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1# Data types for the Oils AST, aka "Lossless Syntax Tree".
2#
3# Invariant: the source text can be reconstructed byte-for-byte from this tree.
4# The test/lossless.sh suite verifies this.
5
6# We usually try to preserve the physical order of the source in the ASDL
7# fields. One exception is the order of redirects:
8#
9# echo >out.txt hi
10# # versus
11# echo hi >out.txt
12
13# Unrepresented:
14# - let arithmetic (rarely used)
15# - coprocesses # one with arg and one without
16# - select block
17
18# Possible refactorings:
19#
20# # %CompoundWord as first class variant:
21# bool_expr = WordTest %CompoundWord | ...
22#
23# # Can DoubleQuoted have a subset of parts compared with CompoundWord?
24# string_part = ... # subset of word_part
25#
26# - Distinguish word_t with BracedTree vs. those without? seq_word_t?
27
28module syntax
29{
30 use core value {
31 value LiteralBlock
32 }
33
34 # More efficient than the List[bool] pattern we've been using
35 BoolParamBox = (bool b)
36 IntParamBox = (int i)
37
38 # core/main_loop.py
39 parse_result = EmptyLine | Eof | Node(command cmd)
40
41 # 'source' represents the location of a line / token.
42 source =
43 Interactive
44 | Headless
45 | Unused(str comment) # completion and history never show parse errors?
46 | CFlag
47 | Stdin(str comment)
48
49 # MainFile is for main.{osh,ysh}, as well as oshrc/yshrc. They're files
50 # loaded directly by the shell.
51 | MainFile(str path)
52 # A file loaded by 'source' or 'use'.
53 # TODO: provide a chain of locations back to the sourced script! I guess
54 # the debug_stack can do that too.
55 | OtherFile(str path, loc location)
56
57 # Code parsed from a word. (TODO: rename source.Word?)
58 # used for 'eval arg', 'trap arg', 'printf arg',
59 # parseCommand() - this is a string?
60 # dynamic LHS - move this to Reparsed?
61 # complete -W
62 | Dynamic(str what, loc location)
63
64 # Point to the original variable reference
65 | VarRef(Token orig_tok)
66
67 # code parsed from the value of a variable
68 # used for $PS1 $PROMPT_COMMAND
69 | Variable(str var_name, loc location)
70
71 # alias expansion (location of first word)
72 | Alias(str argv0, loc argv0_loc)
73
74 # 2 kinds of reparsing: backticks, and x+1 in a[x+1]=y
75 | Reparsed(str what, Token left_token, Token right_token)
76
77 # For --location-str
78 | Synthetic(str s)
79
80 SourceLine = (int line_num, str content, source src)
81
82 # Note that ASDL generates:
83 # typedef uint16_t Id_t;
84 # So Token is
85 # 8 bytes GC header + 2 + 2 + 4 + 8 + 8 = 32 bytes on 64-bit machines
86 #
87 # We transpose (id, col, length) -> (id, length, col) for C struct packing.
88 Token = (id id, uint16 length, int col, SourceLine? line, str? tval)
89
90 # I wanted to get rid of Token.tval with this separate WideToken type, but it
91 # is more efficient if word_part.Literal %Token literally is the same thing
92 # that comes out of the lexer. Otherwise we have extra garbage.
93
94 # WideToken = (id id, int length, int col, SourceLine? line, str? tval)
95
96 # Slight ASDL bug: CompoundWord has to be defined before using it as a shared
97 # variant. The _product_counter algorithm should be moved into a separate
98 # tag-assigning pass, and shared between gen_python.py and gen_cpp.py.
99 CompoundWord = (List[word_part] parts)
100
101 # Source location for errors
102 loc =
103 Missing # equivalent of runtime.NO_SPID
104 | Token %Token
105 # Very common case: argv arrays need original location
106 | ArgWord %CompoundWord
107 | WordPart(word_part p)
108 | Word(word w)
109 | Arith(arith_expr a)
110 # e.g. for errexit blaming
111 | Command(command c)
112 # the location of a token that's too long
113 | TokenTooLong(SourceLine line, id id, int length, int col)
114
115 # debug_frame_t is an EXECUTION stack (proc func source use eval), while
116 # source_t (in some cases) is like a PARSING stack (files, strings from vars,
117 # etc.)
118 debug_frame =
119 # OSH: main_filename => BASH_SOURCE
120 MainFile(str main_filename)
121 # YSH
122 | Dummy # -c or stdin, not used by BASH_* vars
123 # Note: we could have more "frame 0" than MainFile and Dummy -
124 # - Completion hooks - dev.Tracer is missing these
125 # - PS1
126 # - PROMPT_COMMAND
127
128 # OSH: call_tok => BASH_LINENO, source_name => BASH_SOURCE
129 | Source(CompoundWord source_loc, str source_name)
130
131 # OSH: call_tok => BASH_LINENO, def_tok => BASH_SOURCE
132 # YSH: procs
133 | ProcLike(CompoundWord invoke_loc, Token def_tok, str proc_name)
134
135 # for io->eval, myfunc()
136 | Token %Token
137
138 # For 'eval', 'use', ...
139 | CompoundWord %CompoundWord
140
141 # Special frame added when running 'trap ERR', for more info, and as a sentinel
142 | BeforeErrTrap(Token tok)
143
144 #
145 # Shell language
146 #
147
148 bracket_op =
149 WholeArray(id op_id) # * or @
150 | ArrayIndex(arith_expr expr)
151
152 suffix_op =
153 Nullary %Token # ${x@Q} or ${!prefix@} (which also has prefix_op)
154 | Unary(Token op, rhs_word arg_word) # e.g. ${v:-default}
155 # TODO: Implement YSH ${x|html} and ${x %.3f}
156 | Static(Token tok, str arg)
157 | PatSub(CompoundWord pat, rhs_word replace, id replace_mode, Token slash_tok)
158 # optional begin is arith_expr.EmptyZero
159 # optional length is None, because it's handled in a special way
160 | Slice(arith_expr begin, arith_expr? length)
161
162 BracedVarSub = (
163 Token left, # in dynamic ParseVarRef, same as name_tok
164 Token name_tok, # location for the name
165 str var_name, # the name - TODO: remove this, use LazyStr() instead
166 Token? prefix_op, # prefix # or ! operators
167 bracket_op? bracket_op,
168 suffix_op? suffix_op,
169 Token right # in dynamic ParseVarRef, same as name_tok
170 )
171
172 # Variants:
173 # - Look at left token ID for $'' c'' vs r'' '' e.g. Id.Left_DollarSingleQuote
174 # - And """ and ''' e.g. Id.Left_TDoubleQuote
175 DoubleQuoted = (Token left, List[word_part] parts, Token right)
176
177 # Consider making str? sval LAZY, like lexer.LazyStr(tok)
178 SingleQuoted = (Token left, str sval, Token right)
179
180 # e.g. Id.VSub_QMark, Id.VSub_DollarName $foo with lexer.LazyStr()
181 SimpleVarSub = (Token tok)
182
183 CommandSub = (Token left_token, command child, Token right)
184
185 # - can contain word.BracedTree
186 # - no 'Token right' for now, doesn't appear to be used
187 ShArrayLiteral = (Token left, List[word] words, Token right)
188
189 # Unevaluated, typed arguments for func and proc.
190 # Note that ...arg is expr.Spread.
191 ArgList = (
192 Token left, List[expr] pos_args,
193 Token? semi_tok, List[NamedArg] named_args,
194 Token? semi_tok2, expr? block_expr,
195 Token right
196 )
197
198 AssocPair = (CompoundWord key, CompoundWord value)
199
200 word_part =
201 ShArrayLiteral %ShArrayLiteral
202 | BashAssocLiteral(Token left, List[AssocPair] pairs, Token right)
203 | Literal %Token
204 # escaped case is separate so the evaluator doesn't have to check token ID
205 | EscapedLiteral(Token token, str ch)
206 | SingleQuoted %SingleQuoted
207 | DoubleQuoted %DoubleQuoted
208 # Could be SimpleVarSub %Token that's VSub_DollarName, but let's not
209 # confuse with the comon word_part.Literal is common for wno
210 | SimpleVarSub %SimpleVarSub
211 | BracedVarSub %BracedVarSub
212 | ZshVarSub (Token left, CompoundWord ignored, Token right)
213 # For command sub and process sub: $(...) <(...) >(...)
214 | CommandSub %CommandSub
215 # ~ or ~bob
216 | TildeSub(Token left, # always the tilde
217 Token? name, str? user_name)
218 | ArithSub(Token left, arith_expr anode, Token right)
219 # {a,b,c}
220 | BracedTuple(List[CompoundWord] words)
221 # {1..10} or {-5..10..2} or {01..10} (leading zeros matter)
222 # {a..f} or {a..f..2} or {a..f..-2}
223 # the whole range is one Token,
224 | BracedRange(Token blame_tok, id kind, str start, str end, int step)
225 # extended globs are parsed statically, unlike globs
226 | ExtGlob(Token op, List[CompoundWord] arms, Token right)
227 # a regex group is similar to an extended glob part
228 | BashRegexGroup(Token left, CompoundWord? child, Token right)
229
230 # YSH word_part extensions
231
232 # @myarray - Id.Lit_Splice (could be optimized to %Token)
233 | Splice(Token blame_tok, str var_name)
234 # $[d.key], etc.
235 | ExprSub(Token left, expr child, Token right)
236
237 # Use cases for Empty: RHS of 'x=', the argument in "${x:-}".
238 # The latter is semantically necessary. (See osh/word_parse.py).
239 # At runtime: RHS of 'declare x='.
240 rhs_word = Empty | Compound %CompoundWord
241
242 word =
243 # Returns from WordParser, but not generally stored in LST
244 Operator %Token
245 # A Compound word can contain any word_part except the Braced*Part.
246 # We could model this with another variant type but it incurs runtime
247 # overhead and seems like overkill. Note that DoubleQuoted can't
248 # contain a SingleQuoted, etc. either.
249 | Compound %CompoundWord
250 # For word sequences command.Simple, ShArrayLiteral, for_iter.Words
251 # Could be its own type
252 | BracedTree(List[word_part] parts)
253 # For dynamic parsing of test aka [ - the string is already evaluated.
254 | String(id id, str s, CompoundWord? blame_loc)
255
256 # Note: the name 'foo' is derived from token value 'foo=' or 'foo+='
257 sh_lhs =
258 Name(Token left, str name) # Lit_VarLike foo=
259 # TODO: Could be Name %Token
260 | IndexedName(Token left, str name, arith_expr index)
261 | UnparsedIndex(Token left, str name, str index) # for translation
262
263 arith_expr =
264 EmptyZero # these are valid: $(( )) (( )) ${a[@]: : }
265 | EmptyOne # condition is 1 for infinite loop: for (( ; ; ))
266 | VarSub %Token # e.g. $(( x )) Id.Arith_VarLike
267 | Word %CompoundWord # e.g. $(( 123'456'$y ))
268
269 | UnaryAssign(id op_id, arith_expr child)
270 | BinaryAssign(id op_id, arith_expr left, arith_expr right)
271
272 | Unary(id op_id, arith_expr child)
273 | Binary(Token op, arith_expr left, arith_expr right)
274 | TernaryOp(arith_expr cond, arith_expr true_expr, arith_expr false_expr)
275
276 bool_expr =
277 WordTest(word w) # e.g. [[ myword ]]
278 | Binary(id op_id, word left, word right)
279 | Unary(id op_id, word child)
280 | LogicalNot(bool_expr child)
281 | LogicalAnd(bool_expr left, bool_expr right)
282 | LogicalOr(bool_expr left, bool_expr right)
283
284 redir_loc =
285 Fd(int fd) | VarName(str name)
286
287 redir_param =
288 Word %CompoundWord
289 | HereWord(CompoundWord w, bool is_multiline)
290 | HereDoc(word here_begin, # e.g. EOF or 'EOF'
291 Token? here_end_tok, # Token consisting of the whole line
292 # It's always filled in AFTER creation, but
293 # temporarily so optional
294 List[word_part] stdin_parts # one for each line
295 )
296
297 Redir = (Token op, redir_loc loc, redir_param arg)
298
299 assign_op = Equal | PlusEqual
300 AssignPair = (Token left, sh_lhs lhs, assign_op op, rhs_word rhs)
301 # TODO: could put Id.Lit_VarLike foo= into LazyStr() with -1 slice
302 EnvPair = (Token left, str name, rhs_word val)
303
304 List_of_command < List[command]
305
306 condition =
307 Shell %List_of_command # if false; true; then echo hi; fi
308 | YshExpr(expr e) # if (x > 0) { echo hi }
309 # TODO: add more specific blame location
310
311 # Each arm tests one word against multiple words
312 # shell: *.cc|*.h) echo C++ ;;
313 # YSH: *.cc|*.h { echo C++ }
314 #
315 # Three location tokens:
316 # 1. left - shell has ( or *.cc ysh has *.cc
317 # 2. middle - shell has ) ysh has {
318 # 3. right - shell has optional ;; ysh has required }
319 #
320 # For YSH typed case, left can be ( and /
321 # And case_pat may contain more details
322 CaseArm = (
323 Token left, pat pattern, Token middle, List[command] action,
324 Token? right
325 )
326
327 # The argument to match against in a case command
328 # In YSH-style case commands we match against an `expr`, but in sh-style case
329 # commands we match against a word.
330 case_arg =
331 Word(word w)
332 | YshExpr(expr e)
333
334 EggexFlag = (bool negated, Token flag)
335
336 # canonical_flags can be compared for equality. This is needed to splice
337 # eggexes correctly, e.g. / 'abc' @pat ; i /
338 Eggex = (
339 Token left, re regex, List[EggexFlag] flags, Token? trans_pref,
340 str? canonical_flags)
341
342 pat =
343 Else
344 | Words(List[word] words)
345 | YshExprs(List[expr] exprs)
346 | Eggex %Eggex
347
348 # Each if arm starts with either an "if" or "elif" keyword
349 # In YSH, the then keyword is not used (replaced by braces {})
350 IfArm = (
351 Token keyword, condition cond, Token? then_kw, List[command] action,
352 # then_tok used in ysh-ify
353 Token? then_tok)
354
355 for_iter =
356 Args # for x; do echo $x; done # implicit "$@"
357 | Words(List[word] words) # for x in 'foo' *.py { echo $x }
358 # like ShArrayLiteral, but no location for %(
359 | YshExpr(expr e, Token blame) # for x in (mylist) { echo $x }
360 #| Files(Token left, List[word] words)
361 # for x in <> {
362 # for x in < @myfiles > {
363
364 BraceGroup = (
365 Token left, Token? doc_token, List[command] children, Token right
366 )
367
368 Param = (Token blame_tok, str name, TypeExpr? type, expr? default_val)
369 RestParam = (Token blame_tok, str name)
370
371 ParamGroup = (List[Param] params, RestParam? rest_of)
372
373 # 'open' is for proc p { }; closed is for proc p () { }
374 proc_sig =
375 Open
376 | Closed(ParamGroup? word, ParamGroup? positional, ParamGroup? named,
377 Param? block_param)
378
379 Proc = (Token keyword, Token name, proc_sig sig, command body)
380
381 Func = (
382 Token keyword, Token name,
383 ParamGroup? positional, ParamGroup? named,
384 command body
385 )
386
387 # Represents all these case: s=1 s+=1 s[x]=1 ...
388 ParsedAssignment = (Token? left, Token? close, int part_offset, CompoundWord w)
389
390 command =
391 NoOp
392
393 # can wrap many children, e.g. { }, loops, functions
394 | Redirect(command child, List[Redir] redirects)
395
396 | Simple(Token? blame_tok, # TODO: make required (BracedTuple?)
397 List[EnvPair] more_env,
398 List[word] words,
399 ArgList? typed_args, LiteralBlock? block,
400 # is_last_cmd is used for fork() optimizations
401 bool is_last_cmd)
402
403 # This doesn't technically belong in the LST, but it's convenient for
404 # execution
405 | ExpandedAlias(command child, List[EnvPair] more_env)
406 | Sentence(command child, Token terminator)
407 # Represents "bare assignment"
408 # Token left is redundant with pairs[0].left
409 | ShAssignment(Token left, List[AssignPair] pairs)
410
411 | ControlFlow(Token keyword, word? arg_word)
412
413 # ops are | |&
414 | Pipeline(Token? negated, List[command] children, List[Token] ops)
415 # ops are && ||
416 | AndOr(List[command] children, List[Token] ops)
417
418 # Part of for, while, until (but not if, case, ShFunction). No redirects.
419 | DoGroup(Token left, List[command] children, Token right)
420 # A brace group is a compound command, with redirects.
421 | BraceGroup %BraceGroup
422 # Contains a single child, like CommandSub
423 | Subshell(Token left, command child, Token right, bool is_last_cmd)
424 | DParen(Token left, arith_expr child, Token right)
425 | DBracket(Token left, bool_expr expr, Token right)
426
427 # up to 3 iterations variables
428 | ForEach(Token keyword, List[str] iter_names, for_iter iterable,
429 Token? semi_tok, command body)
430 # C-style for loop. Any of the 3 expressions can be omitted.
431 # Note: body is required, but only optional here because of initialization
432 # order.
433 | ForExpr(Token keyword, arith_expr? init, arith_expr? cond,
434 arith_expr? update, command? body)
435 | WhileUntil(Token keyword, condition cond, command body)
436
437 | If(Token if_kw, List[IfArm] arms, Token? else_kw, List[command] else_action,
438 Token? fi_kw)
439 | Case(Token case_kw, case_arg to_match, Token arms_start, List[CaseArm] arms,
440 Token arms_end)
441
442 # The keyword is optional in the case of bash-style functions
443 # (ie. "foo() { ... }") which do not have one.
444 | ShFunction(Token? keyword, Token name_tok, str name, command body)
445
446 | TimeBlock(Token keyword, command pipeline)
447 # Some nodes optimize it out as List[command], but we use CommandList for
448 # 1. the top level
449 # 2. ls ; ls & ls (same line)
450 # 3. CommandSub # single child that's a CommandList
451 # 4. Subshell # single child that's a CommandList
452
453 # TODO: Use List_of_command
454 | CommandList(List[command] children)
455
456 # YSH command constructs
457
458 # var, const.
459 # - Keyword is None for hay blocks
460 # - RHS is None, for use with value.Place
461 # - TODO: consider using BareDecl
462 | VarDecl(Token? keyword, List[NameType] lhs, expr? rhs)
463
464 # this can behave like 'var', can be desugared
465 | BareDecl(Token lhs, expr rhs)
466
467 # setvar, maybe 'auto' later
468 | Mutation(Token keyword, List[y_lhs] lhs, Token op, expr rhs)
469 # = keyword
470 | Expr(Token keyword, expr e)
471 | Proc %Proc
472 | Func %Func
473 | Retval(Token keyword, expr val)
474
475 #
476 # Glob representation, for converting ${x//} to extended regexes.
477 #
478
479 # Example: *.[ch] is:
480 # GlobOp(<Glob_Star '*'>),
481 # GlobLit(Glob_OtherLiteral, '.'),
482 # CharClass(False, ['ch']) # from Glob_CleanLiterals token
483
484 glob_part =
485 Literal(id id, str s)
486 | Operator(id op_id) # * or ?
487 | CharClass(bool negated, List[str] strs)
488
489 # Char classes are opaque for now. If we ever need them:
490 # - Collating symbols are [. .]
491 # - Equivalence classes are [=
492
493 printf_part =
494 Literal %Token
495 # flags are 0 hyphen space + #
496 # type is 's' for %s, etc.
497 | Percent(List[Token] flags, Token? width, Token? precision, Token type)
498
499 #
500 # YSH Language
501 #
502 # Copied and modified from Python-3.7/Parser/Python.asdl !
503
504 expr_context = Load | Store | Del | AugLoad | AugStore | Param
505
506 # Type expressions: Int List[Int] Dict[Str, Any]
507 # Do we have Func[Int, Int => Int] ? I guess we can parse that into this
508 # system.
509 TypeExpr = (Token tok, str name, List[TypeExpr] params)
510
511 # LHS bindings in var/const, and eggex
512 NameType = (Token left, str name, TypeExpr? typ)
513
514 # TODO: Inline this into GenExp and ListComp? Just use a flag there?
515 Comprehension = (List[NameType] lhs, expr iter, expr? cond)
516
517 # Named arguments supplied to call. Token is null for f(; ...named).
518 NamedArg = (Token? name, expr value)
519
520 # Subscripts are lists of expressions
521 # a[:i, n] (we don't have matrices, but we have data frames)
522 Subscript = (Token left, expr obj, expr index)
523
524 # Attributes are obj.attr, d->key, name::scope,
525 Attribute = (expr obj, Token op, Token attr, str attr_name, expr_context ctx)
526
527 y_lhs =
528 Var %Token # Id.Expr_Name
529 | Subscript %Subscript
530 | Attribute %Attribute
531
532 place_op =
533 # &a[i+1]
534 Subscript(Token op, expr index)
535 # &d.mykey
536 | Attribute(Token op, Token attr)
537
538 expr =
539 Var(Token left, str name) # a variable name to evaluate
540 # Constants are typically Null, Bool, Int, Float
541 # and also Str for key in {key: 42}
542 # But string literals are SingleQuoted or DoubleQuoted
543 # Python uses Num(object n), which doesn't respect our "LST" invariant.
544 | Const(Token c, value val)
545
546 # read(&x) json read (&x[0])
547 | Place(Token blame_tok, str var_name, place_op* ops)
548
549 # :| one 'two' "$three" |
550 | ShArrayLiteral %ShArrayLiteral
551
552 # / d+ ; ignorecase; %python /
553 | Eggex %Eggex
554
555 # $name is not an expr, but $? is, e.g. Id.VSub_QMark
556 | SimpleVarSub %SimpleVarSub
557 | BracedVarSub %BracedVarSub
558 | CommandSub %CommandSub
559 | SingleQuoted %SingleQuoted
560 | DoubleQuoted %DoubleQuoted
561
562 | Literal(expr inner)
563 | Lambda(List[NameType] params, expr body)
564
565 | Unary(Token op, expr child)
566 | Binary(Token op, expr left, expr right)
567 # x < 4 < 3 and (x < 4) < 3
568 | Compare(expr left, List[Token] ops, List[expr] comparators)
569 | FuncCall(expr func, ArgList args)
570
571 # TODO: Need a representation for method call. We don't just want
572 # Attribute() and then Call()
573
574 | IfExp(expr test, expr body, expr orelse)
575 | Tuple(Token left, List[expr] elts, expr_context ctx)
576
577 | List(Token left, List[expr] elts, expr_context ctx)
578 | Dict(Token left, List[expr] keys, List[expr] values)
579 # For the values in {n1, n2}
580 | Implicit
581
582 | ListComp(Token left, expr elt, List[Comprehension] generators)
583 # not implemented
584 | DictComp(Token left, expr key, expr value, List[Comprehension] generators)
585 | GeneratorExp(expr elt, List[Comprehension] generators)
586
587 # Ranges are written 1:2, with first class expression syntax. There is no
588 # step as in Python. Use range(0, 10, step=2) for that.
589 | Range(expr lower, Token op, expr upper)
590
591 # Slices occur within [] only. Unlike ranges, the start/end can be #
592 # implicit. Like ranges, denote a step with slice(0, 10, step=2).
593 # a[3:] a[:i]
594 | Slice(expr? lower, Token op, expr? upper)
595
596 | Subscript %Subscript
597 | Attribute %Attribute
598
599 # Ellipsis is like 'Starred' within Python, which are valid on the LHS in
600 # Python for unpacking, and # within list literals for splicing.
601 # (Starred is NOT used for {k:v, **a}. That used a blank "keys"
602 # attribute.)
603
604 # I think we can use { **pairs } like Python
605 | Spread(Token left, expr child)
606
607 #
608 # Regex Language (Eggex)
609 #
610
611 # e.g. alnum digit
612 PosixClass = (Token? negated, str name)
613 # e.g. d w s
614 PerlClass = (Token? negated, str name)
615
616 # Char Sets and Ranges both use Char Codes
617 # with u_braced == true : \u{ff}
618 # with u_braced == false: \xff \\ 'a' a '0' 0
619 # ERE doesn't make a distinction, but compiling to Python/PCRE can use it
620 CharCode = (Token blame_tok, int i, bool u_braced)
621 CharRange = (CharCode start, CharCode end)
622
623 # Note: .NET has && in character classes, making it a recursive language
624
625 class_literal_term =
626 PosixClass %PosixClass
627 | PerlClass %PerlClass
628 | CharRange %CharRange
629 | CharCode %CharCode
630
631 | SingleQuoted %SingleQuoted
632 # @chars
633 | Splice(Token name, str var_name) # coudl be Splice %Token
634
635 # evaluated version of class_literal_term (could be in runtime.asdl)
636 char_class_term =
637 PosixClass %PosixClass
638 | PerlClass %PerlClass
639
640 | CharRange %CharRange
641 # For [ \x00 \\ ]
642 | CharCode %CharCode
643
644 # NOTE: modifier is unused now, can represent L or P
645 re_repeat =
646 Op %Token # + * ? or Expr_DecInt for x{3}
647 | Range(Token? left, str lower, str upper, Token? right) # dot{1,2}
648 # Haven't implemented the modifier, e.g. x{+ P}
649 # | Num(Token times, id modifier)
650 # | Range(Token? lower, Token? upper, id modifier)
651
652 re =
653 Primitive(Token blame_tok, id id) # . ^ $ dot %start %end
654 | PosixClass %PosixClass
655 | PerlClass %PerlClass
656 # syntax [ $x \n ]
657 | CharClassLiteral(bool negated, List[class_literal_term] terms)
658 # evaluated [ 'abc' \n ]
659 | CharClass(bool negated, List[char_class_term] terms)
660
661 # @D
662 | Splice(Token name, str var_name) # TODO: Splice %Token ?
663
664 | SingleQuoted %SingleQuoted
665
666 # Compound:
667 | Repeat(re child, re_repeat op)
668 | Seq(List[re] children)
669 | Alt(List[re] children)
670
671 | Group(re child)
672 # convert_func is filled in on evaluation
673 # TODO: name and func_name can be expanded to strings
674 | Capture(re child, Token? name, Token? func_name)
675 | Backtracking(bool negated, Token name, re child)
676
677 # \u{ff} is parsed as this, but SingleQuoted also evaluates to it
678 | LiteralChars(Token blame_tok, str s)
679}