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

170 lines, 70 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 | BashArray(List[str] strs)
74 # TODO: Switch to this more efficient representation?
75 # max_index makes append-sparse workload faster, and normal append loops too
76 | SparseArray(Dict[BigInt, str] d, BigInt max_index)
77
78 | BashAssoc(Dict[str, str] d)
79
80 # DATA model for YSH follows JSON. Note: YSH doesn't have 'undefined' and
81 # 'null' like JavaScript, just 'null'.
82 | Null
83 | Bool(bool b)
84 | Int(BigInt i)
85 #| Int(int i)
86 | Float(float f)
87 | List(List[value] items)
88 | Dict(Dict[str, value] d)
89
90 # CODE types
91 # unevaluated: Eggex, Expr, Template, Command/Block
92 # callable, in separate namespaces: Func, BoundFunc, Proc
93
94 # expr is spliced
95 # / d+; ignorecase / -> '[[:digit:]]+' REG_ICASE
96 | Eggex(re spliced, str canonical_flags,
97 List[value?] convert_funcs, List[Token?] convert_toks,
98 # str? is because some groups are not named
99 str? as_ere, List[str?] capture_names)
100
101 # The indices list has 2 * (num_group + 1) entries. Group 0 is the whole
102 # match, and each group has both a start and end index.
103 # It's flat to reduce allocations. The group() start() end() funcs/methods
104 # provide a nice interface.
105 | Match %RegexMatch
106
107 # ^[42 + a[i]]
108 | Expr(expr e)
109
110 # ^(echo 1; echo 2) and cd { echo 1; echo 2 }
111 | Command(command c)
112
113 # for Hay to get the backing lines
114 # TODO: Consolidate value.Command and value.LiteralBlock. All Command
115 # instance should have backing lines.
116
117 # TODO: ASDL doesn't support shared variant across module
118 # This would be more efficient
119 # | LiteralBlock %LiteralBlock
120 | Block(LiteralBlock block)
121
122 # A place has an additional stack frame where the value is evaluated.
123 # The frame MUST be lower on the stack at the time of use.
124 | Place(y_lvalue lval, Dict[str, Cell] frame)
125
126 # for Flags/flag and Flags/arg?
127 # for json read/write ?
128 # Possibly unify Hay and modules/namespaces
129 | Module(Dict[str, value] defs)
130
131 # The ability to use operating system functions. Right now some functions
132 # leak, like glob().
133 | IO(any cmd_ev, any prompt_ev)
134
135 # Do we need this?
136 # _guts->heapId() can be used to detect object cycles.
137 # It's considered impure; it depends on VM implementation details. The =
138 # operator and 'pp value' also print the heap ID.
139 | Guts(any vm)
140
141 # callable is vm._Callable.
142 # TODO: ASDL needs some kind of "extern" to declare vm._Callable and
143 # cmd_eval.CommandEvaluator. I think it would just generate a forward
144 # declaration.
145 | BuiltinFunc(any callable)
146 | BoundFunc(value me, value func)
147
148 # command.ShFunction and command.Proc evaluate to value.Proc
149 # They each have name, name_tok, and body.
150 #
151 # YSH procs disable dynamic scope, have default args to evaluate, and
152 # different @ARGV.
153
154 | Proc(str name, Token name_tok, proc_sig sig, command body,
155 ProcDefaults? defaults, bool sh_compat)
156
157 # module may be a frame where defined
158 | Func(str name, Func parsed,
159 List[value] pos_defaults, Dict[str, value] named_defaults,
160 Dict[str, Cell]? module_)
161
162 # a[3:5] a[:10] a[3:] a[:] # both ends are optional
163 | Slice(IntBox? lower, IntBox? upper)
164
165 # for i in (1:n) { echo $i } # both ends are required
166 | Range(int lower, int upper)
167}
168
169# vim: sw=2
170