| 1 | # Runtime value
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| 2 |
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| 3 | module value
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| 4 | {
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| 5 | # import from frontend/syntax.asdl
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| 6 | use frontend syntax {
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| 7 | loc Token
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| 8 | expr command
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| 9 | DoubleQuoted
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| 10 | re proc_sig
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| 11 | Func
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| 12 | NameType
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| 13 | EggexFlag
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| 14 | BraceGroup SourceLine
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| 15 | }
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| 16 |
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| 17 | use core runtime {
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| 18 | Cell
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| 19 | }
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| 20 |
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| 21 | IntBox = (int i)
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| 22 |
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| 23 | ProcDefaults = (
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| 24 | List[value]? for_word, # all of them are value.Str
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| 25 | List[value]? for_typed,
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| 26 | Dict[str, value]? for_named,
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| 27 | value? for_block,
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| 28 | )
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| 29 |
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| 30 | LeftName = (str name, loc blame_loc)
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| 31 |
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| 32 | # for setvar, and value.Place
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| 33 | y_lvalue =
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| 34 | # e.g. read (&x)
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| 35 | Local %LeftName
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| 36 | # e.g. &a[0][1].key -- we evaluate a[0][1] first
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| 37 | | Container(value obj, value index)
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| 38 |
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| 39 | # An sh_lvalue is for things mutation that happen with dynamic scope
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| 40 | #
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| 41 | # - sh_expr_eval uses this for unset / printf -v
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| 42 | # - word_eval uses this for ${a[0]=}
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| 43 | # - expr_eval / cmd_eval use this for setvar a[i] = 42
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| 44 | sh_lvalue =
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| 45 | Var %LeftName
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| 46 | | Indexed(str name, int index, loc blame_loc)
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| 47 | | Keyed(str name, str key, loc blame_loc)
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| 48 |
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| 49 | eggex_ops =
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| 50 | # for BASH_REMATCH or ~ with a string
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| 51 | No
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| 52 | # These lists are indexed by group number, and will have None entries
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| 53 | | Yes(List[value?] convert_funcs, List[Token?] convert_toks,
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| 54 | List[str?] capture_names)
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| 55 |
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| 56 | RegexMatch = (str s, List[int] indices, eggex_ops ops)
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| 57 |
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| 58 | regex_match =
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| 59 | No
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| 60 | | Yes %RegexMatch
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| 61 |
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| 62 | # Retain references to lines
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| 63 | LiteralBlock = (BraceGroup brace_group, List[SourceLine] lines)
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| 64 |
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| 65 | # TODO: should Expr also have backing lines?
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| 66 | cmd_frag =
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| 67 | LiteralBlock %LiteralBlock # p { echo hi } has backing lines
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| 68 | | Expr(command c) # var b = ^(echo hi)
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| 69 |
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| 70 | # Arbitrary objects, where attributes are looked up on the prototype chain.
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| 71 | Obj = (Obj? prototype, Dict[str, value] d)
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| 72 |
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| 73 | # Commands, words, and expressions from syntax.asdl are evaluated to a VALUE.
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| 74 | # value_t instances are stored in state.Mem().
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| 75 | value =
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| 76 | #
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| 77 | # Implementation details
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| 78 | #
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| 79 |
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| 80 | # Only used for io.stdin aka val_ops.StdinIterator. (It would be nice if
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| 81 | # we could express iter_value.{Eof,Interrupted,Str,Int,...} in ASDL)
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| 82 | Interrupted
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| 83 | | Stdin
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| 84 | # Can't be instantiated by users
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| 85 | # a[3:5] a[:10] a[3:] a[:] # both ends are optional
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| 86 | | Slice(IntBox? lower, IntBox? upper)
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| 87 |
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| 88 | #
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| 89 | # OSH/Bash types
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| 90 | #
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| 91 |
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| 92 | # Methods on state::Mem return value.Undef, but it's not visible in YSH.
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| 93 | # Note: A var bound to Undef is different than no binding because of
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| 94 | # dynamic scope. Undef can shadow values lower on the stack.
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| 95 | | Undef
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| 96 |
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| 97 | | Str(str s)
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| 98 |
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| 99 | # "holes" in the array are represented by None
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| 100 | | BashArray(List[str] strs)
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| 101 | # TODO: Switch to this more efficient representation. max_index makes
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| 102 | # append-sparse workload faster, and normal append loops too
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| 103 | | SparseArray(Dict[BigInt, str] d, BigInt max_index)
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| 104 |
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| 105 | | BashAssoc(Dict[str, str] d)
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| 106 |
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| 107 | # The DATA model for YSH follows JSON. Note: YSH doesn't have 'undefined'
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| 108 | # and 'null' like JavaScript, just 'null'.
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| 109 | | Null
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| 110 | | Bool(bool b)
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| 111 | | Int(BigInt i)
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| 112 | | Float(float f)
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| 113 | | List(List[value] items)
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| 114 | | Dict(Dict[str, value] d)
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| 115 |
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| 116 | # Possible types
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| 117 | # value.Htm8 - a string that can be queried, with lazily materialized "views"
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| 118 | # value.Tsv8 - ditto
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| 119 | # value.Json8 - some kind of jq or JSONPath query language
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| 120 |
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| 121 | # Objects are for for polymorphism
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| 122 | | Obj %Obj
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| 123 |
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| 124 | # for i in (0 .. n) { echo $i } # both ends are required
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| 125 | # TODO: BigInt
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| 126 | | Range(int lower, int upper)
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| 127 |
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| 128 | # expr is spliced
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| 129 | # / d+; ignorecase / -> '[[:digit:]]+' REG_ICASE
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| 130 | | Eggex(re spliced, str canonical_flags,
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| 131 | List[value?] convert_funcs, List[Token?] convert_toks,
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| 132 | # str? is because some groups are not named
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| 133 | str? as_ere, List[str?] capture_names)
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| 134 |
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| 135 | # The indices list has 2 * (num_group + 1) entries. Group 0 is the whole
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| 136 | # match, and each group has both a start and end index.
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| 137 | # It's flat to reduce allocations. The group() start() end() funcs/methods
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| 138 | # provide a nice interface.
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| 139 | | Match %RegexMatch
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| 140 |
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| 141 | # A place has an additional stack frame where the value is evaluated.
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| 142 | # The frame MUST be lower on the stack at the time of use.
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| 143 | | Place(y_lvalue lval, Dict[str, Cell] frame)
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| 144 |
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| 145 | # for io->evalToDict(), which uses ctx_FrontFrame(), which is distinct from
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| 146 | # ctx_Eval()
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| 147 | # TODO: ASDL should let us "collapse" this Dict directly into value_t
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| 148 | | Frame(Dict[str, Cell] frame)
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| 149 |
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| 150 | #
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| 151 | # Code units: BoundFunc, BuiltinFunc, Func, BuiltinProc, Proc
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| 152 | #
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| 153 |
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| 154 | # for obj.method and obj->mutatingMethod
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| 155 | | BoundFunc(value me, value func)
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| 156 | # callable is vm._Callable.
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| 157 | # TODO: ASDL needs some kind of "extern" to declare vm._Callable,
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| 158 | # vm._Builtin. I think it would just generate a forward declaration.
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| 159 | | BuiltinFunc(any callable)
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| 160 |
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| 161 | | Func(str name, Func parsed,
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| 162 | List[value] pos_defaults, Dict[str, value] named_defaults,
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| 163 | # module is where "global" lookups happen
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| 164 | Dict[str, Cell] module_frame)
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| 165 |
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| 166 | # command.ShFunction and command.Proc evaluate to value.Proc
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| 167 | # They each have name, name_tok, and body.
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| 168 | #
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| 169 | # YSH procs disable dynamic scope, have default args to evaluate, and
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| 170 | # different @ARGV.
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| 171 |
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| 172 | # builtin is vm._Builtin, this can be introspected
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| 173 | | BuiltinProc(any builtin)
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| 174 | | Proc(str name, Token name_tok, proc_sig sig, command body,
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| 175 | ProcDefaults? defaults, bool sh_compat,
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| 176 | # module is where "global" lookups happen
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| 177 | Dict[str, Cell] module_frame)
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| 178 |
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| 179 | #
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| 180 | # Unevaluated CODE types: ExprFrag, Expr, CommandFrag, Command
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| 181 | #
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| 182 |
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| 183 | # This can be the output of parseExpr()?
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| 184 | #| ExprFrag(expr e)
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| 185 |
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| 186 | # var x = ^[42 + a[i]]
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| 187 | # my-ls | where [size > 10]
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| 188 | | Expr(expr e, Dict[str, Cell] captured_frame)
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| 189 |
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| 190 | # This is an UNBOUND command, like
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| 191 | # ^(echo 1; echo 2) and cd { echo 1; echo 2 }
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| 192 | | CommandFrag(command c)
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| 193 |
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| 194 | # Bound command
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| 195 | | Command(cmd_frag frag, Dict[str, Cell] captured_frame)
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| 196 |
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| 197 | # Other introspection
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| 198 | # __builtins__ - Dict[str, value_t] - I would like to make this read-only
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| 199 | # __modules__ - Dict[str, Obj] - read-only to prevent non-Obj
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| 200 | # __sh_funcs__ - Dict[str, value.Proc] - read-only to prevent non-Proc
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| 201 | # __traps__ - Dict[str, command_t] ?
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| 202 | # __builtin_procs__ - Dict[str, BuiltinProc] - builtin commands - special
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| 203 | # and non-special? and assignment?
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| 204 | # __aliases__ - Dict[str, str]
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| 205 | # __jobs__ - maybe nicer that jobs -p
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| 206 | # __stack__ - replaces pp stacks_, frame_vars_
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| 207 | #
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| 208 | # More:
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| 209 | # - dir stack pushd/popd - read-only variable
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| 210 | # - there is a hidden mem.pwd, in addition to $PWD
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| 211 | # - completion hooks and spec
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| 212 | # - getopts state
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| 213 | # - command cache - hash builtin
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| 214 | }
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| 215 |
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| 216 | # vim: sw=2
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| 217 |
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