Promote v5.36 usage and feature bundles doc

[perl5.git] / regcomp.sym

# regcomp.sym
#
# File has two sections, divided by a line of dashes '-'. 
#
# Lines beginning with # are ignored, except for those that start with #*
# which are included in pod/perldebguts.pod.  # within a line may be part
# of a description.
#
# First section is for regops, second section is for regmatch-states
#
# Note that the order in this file is important.
#
# Format for first section: 
# NAME \s+ TYPE, arg-description [struct regnode suffix] [flags] [longjump] ; DESCRIPTION
#   arg-description is currently unused
#   suffix is appended to 'struct_regnode_' giving which one to use.  If empty,
#       it means plain 'struct regnode'.  If the regnode is a string one, this
#       should instead refer to the base regnode, without the char[1] element
#       of the structure
#   flag <S> means is REGNODE_SIMPLE; flag <V> means is REGNODE_VARIES; <.> is
#       a placeholder
#   longjump is 1 if the (first) argument holds the next offset (instead of the
#       usual 'next_offset' field
#
# run perl regen.pl after editing this file

#                             +- suffix of which struct regnode to use e.g.,
#                             | +- flags  (S or V)               struct regnode_1
#                         un- | | +- longjmp (0, blank, or 1)  blank means 0
# Name        Type       used | | | ; comment
# --------------------------------------------------------------------------
# IFMATCH     BRANCHJ,    off 1 . 1 ; Succeeds if the following matches.
# UNLESSM     BRANCHJ,    off 1 . 1 ; Fails if the following matches.
# SUSPEND     BRANCHJ,    off 1 V 1 ; "Independent" sub-RE.
# IFTHEN      BRANCHJ,    off 1 V 1 ; Switch, should be preceded by switcher.
# GROUPP      GROUPP,     num 1     ; Whether the group matched.
#
# If we were to start running out of regnodes, many of the ones that are
# complements could be combined with their non-complement mates.  For example,
# POSIXU could have the flags field have the bottom bit mean do we complement
# or not, and the type be shifted left 1 bit.  Then all that would be needed to
# extract which to do is a mask for the complement bit, and a right shift for
# the other, an inconsequential increase in instructions.  It might actually be
# clearer and slightly faster given the case statement and assignment are
# removed.  Note that not everything could be collapsed: NPOSIXA, for example,
# would require special handling for performance.


#* Exit points

END         END,        no        ; End of program.
SUCCEED     END,        no        ; Return from a subroutine, basically.

#* Line Start Anchors:
#Note flags field for SBOL indicates if it is a /^/ or a /\A/
SBOL        BOL,        no        ; Match "" at beginning of line: /^/, /\A/
MBOL        BOL,        no        ; Same, assuming multiline: /^/m

#* Line End Anchors:
SEOL        EOL,        no        ; Match "" at end of line: /$/
MEOL        EOL,        no        ; Same, assuming multiline: /$/m
EOS         EOL,        no        ; Match "" at end of string: /\z/

#* Match Start Anchors:
GPOS        GPOS,       no        ; Matches where last m//g left off.

#* Word Boundary Opcodes:
# The regops that have varieties that vary depending on the character set regex
# modifiers have to ordered thusly: /d, /l, /u, /a, /aa.  This is because code
# in regcomp.c uses the enum value of the modifier as an offset from the /d
# version.  The complements must come after the non-complements.
# BOUND, POSIX and their complements are affected, as well as EXACTF.
BOUND       BOUND,      no        ; Like BOUNDA for non-utf8, otherwise like BOUNDU
BOUNDL      BOUND,      no        ; Like BOUND/BOUNDU, but \w and \W are defined by current locale
BOUNDU      BOUND,      no        ; Match "" at any boundary of a given type using /u rules.
BOUNDA      BOUND,      no        ; Match "" at any boundary between \w\W or \W\w, where \w is [_a-zA-Z0-9]
# All NBOUND nodes are required by code in regexec.c to be greater than all BOUND ones
NBOUND      NBOUND,     no        ; Like NBOUNDA for non-utf8, otherwise like BOUNDU
NBOUNDL     NBOUND,     no        ; Like NBOUND/NBOUNDU, but \w and \W are defined by current locale
NBOUNDU     NBOUND,     no        ; Match "" at any non-boundary of a given type using using /u rules.
NBOUNDA     NBOUND,     no        ; Match "" betweeen any \w\w or \W\W, where \w is [_a-zA-Z0-9]

#* [Special] alternatives:
REG_ANY     REG_ANY,    no 0 S    ; Match any one character (except newline).
SANY        REG_ANY,    no 0 S    ; Match any one character.
ANYOF       ANYOF,      sv charclass S    ; Match character in (or not in) this class, single char match only
ANYOFD      ANYOF,      sv charclass S    ; Like ANYOF, but /d is in effect
ANYOFL      ANYOF,      sv charclass S    ; Like ANYOF, but /l is in effect
ANYOFPOSIXL ANYOF,      sv charclass_posixl S    ; Like ANYOFL, but matches [[:posix:]] classes

# Must be sequential
ANYOFH      ANYOFH,     sv 1 S    ; Like ANYOF, but only has "High" matches, none in the bitmap; the flags field contains the lowest matchable UTF-8 start byte
ANYOFHb     ANYOFH,     sv 1 S    ; Like ANYOFH, but all matches share the same UTF-8 start byte, given in the flags field
ANYOFHr     ANYOFH,     sv 1 S    ; Like ANYOFH, but the flags field contains packed bounds for all matchable UTF-8 start bytes.
ANYOFHs     ANYOFH,     sv:str 1 S    ; Like ANYOFHb, but has a string field that gives the leading matchable UTF-8 bytes; flags field is len
ANYOFR      ANYOFR,     packed 1  S  ; Matches any character in the range given by its packed args: upper 12 bits is the max delta from the base lower 20; the flags field contains the lowest matchable UTF-8 start byte
ANYOFRb     ANYOFR,     packed 1  S ; Like ANYOFR, but all matches share the same UTF-8 start byte, given in the flags field
# There is no ANYOFRr because khw doesn't think there are likely to be
# real-world cases where such a large range is used.
#
# And khw doesn't believe an ANYOFRs (which would behave like ANYOFHs) is
# actually worth it.  On two-byte UTF-8, the first byte alone is all we need,
# and ANYOFR already does that.  And we don't consider non-Unicode code points
# or EBCDIC for performance decisions.  If we had it, we would be comparing the
# strings, and if they are equal convert to UV and then test to see if it is in
# the range.  The fast DFA we now use to do the conversion is slower than
# comparing the strings, but not by much, and negligible in 2 or 3 byte
# operations.  (We don't have to compare the final byte as it has to be
# different or else this wouldn't be a range.)  So we might as well displense
# with the comparisons that ANYOFRs would do, and go directly to do the
# conversion .

ANYOFHbbm   ANYOFHbbm   none bbm S ; Like ANYOFHb, but only for 2-byte UTF-8 characters; uses a bitmap to match the continuation byte

ANYOFM      ANYOFM,     byte 1 S  ; Like ANYOF, but matches an invariant byte as determined by the mask and arg
NANYOFM     ANYOFM,     byte 1 S  ; complement of ANYOFM

#* POSIX Character Classes:
# Order of the below is important.  See ordering comment above.
POSIXD      POSIXD,     none 0 S   ; Some [[:class:]] under /d; the FLAGS field gives which one
POSIXL      POSIXD,     none 0 S   ; Some [[:class:]] under /l; the FLAGS field gives which one
POSIXU      POSIXD,     none 0 S   ; Some [[:class:]] under /u; the FLAGS field gives which one
POSIXA      POSIXD,     none 0 S   ; Some [[:class:]] under /a; the FLAGS field gives which one
NPOSIXD     NPOSIXD,    none 0 S   ; complement of POSIXD, [[:^class:]]
NPOSIXL     NPOSIXD,    none 0 S   ; complement of POSIXL, [[:^class:]]
NPOSIXU     NPOSIXD,    none 0 S   ; complement of POSIXU, [[:^class:]]
NPOSIXA     NPOSIXD,    none 0 S   ; complement of POSIXA, [[:^class:]]
# End of order is important

CLUMP       CLUMP,      no 0 V    ; Match any extended grapheme cluster sequence

#* Alternation

#* BRANCH        The set of branches constituting a single choice are
#*               hooked together with their "next" pointers, since
#*               precedence prevents anything being concatenated to
#*               any individual branch.  The "next" pointer of the last
#*               BRANCH in a choice points to the thing following the
#*               whole choice.  This is also where the final "next"
#*               pointer of each individual branch points; each branch
#*               starts with the operand node of a BRANCH node.
#*
BRANCH      BRANCH,     node 0 V  ; Match this alternative, or the next...

#*Literals
# NOTE: the relative ordering of these types is important do not change it
# By convention, folding nodes begin with EXACTF; A digit 8 is in the name if
# and only if it it requires a UTF-8 target string in order to successfully
# match.

EXACT       EXACT,      str       ; Match this string (flags field is the length).

#* In a long string node, the U32 argument is the length, and is
#* immediately followed by the string.
LEXACT      EXACT,  len:str 1; Match this long string (preceded by length; flags unused).
EXACTL      EXACT,      str       ; Like EXACT, but /l is in effect (used so locale-related warnings can be checked for)
EXACTF      EXACT,      str       ; Like EXACT, but match using /id rules; (string not UTF-8, ASCII folded; non-ASCII not)
EXACTFL     EXACT,      str       ; Like EXACT, but match using /il rules; (string not likely to be folded)
EXACTFU     EXACT,      str	  ; Like EXACT, but match using /iu rules; (string folded)

# The reason MICRO and SHARP S aren't folded in non-UTF8 patterns is because
# they would fold to something that requires UTF-8.  SHARP S would normally
# fold to 'ss', but because of /aa, it instead folds to a pair of LATIN SMALL
# LETTER LONG S characters (U+017F)
EXACTFAA    EXACT,      str	  ; Like EXACT, but match using /iaa rules; (string folded except MICRO in non-UTF8 patterns; doesn't contain SHARP S unless UTF-8; folded length <= unfolded)
# must immediately follow EXACTFAA
EXACTFAA_NO_TRIE  EXACT, str	  ; Like EXACTFAA, (string not UTF-8, folded except: MICRO, SHARP S; folded length <= unfolded, not currently trie-able)

# End of important relative ordering.

EXACTFUP    EXACT,      str	  ; Like EXACT, but match using /iu rules; (string not UTF-8, folded except MICRO: hence Problematic)
# In order for a non-UTF-8 EXACTFAA to think the pattern is pre-folded when
# matching a UTF-8 target string, there would have to be something like an
# EXACTFAA_MICRO which would not be considered pre-folded for UTF-8 targets,
# since the fold of the MICRO SIGN would not be done, and would be
# representable in the UTF-8 target string.

EXACTFLU8   EXACT,      str	  ; Like EXACTFU, but use /il, UTF-8, (string is folded, and everything in it is above 255
EXACT_REQ8   EXACT,      str      ; Like EXACT, but only UTF-8 encoded targets can match
LEXACT_REQ8  EXACT,  len:str 1    ; Like LEXACT, but only UTF-8 encoded targets can match
EXACTFU_REQ8 EXACT,    str        ; Like EXACTFU, but only UTF-8 encoded targets can match
# One could add EXACTFAA8 and something that has the same effect for /l,
# but these would be extremely uncommon

EXACTFU_S_EDGE EXACT,   str       ; /di rules, but nothing in it precludes /ui, except begins and/or ends with [Ss]; (string not UTF-8; compile-time only)

#*New charclass like patterns
LNBREAK     LNBREAK,    none      ; generic newline pattern

#*Trie Related

#* Behave the same as A|LIST|OF|WORDS would. The '..C' variants
#* have inline charclass data (ascii only), the 'C' store it in the
#* structure.
# NOTE: the relative order of the TRIE-like regops  is significant

TRIE        TRIE,       trie 1    ; Match many EXACT(F[ALU]?)? at once. flags==type
TRIEC       TRIE,trie charclass   ; Same as TRIE, but with embedded charclass data

# For start classes, contains an added fail table.
AHOCORASICK     TRIE,   trie 1    ; Aho Corasick stclass. flags==type
AHOCORASICKC    TRIE,trie charclass   ; Same as AHOCORASICK, but with embedded charclass data

#*Do nothing types

NOTHING     NOTHING,    no        ; Match empty string.
#*A variant of above which delimits a group, thus stops optimizations
TAIL        NOTHING,    no        ; Match empty string. Can jump here from outside.

#*Loops

#* STAR,PLUS    '?', and complex '*' and '+', are implemented as
#*               circular BRANCH structures.  Simple cases
#*               (one character per match) are implemented with STAR
#*               and PLUS for speed and to minimize recursive plunges.
#*
STAR        STAR,       node 0 V  ; Match this (simple) thing 0 or more times: /A{0,}B/ where A is width 1 char
PLUS        PLUS,       node 0 V  ; Match this (simple) thing 1 or more times: /A{1,}B/ where A is width 1 char

CURLY       CURLY,      sv 2 V    ; Match this (simple) thing {n,m} times: /A{m,n}B/ where A is width 1 char
CURLYN      CURLY,      no 2 V    ; Capture next-after-this simple thing: /(A){m,n}B/ where A is width 1 char
CURLYM      CURLY,      no 2 V    ; Capture this medium-complex thing {n,m} times: /(A){m,n}B/ where A is fixed-length
CURLYX      CURLY,      sv 2 V    ; Match/Capture this complex thing {n,m} times.

#*This terminator creates a loop structure for CURLYX
WHILEM      WHILEM,     no 0 V    ; Do curly processing and see if rest matches.

#*Buffer related

#*OPEN,CLOSE,GROUPP     ...are numbered at compile time.
OPEN        OPEN,       num 1     ; Mark this point in input as start of #n.
CLOSE       CLOSE,      num 1     ; Close corresponding OPEN of #n.
SROPEN      SROPEN,     none      ; Same as OPEN, but for script run
SRCLOSE     SRCLOSE,    none      ; Close preceding SROPEN

REF         REF,        num 1 V   ; Match some already matched string
REFF        REF,        num 1 V   ; Match already matched string, using /di rules.
REFFL       REF,        num 1 V   ; Match already matched string, using /li rules.
# N?REFF[AU] could have been implemented using the FLAGS field of the
# regnode, but by having a separate node type, we can use the existing switch
# statement to avoid some tests
REFFU       REF,        num 1 V   ; Match already matched string, usng /ui.
REFFA       REF,        num 1 V   ; Match already matched string, using /aai rules.

#*Named references.  Code in regcomp.c assumes that these all are after
#*the numbered references
REFN        REF,        no-sv 1 V ; Match some already matched string
REFFN       REF,        no-sv 1 V ; Match already matched string, using /di rules.
REFFLN      REF,        no-sv 1 V ; Match already matched string, using /li rules.
REFFUN      REF,        num   1 V ; Match already matched string, using /ui rules.
REFFAN      REF,        num   1 V ; Match already matched string, using /aai rules.

#*Support for long RE
LONGJMP     LONGJMP,    off 1 . 1 ; Jump far away.
BRANCHJ     BRANCHJ,    off 1 V 1 ; BRANCH with long offset.

#*Special Case Regops
IFMATCH     BRANCHJ,    off 1 . 1 ; Succeeds if the following matches; non-zero flags "f", next_off "o" means lookbehind assertion starting "f..(f-o)" characters before current
UNLESSM     BRANCHJ,    off 1 . 1 ; Fails if the following matches; non-zero flags "f", next_off "o" means lookbehind assertion starting "f..(f-o)" characters before current
SUSPEND     BRANCHJ,    off 1 V 1 ; "Independent" sub-RE.
IFTHEN      BRANCHJ,    off 1 V 1 ; Switch, should be preceded by switcher.
GROUPP      GROUPP,     num 1     ; Whether the group matched.

#*The heavy worker

EVAL        EVAL,       evl/flags 2L ; Execute some Perl code.

#*Modifiers

MINMOD      MINMOD,     no        ; Next operator is not greedy.
LOGICAL     LOGICAL,    no        ; Next opcode should set the flag only.

#*This is not used yet
RENUM       BRANCHJ,    off 1 . 1 ; Group with independently numbered parens.

#*Regex Subroutines
GOSUB       GOSUB,      num/ofs 2L    ; recurse to paren arg1 at (signed) ofs arg2

#*Special conditionals
GROUPPN     GROUPPN,    no-sv 1   ; Whether the group matched.
INSUBP      INSUBP,     num 1     ; Whether we are in a specific recurse.  
DEFINEP     DEFINEP,    none 1    ; Never execute directly.               

#*Backtracking Verbs
ENDLIKE     ENDLIKE,    none      ; Used only for the type field of verbs
OPFAIL      ENDLIKE,    no-sv 1   ; Same as (?!), but with verb arg
ACCEPT      ENDLIKE,    no-sv/num 2L   ; Accepts the current matched string, with verbar

#*Verbs With Arguments
VERB        VERB,       no-sv 1   ; Used only for the type field of verbs
PRUNE       VERB,       no-sv 1   ; Pattern fails at this startpoint if no-backtracking through this 
MARKPOINT   VERB,       no-sv 1   ; Push the current location for rollback by cut.
SKIP        VERB,       no-sv 1   ; On failure skip forward (to the mark) before retrying
COMMIT      VERB,       no-sv 1   ; Pattern fails outright if backtracking through this
CUTGROUP    VERB,       no-sv 1   ; On failure go to the next alternation in the group

#*Control what to keep in $&.
KEEPS       KEEPS,      no        ; $& begins here.

#*Validate that lookbehind IFMATCH and UNLESSM end at the right place
LOOKBEHIND_END   END,        no        ; Return from lookbehind (IFMATCH/UNLESSM) and validate position

# NEW STUFF SOMEWHERE ABOVE THIS LINE.  Stuff that regexec.c: find_byclass()
# and regrepeat() use should go way above, near LNBREAK to allow a more compact
# jump table to be generated for their switch() statements

################################################################################

#*SPECIAL  REGOPS

#* This is not really a node, but an optimized away piece of a "long"
#* node.  To simplify debugging output, we mark it as if it were a node
OPTIMIZED   NOTHING,    off       ; Placeholder for dump.

#* Special opcode with the property that no opcode in a compiled program
#* will ever be of this type. Thus it can be used as a flag value that
#* no other opcode has been seen. END is used similarly, in that an END
#* node cant be optimized. So END implies "unoptimizable" and PSEUDO
#* mean "not seen anything to optimize yet".
PSEUDO      PSEUDO,     off       ; Pseudo opcode for internal use.

REGEX_SET   REGEX_SET,  depth p S ; Regex set, temporary node used in pre-optimization compilation

-------------------------------------------------------------------------------
# Format for second section:
# REGOP \t typelist [ \t typelist]
# typelist= namelist
#         = namelist:FAIL
#         = name:count

# Anything below is a state
#
#
TRIE            next:FAIL
EVAL            B,postponed_AB:FAIL
CURLYX          end:FAIL
WHILEM          A_pre,A_min,A_max,B_min,B_max:FAIL
BRANCH          next:FAIL
CURLYM          A,B:FAIL
IFMATCH         A:FAIL
CURLY           B_min,B_max:FAIL
COMMIT          next:FAIL
MARKPOINT       next:FAIL
SKIP            next:FAIL
CUTGROUP        next:FAIL
KEEPS           next:FAIL