SetVar, Id.KW_SetGlobal):
2405	kw_token = word_.LiteralToken(self.cur_word)
2406	self._SetNext()
2407	n9 = self.w_parser.ParseMutation(kw_token, self.var_checker)
2408	return n9
2409
2410	if self.c_id in (Id.KW_Call, Id.Lit_Equals):
2411	# = 42 + a[i]
2412	# call mylist->append('x')
2413
2414	keyword = word_.LiteralToken(self.cur_word)
2415	assert keyword is not None
2416	self._SetNext()
2417	enode = self.w_parser.ParseCommandExpr()
2418	return command.Expr(keyword, enode)
2419
2420	if self.c_id == Id.KW_Function:
2421	return self.ParseKshFunctionDef()
2422
2423	if self.c_id in (Id.KW_DLeftBracket, Id.Op_DLeftParen, Id.Op_LParen,
2424	Id.Lit_LBrace, Id.KW_For, Id.KW_While, Id.KW_Until,
2425	Id.KW_If, Id.KW_Case, Id.KW_Time):
2426	return self.ParseCompoundCommand()
2427
2428	# Syntax error for '}' starting a line, which all shells disallow.
2429	if self.c_id == Id.Lit_RBrace:
2430	p_die('Unexpected right brace', loc.Word(self.cur_word))
2431
2432	if self.c_kind == Kind.Redir: # Leading redirect
2433	return self.ParseSimpleCommand()
2434
2435	if self.c_kind == Kind.Word:
2436	# ensured by Kind.Word
2437	cur_word = cast(CompoundWord, self.cur_word)
2438
2439	# NOTE: At the top level, only Token and Compound are possible.
2440	# Can this be modelled better in the type system, removing asserts?
2441	#
2442	# TODO: This can be a proc INVOCATION! (Doesn't even need parse_paren)
2443	# Problem: We have to distinguish f( ) { echo ; } and myproc (x, y)
2444	# That requires 2 tokens of lookahead, which we don't have
2445	#
2446	# Or maybe we don't just have ParseSimpleCommand -- we will have
2447	# ParseYshCommand or something
2448
2449	if (self.w_parser.LookAheadFuncParens() and
2450	not word_.IsVarLike(cur_word)):
2451	return self.ParseFunctionDef() # f() { echo; } # function
2452
2453	# Parse x = 1+2*3 when inside HayNode { } blocks
2454	parts = cur_word.parts
2455	if self.parse_opts.parse_equals() and len(parts) == 1:
2456	part0 = parts[0]
2457	if part0.tag() == word_part_e.Literal:
2458	tok = cast(Token, part0)
2459	if (tok.id == Id.Lit_Chars and
2460	self.w_parser.LookPastSpace() == Id.Lit_Equals and
2461	match.IsValidVarName(lexer.LazyStr(tok))):
2462
2463	if (len(self.hay_attrs_stack) and
2464	self.hay_attrs_stack[-1]):
2465	# Note: no static var_checker.Check() for bare assignment
2466	enode = self.w_parser.ParseBareDecl()
2467	self._SetNext() # Somehow this is necessary
2468	# TODO: Use BareDecl here. Well, do that when we
2469	# treat it as const or lazy.
2470	return command.VarDecl(
2471	None,
2472	[NameType(tok, lexer.TokenVal(tok), None)],
2473	enode)
2474	else:
2475	self._SetNext()
2476	self._GetWord()
2477	p_die(
2478	'Unexpected = (Hint: use var/setvar, or quote it)',
2479	loc.Word(self.cur_word))
2480
2481	# echo foo
2482	# f=(a b c) # array
2483	# array[1+2]+=1
2484	return self.ParseSimpleCommand()
2485
2486	if self.c_kind == Kind.Eof:
2487	p_die("Unexpected EOF while parsing command",
2488	loc.Word(self.cur_word))
2489
2490	# NOTE: This only happens in batch mode in the second turn of the loop!
2491	# e.g. )
2492	p_die("Invalid word while parsing command", loc.Word(self.cur_word))
2493
2494	assert False # for MyPy
2495
2496	def ParsePipeline(self):
2497	# type: () -> command_t
2498	"""
2499	pipeline : Bang? command ( '\|' newline_ok command )* ;
2500	"""
2501	negated = None # type: Optional[Token]
2502
2503	self._GetWord()
2504	if self.c_id == Id.KW_Bang:
2505	negated = word_.AsKeywordToken(self.cur_word)
2506	self._SetNext()
2507
2508	child = self.ParseCommand()
2509	assert child is not None
2510
2511	children = [child]
2512
2513	self._GetWord()
2514	if self.c_id not in (Id.Op_Pipe, Id.Op_PipeAmp):
2515	if negated is not None:
2516	node = command.Pipeline(negated, children, [])
2517	return node
2518	else:
2519	return child # no pipeline
2520
2521	# \| or \|&
2522	ops = [] # type: List[Token]
2523	while True:
2524	op = word_.AsOperatorToken(self.cur_word)
2525	ops.append(op)
2526
2527	self._SetNext() # skip past Id.Op_Pipe or Id.Op_PipeAmp
2528	self._NewlineOk()
2529
2530	child = self.ParseCommand()
2531	children.append(child)
2532
2533	self._GetWord()
2534	if self.c_id not in (Id.Op_Pipe, Id.Op_PipeAmp):
2535	break
2536
2537	return command.Pipeline(negated, children, ops)
2538
2539	def ParseAndOr(self):
2540	# type: () -> command_t
2541	self._GetWord()
2542	if self.c_id == Id.Lit_TDot:
2543	# We got '...', so parse in multiline mode
2544	self._SetNext()
2545	with word_.ctx_Multiline(self.w_parser):
2546	return self._ParseAndOr()
2547
2548	# Parse in normal mode, not multiline
2549	return self._ParseAndOr()
2550
2551	def _ParseAndOr(self):
2552	# type: () -> command_t
2553	"""
2554	and_or : and_or ( AND_IF \| OR_IF ) newline_ok pipeline
2555	\| pipeline
2556
2557	Note that it is left recursive and left associative. We parse it
2558	iteratively with a token of lookahead.
2559	"""
2560	child = self.ParsePipeline()
2561	assert child is not None
2562
2563	self._GetWord()
2564	if self.c_id not in (Id.Op_DPipe, Id.Op_DAmp):
2565	return child
2566
2567	ops = [] # type: List[Token]
2568	children = [child]
2569
2570	while True:
2571	ops.append(word_.AsOperatorToken(self.cur_word))
2572
2573	self._SetNext() # skip past \|\| &&
2574	self._NewlineOk()
2575
2576	child = self.ParsePipeline()
2577	children.append(child)
2578
2579	self._GetWord()
2580	if self.c_id not in (Id.Op_DPipe, Id.Op_DAmp):
2581	break
2582
2583	return command.AndOr(children, ops)
2584
2585	# NOTE: _ParseCommandLine and _ParseCommandTerm are similar, but different.
2586
2587	# At the top level, we execute after every line, e.g. to
2588	# - process alias (a form of dynamic parsing)
2589	# - process 'exit', because invalid syntax might appear after it
2590
2591	# On the other hand, for a while loop body, we parse the whole thing at once,
2592	# and then execute it. We don't want to parse it over and over again!
2593
2594	# COMPARE
2595	# command_line : and_or (sync_op and_or)* trailer? ; # TOP LEVEL
2596	# command_term : and_or (trailer and_or)* ; # CHILDREN
2597
2598	def _ParseCommandLine(self):
2599	# type: () -> command_t
2600	"""
2601	command_line : and_or (sync_op and_or)* trailer? ;
2602	trailer : sync_op newline_ok
2603	\| NEWLINES;
2604	sync_op : '&' \| ';';
2605
2606	NOTE: This rule causes LL(k > 1) behavior. We would have to peek to see if
2607	there is another command word after the sync op.
2608
2609	But it's easier to express imperatively. Do the following in a loop:
2610	1. ParseAndOr
2611	2. Peek.
2612	a. If there's a newline, then return. (We're only parsing a single
2613	line.)
2614	b. If there's a sync_op, process it. Then look for a newline and
2615	return. Otherwise, parse another AndOr.
2616	"""
2617	# This END_LIST is slightly different than END_LIST in _ParseCommandTerm.
2618	# I don't think we should add anything else here; otherwise it will be
2619	# ignored at the end of ParseInteractiveLine(), e.g. leading to bug #301.
2620	END_LIST = [Id.Op_Newline, Id.Eof_Real]
2621
2622	children = [] # type: List[command_t]
2623	done = False
2624	while not done:
2625	child = self.ParseAndOr()
2626
2627	self._GetWord()
2628	if self.c_id in (Id.Op_Semi, Id.Op_Amp):
2629	tok = cast(Token, self.cur_word) # for MyPy
2630	child = command.Sentence(child, tok)
2631	self._SetNext()
2632
2633	self._GetWord()
2634	if self.c_id in END_LIST:
2635	done = True
2636
2637	elif self.c_id in END_LIST:
2638	done = True
2639
2640	else:
2641	# e.g. echo a(b)
2642	p_die(
2643	'Invalid word while parsing command line (%s)' %
2644	Id_str(self.c_id), loc.Word(self.cur_word))
2645
2646	children.append(child)
2647
2648	# Simplify the AST.
2649	if len(children) > 1:
2650	return command.CommandList(children)
2651	else:
2652	return children[0]
2653
2654	def _ParseCommandTerm(self):
2655	# type: () -> command.CommandList
2656	""""
2657	command_term : and_or (trailer and_or)* ;
2658	trailer : sync_op newline_ok
2659	\| NEWLINES;
2660	sync_op : '&' \| ';';
2661
2662	This is handled in imperative style, like _ParseCommandLine.
2663	Called by _ParseCommandList for all blocks, and also for ParseCaseArm,
2664	which is slightly different. (HOW? Is it the DSEMI?)
2665
2666	Returns:
2667	syntax_asdl.command
2668	"""
2669	# Token types that will end the command term.
2670	END_LIST = [
2671	self.eof_id, Id.Right_Subshell, Id.Lit_RBrace, Id.Op_DSemi,
2672	Id.Op_SemiAmp, Id.Op_DSemiAmp
2673	]
2674
2675	# NOTE: This is similar to _ParseCommandLine.
2676	#
2677	# - Why aren't we doing END_LIST in _ParseCommandLine?
2678	# - Because you will never be inside $() at the top level.
2679	# - We also know it will end in a newline. It can't end in "fi"!
2680	# - example: if true; then { echo hi; } fi
2681
2682	children = [] # type: List[command_t]
2683	done = False
2684	while not done:
2685	# Most keywords are valid "first words". But do/done/then do not BEGIN
2686	# commands, so they are not valid.
2687	if self._AtSecondaryKeyword():
2688	break
2689
2690	child = self.ParseAndOr()
2691
2692	self._GetWord()
2693	if self.c_id == Id.Op_Newline:
2694	self._SetNext()
2695
2696	self._GetWord()
2697	if self.c_id in END_LIST:
2698	done = True
2699
2700	elif self.c_id in (Id.Op_Semi, Id.Op_Amp):
2701	tok = cast(Token, self.cur_word) # for MyPy
2702	child = command.Sentence(child, tok)
2703	self._SetNext()
2704
2705	self._GetWord()
2706	if self.c_id == Id.Op_Newline:
2707	self._SetNext() # skip over newline
2708
2709	# Test if we should keep going. There might be another command after
2710	# the semi and newline.
2711	self._GetWord()
2712	if self.c_id in END_LIST: # \n EOF
2713	done = True
2714
2715	elif self.c_id in END_LIST: # ; EOF
2716	done = True
2717
2718	elif self.c_id in END_LIST: # EOF
2719	done = True
2720
2721	# For if test -f foo; test -f bar {
2722	elif self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace:
2723	done = True
2724
2725	elif self.c_kind != Kind.Word:
2726	# e.g. f() { echo (( x )) ; }
2727	# but can't fail on 'fi fi', see osh/cmd_parse_test.py
2728
2729	#log("Invalid %s", self.cur_word)
2730	p_die("Invalid word while parsing command list",
2731	loc.Word(self.cur_word))
2732
2733	children.append(child)
2734
2735	return command.CommandList(children)
2736
2737	def _ParseCommandList(self):
2738	# type: () -> command.CommandList
2739	"""
2740	command_list : newline_ok command_term trailer? ;
2741
2742	This one is called by all the compound commands. It's basically a command
2743	block.
2744
2745	NOTE: Rather than translating the CFG directly, the code follows a style
2746	more like this: more like this: (and_or trailer)+. It makes capture
2747	easier.
2748	"""
2749	self._NewlineOk()
2750	return self._ParseCommandTerm()
2751
2752	def ParseLogicalLine(self):
2753	# type: () -> command_t
2754	"""Parse a single line for main_loop.
2755
2756	A wrapper around _ParseCommandLine(). Similar but not identical to
2757	_ParseCommandList() and ParseCommandSub().
2758
2759	Raises:
2760	ParseError
2761	"""
2762	self._NewlineOk()
2763	self._GetWord()
2764	if self.c_id == Id.Eof_Real:
2765	return None # main loop checks for here docs
2766	node = self._ParseCommandLine()
2767	return node
2768
2769	def ParseInteractiveLine(self):
2770	# type: () -> parse_result_t
2771	"""Parse a single line for Interactive main_loop.
2772
2773	Different from ParseLogicalLine because newlines are handled differently.
2774
2775	Raises:
2776	ParseError
2777	"""
2778	self._GetWord()
2779	if self.c_id == Id.Op_Newline:
2780	return parse_result.EmptyLine
2781	if self.c_id == Id.Eof_Real:
2782	return parse_result.Eof
2783
2784	node = self._ParseCommandLine()
2785	return parse_result.Node(node)
2786
2787	def ParseCommandSub(self):
2788	# type: () -> command_t
2789	"""Parse $(echo hi) and `echo hi` for word_parse.py.
2790
2791	They can have multiple lines, like this: echo $( echo one echo
2792	two )
2793	"""
2794	self._NewlineOk()
2795
2796	self._GetWord()
2797	if self.c_kind == Kind.Eof: # e.g. $()
2798	return command.NoOp
2799
2800	c_list = self._ParseCommandTerm()
2801	if len(c_list.children) == 1:
2802	return c_list.children[0]
2803	else:
2804	return c_list
2805
2806	def CheckForPendingHereDocs(self):
2807	# type: () -> None
2808	# NOTE: This happens when there is no newline at the end of a file, like
2809	# osh -c 'cat <<EOF'
2810	if len(self.pending_here_docs):
2811	node = self.pending_here_docs[0] # Just show the first one?
2812	h = cast(redir_param.HereDoc, node.arg)
2813	p_die('Unterminated here doc began here', loc.Word(h.here_begin))
2814
2815
2816	# vim: sw=4