OILS / core / value.asdl View on Github | oilshell.org

175 lines, 72 significant
1# Runtime value
2
3module value
4{
5 # import from frontend/syntax.asdl
6 use frontend syntax {
7 loc Token
8 expr command
9 DoubleQuoted
10 re proc_sig
11 LiteralBlock Func
12 NameType
13 EggexFlag
14 }
15
16 use core runtime {
17 Cell
18 }
19
20 IntBox = (int i)
21
22 ProcDefaults = (
23 List[value]? for_word, # all of them are value.Str
24 List[value]? for_typed,
25 Dict[str, value]? for_named,
26 value? for_block,
27 )
28
29 LeftName = (str name, loc blame_loc)
30
31 # for setvar, and value.Place
32 y_lvalue =
33 # e.g. read (&x)
34 Local %LeftName
35 # e.g. &a[0][1].key -- we evaluate a[0][1] first
36 | Container(value obj, value index)
37
38 # An sh_lvalue is for things mutation that happen with dynamic scope
39 #
40 # - sh_expr_eval uses this for unset / printf -v
41 # - word_eval uses this for ${a[0]=}
42 # - expr_eval / cmd_eval use this for setvar a[i] = 42
43 sh_lvalue =
44 Var %LeftName
45 | Indexed(str name, int index, loc blame_loc)
46 | Keyed(str name, str key, loc blame_loc)
47
48 eggex_ops =
49 # for BASH_REMATCH or ~ with a string
50 No
51 # These lists are indexed by group number, and will have None entries
52 | Yes(List[value?] convert_funcs, List[Token?] convert_toks,
53 List[str?] capture_names)
54
55 RegexMatch = (str s, List[int] indices, eggex_ops ops)
56
57 regex_match =
58 No
59 | Yes %RegexMatch
60
61 # Commands, words, and expressions from syntax.asdl are evaluated to a VALUE.
62 # value_t instances are stored in state.Mem().
63 value =
64 # Only used for val_ops.StdinIterator. (It would be nice if we could
65 # express iter_value.{Eof,Interrupted,Str,Int,...} in ASDL)
66 Interrupted
67 | Stdin
68
69 # Methods on state.Mem return value.Undef, but it's not visible in YSH.
70 #
71 # A var bound to Undef is different than no binding because of dynamic
72 # scope. Undef can shadow values lower on the stack.
73 | Undef
74
75 | Str(str s)
76
77 # "holes" in the array are represented by None
78 | BashArray(List[str] strs)
79 # TODO: Switch to this more efficient representation?
80 # max_index makes append-sparse workload faster, and normal append loops too
81 | SparseArray(Dict[BigInt, str] d, BigInt max_index)
82
83 | BashAssoc(Dict[str, str] d)
84
85 # DATA model for YSH follows JSON. Note: YSH doesn't have 'undefined' and
86 # 'null' like JavaScript, just 'null'.
87 | Null
88 | Bool(bool b)
89 | Int(BigInt i)
90 #| Int(int i)
91 | Float(float f)
92 | List(List[value] items)
93 | Dict(Dict[str, value] d)
94
95 # CODE types
96 # unevaluated: Eggex, Expr, Template, Command/Block
97 # callable, in separate namespaces: Func, BoundFunc, Proc
98
99 # expr is spliced
100 # / d+; ignorecase / -> '[[:digit:]]+' REG_ICASE
101 | Eggex(re spliced, str canonical_flags,
102 List[value?] convert_funcs, List[Token?] convert_toks,
103 # str? is because some groups are not named
104 str? as_ere, List[str?] capture_names)
105
106 # The indices list has 2 * (num_group + 1) entries. Group 0 is the whole
107 # match, and each group has both a start and end index.
108 # It's flat to reduce allocations. The group() start() end() funcs/methods
109 # provide a nice interface.
110 | Match %RegexMatch
111
112 # ^[42 + a[i]]
113 | Expr(expr e)
114
115 # ^(echo 1; echo 2) and cd { echo 1; echo 2 }
116 | Command(command c)
117
118 # for Hay to get the backing lines
119 # TODO: Consolidate value.Command and value.LiteralBlock. All Command
120 # instance should have backing lines.
121
122 # TODO: ASDL doesn't support shared variant across module
123 # This would be more efficient
124 # | LiteralBlock %LiteralBlock
125 | Block(LiteralBlock block)
126
127 # A place has an additional stack frame where the value is evaluated.
128 # The frame MUST be lower on the stack at the time of use.
129 | Place(y_lvalue lval, Dict[str, Cell] frame)
130
131 # for Flags/flag and Flags/arg?
132 # for json read/write ?
133 # Possibly unify Hay and modules/namespaces
134 | Module(Dict[str, value] defs)
135
136 # The ability to use operating system functions. Right now some functions
137 # leak, like glob().
138 | IO(any cmd_ev, any prompt_ev)
139
140 # Do we need this?
141 # _guts->heapId() can be used to detect object cycles.
142 # It's considered impure; it depends on VM implementation details. The =
143 # operator and 'pp value' also print the heap ID.
144 | Guts(any vm)
145
146 # callable is vm._Callable.
147 # TODO: ASDL needs some kind of "extern" to declare vm._Callable and
148 # cmd_eval.CommandEvaluator. I think it would just generate a forward
149 # declaration.
150 | BuiltinFunc(any callable)
151 | BoundFunc(value me, value func)
152
153 # command.ShFunction and command.Proc evaluate to value.Proc
154 # They each have name, name_tok, and body.
155 #
156 # YSH procs disable dynamic scope, have default args to evaluate, and
157 # different @ARGV.
158
159 | Proc(str name, Token name_tok, proc_sig sig, command body,
160 ProcDefaults? defaults, bool sh_compat)
161
162 # module may be a frame where defined
163 | Func(str name, Func parsed,
164 List[value] pos_defaults, Dict[str, value] named_defaults,
165 Dict[str, Cell]? module_)
166
167 # a[3:5] a[:10] a[3:] a[:] # both ends are optional
168 | Slice(IntBox? lower, IntBox? upper)
169
170 # for i in (1:n) { echo $i } # both ends are required
171 | Range(int lower, int upper)
172}
173
174# vim: sw=2
175