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

167 lines, 69 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 # Methods on state.Mem return value.Undef, but it's not visible in YSH.
65 #
66 # A var bound to Undef is different than no binding because of dynamic
67 # scope. Undef can shadow values lower on the stack.
68 Undef
69
70 | Str(str s)
71
72 # "holes" in the array are represented by None
73 # TODO: Use Dict[int, str] representation
74 | BashArray(List[str] strs)
75 | BashAssoc(Dict[str, str] d)
76
77 # DATA model for YSH follows JSON. Note: YSH doesn't have 'undefined' and
78 # 'null' like JavaScript, just 'null'.
79 | Null
80 | Bool(bool b)
81 | Int(BigInt i)
82 #| Int(int i)
83 | Float(float f)
84 | List(List[value] items)
85 | Dict(Dict[str, value] d)
86
87 # CODE types
88 # unevaluated: Eggex, Expr, Template, Command/Block
89 # callable, in separate namespaces: Func, BoundFunc, Proc
90
91 # expr is spliced
92 # / d+; ignorecase / -> '[[:digit:]]+' REG_ICASE
93 | Eggex(re spliced, str canonical_flags,
94 List[value?] convert_funcs, List[Token?] convert_toks,
95 # str? is because some groups are not named
96 str? as_ere, List[str?] capture_names)
97
98 # The indices list has 2 * (num_group + 1) entries. Group 0 is the whole
99 # match, and each group has both a start and end index.
100 # It's flat to reduce allocations. The group() start() end() funcs/methods
101 # provide a nice interface.
102 | Match %RegexMatch
103
104 # ^[42 + a[i]]
105 | Expr(expr e)
106
107 # ^(echo 1; echo 2) and cd { echo 1; echo 2 }
108 | Command(command c)
109
110 # for Hay to get the backing lines
111 # TODO: Consolidate value.Command and value.LiteralBlock. All Command
112 # instance should have backing lines.
113
114 # TODO: ASDL doesn't support shared variant across module
115 # This would be more efficient
116 # | LiteralBlock %LiteralBlock
117 | Block(LiteralBlock block)
118
119 # A place has an additional stack frame where the value is evaluated.
120 # The frame MUST be lower on the stack at the time of use.
121 | Place(y_lvalue lval, Dict[str, Cell] frame)
122
123 # for Flags/flag and Flags/arg?
124 # for json read/write ?
125 # Possibly unify Hay and modules/namespaces
126 | Module(Dict[str, value] defs)
127
128 # The ability to use operating system functions. Right now some functions
129 # leak, like glob().
130 | IO(any cmd_ev, any prompt_ev)
131
132 # Do we need this?
133 # _guts->heapId() can be used to detect object cycles.
134 # It's considered impure; it depends on VM implementation details. The =
135 # operator and 'pp value' also print the heap ID.
136 | Guts(any vm)
137
138 # callable is vm._Callable.
139 # TODO: ASDL needs some kind of "extern" to declare vm._Callable and
140 # cmd_eval.CommandEvaluator. I think it would just generate a forward
141 # declaration.
142 | BuiltinFunc(any callable)
143 | BoundFunc(value me, value func)
144
145 # command.ShFunction and command.Proc evaluate to value.Proc
146 # They each have name, name_tok, and body.
147 #
148 # YSH procs disable dynamic scope, have default args to evaluate, and
149 # different @ARGV.
150
151 | Proc(str name, Token name_tok, proc_sig sig, command body,
152 ProcDefaults? defaults, bool sh_compat)
153
154 # module may be a frame where defined
155 | Func(str name, Func parsed,
156 List[value] pos_defaults, Dict[str, value] named_defaults,
157 Dict[str, Cell]? module_)
158
159 # a[3:5] a[:10] a[3:] a[:] # both ends are optional
160 | Slice(IntBox? lower, IntBox? upper)
161
162 # for i in (1:n) { echo $i } # both ends are required
163 | Range(int lower, int upper)
164}
165
166# vim: sw=2
167