# Copyright (C) 2016 and later: Unicode, Inc. and others.
# License & terms of use: http://www.unicode.org/copyright.html
#*****************************************************************************
#
#   Copyright (C) 2002-2015, International Business Machines Corporation and others.
#   All Rights Reserved.
#
#*****************************************************************************
#
#  file:  regexcst.txt
#  ICU Regular Expression Parser State Table
#
#     This state table is used when reading and parsing a regular expression pattern
#     The pattern parser uses a state machine; the data in this file define the
#     state transitions that occur for each input character.
#
#     *** This file defines the regex pattern grammar.   This is it.
#     *** The determination of what is accepted is here.
#
#     This file is processed by a perl script "regexcst.pl" to produce initialized C arrays
#     that are then built with the rule parser.
#

#
# Here is the syntax of the state definitions in this file:
#
#
#StateName:
#   input-char           n next-state           ^push-state     action
#   input-char           n next-state           ^push-state     action
#       |                |   |                      |             |
#       |                |   |                      |             |--- action to be performed by state machine
#       |                |   |                      |                  See function RBBIRuleScanner::doParseActions()
#       |                |   |                      |
#       |                |   |                      |--- Push this named state onto the state stack.
#       |                |   |                           Later, when next state is specified as "pop",
#       |                |   |                           the pushed state will become the current state.
#       |                |   |
#       |                |   |--- Transition to this state if the current input character matches the input
#       |                |        character or char class in the left hand column.  "pop" causes the next
#       |                |        state to be popped from the state stack.
#       |                |
#       |                |--- When making the state transition specified on this line, advance to the next
#       |                     character from the input only if 'n' appears here.
#       |
#       |--- Character or named character classes to test for.  If the current character being scanned
#            matches, peform the actions and go to the state specified on this line.
#            The input character is tested sequentally, in the order written.  The characters and
#            character classes tested for do not need to be mutually exclusive.  The first match wins.
#




#
#  start state, scan position is at the beginning of the pattern.
#
start:
   default                 term                                     doPatStart




#
#  term.  At a position where we can accept the start most items in a pattern.
#
term:
    quoted               n expr-quant                               doLiteralChar
    rule_char            n expr-quant                               doLiteralChar
    '['                  n set-open       ^set-finish               doSetBegin
    '('                  n open-paren
    '.'                  n expr-quant                               doDotAny
    '^'                  n expr-quant                               doCaret
    '$'                  n expr-quant                               doDollar
    '\'                  n backslash
    '|'                  n  term                                    doOrOperator
    ')'                  n  pop                                     doCloseParen
    eof                       term                                     doPatFinish
    default                errorDeath                               doRuleError



#
#   expr-quant    We've just finished scanning a term, now look for the optional
#                 trailing quantifier - *, +, ?, *?,  etc.
#
expr-quant:
    '*'                  n  quant-star
    '+'                  n  quant-plus
    '?'                  n  quant-opt
    '{'                  n  interval-open                          doIntervalInit
    '('                  n  open-paren-quant
    default                 expr-cont


#
#  expr-cont      Expression, continuation.  At a point where additional terms are
#                                            allowed, but not required.  No Quantifiers
#
expr-cont:
    '|'                  n  term                                    doOrOperator
    ')'                  n  pop                                     doCloseParen
    default                 term


#
#   open-paren-quant   Special case handling for comments appearing before a quantifier,
#                        e.g.   x(?#comment )*
#                      Open parens from expr-quant come here; anything but a (?# comment
#                      branches into the normal parenthesis sequence as quickly as possible.
#
open-paren-quant:
    '?'                  n  open-paren-quant2                      doSuppressComments
    default                 open-paren

open-paren-quant2:
    '#'                  n  paren-comment   ^expr-quant
    default                 open-paren-extended


#
#   open-paren    We've got an open paren.  We need to scan further to
#                 determine what kind of quantifier it is - plain (, (?:, (?>, or whatever.
#
open-paren:
    '?'                  n  open-paren-extended                     doSuppressComments
    default                 term            ^expr-quant             doOpenCaptureParen

open-paren-extended:
    ':'                  n  term            ^expr-quant             doOpenNonCaptureParen  #  (?:
    '>'                  n  term            ^expr-quant             doOpenAtomicParen      #  (?>
    '='                  n  term            ^expr-cont              doOpenLookAhead        #  (?=
    '!'                  n  term            ^expr-cont              doOpenLookAheadNeg     #  (?!
    '<'                  n  open-paren-lookbehind
    '#'                  n  paren-comment   ^term
    'i'                     paren-flag                              doBeginMatchMode
    'd'                     paren-flag                              doBeginMatchMode
    'm'                     paren-flag                              doBeginMatchMode
    's'                     paren-flag                              doBeginMatchMode
    'u'                     paren-flag                              doBeginMatchMode
    'w'                     paren-flag                              doBeginMatchMode
    'x'                     paren-flag                              doBeginMatchMode
    '-'                     paren-flag                              doBeginMatchMode
    '('                  n  errorDeath                              doConditionalExpr
    '{'                  n  errorDeath                              doPerlInline
    default                 errorDeath                              doBadOpenParenType

open-paren-lookbehind:
    '='                  n  term            ^expr-cont              doOpenLookBehind       #  (?<=
    '!'                  n  term            ^expr-cont              doOpenLookBehindNeg    #  (?<!
    ascii_letter            named-capture                           doBeginNamedCapture    #  (?<name
    default                 errorDeath                              doBadOpenParenType


#
#   paren-comment    We've got a (?# ... )  style comment.  Eat pattern text till we get to the ')'
#
paren-comment:
    ')'                  n  pop
    eof                        errorDeath                              doMismatchedParenErr
    default              n  paren-comment

#
#  paren-flag    Scanned a (?ismx-ismx  flag setting
#
paren-flag:
    'i'                  n  paren-flag                              doMatchMode
    'd'                  n  paren-flag                              doMatchMode
    'm'                  n  paren-flag                              doMatchMode
    's'                  n  paren-flag                              doMatchMode
    'u'                  n  paren-flag                              doMatchMode
    'w'                  n  paren-flag                              doMatchMode
    'x'                  n  paren-flag                              doMatchMode
    '-'                  n  paren-flag                              doMatchMode
    ')'                  n  term                                    doSetMatchMode
    ':'                  n  term              ^expr-quant           doMatchModeParen
    default                 errorDeath                              doBadModeFlag

#
#  named-capture    (?<name> ... ), position currently on the name.
#
named-capture:
    ascii_letter         n  named-capture                           doContinueNamedCapture
    digit_char           n  named-capture                           doContinueNamedCapture
    '>'                  n  term               ^expr-quant          doOpenCaptureParen      # common w non-named capture.
    default                 errorDeath                              doBadNamedCapture

#
#  quant-star     Scanning a '*' quantifier.  Need to look ahead to decide
#                 between plain '*', '*?', '*+'
#
quant-star:
     '?'                 n  expr-cont                               doNGStar               #  *?
     '+'                 n  expr-cont                               doPossessiveStar       #  *+
     default                expr-cont                               doStar


#
#  quant-plus     Scanning a '+' quantifier.  Need to look ahead to decide
#                 between plain '+', '+?', '++'
#
quant-plus:
     '?'                 n  expr-cont                               doNGPlus               #  *?
     '+'                 n  expr-cont                               doPossessivePlus       #  *+
     default                expr-cont                               doPlus


#
#  quant-opt  Scanning a '?' quantifier.  Need to look ahead to decide
#                  between plain '?', '??', '?+'
#
quant-opt:
     '?'                 n  expr-cont                               doNGOpt                 #  ??
     '+'                 n  expr-cont                               doPossessiveOpt         #  ?+
     default                expr-cont                               doOpt                   #  ?


#
#   Interval         scanning a '{', the opening delimiter for an interval specification
#                                   {number} or {min, max} or {min,}
#
interval-open:
    digit_char              interval-lower
    default                 errorDeath                              doIntervalError

interval-lower:
    digit_char           n  interval-lower                          doIntevalLowerDigit
    ','                     n  interval-upper
    '}'                  n  interval-type                           doIntervalSame             # {n}
    default                 errorDeath                              doIntervalError

interval-upper:
    digit_char           n  interval-upper                          doIntervalUpperDigit
    '}'                  n  interval-type
    default                 errorDeath                              doIntervalError

interval-type:
    '?'                  n  expr-cont                               doNGInterval                # {n,m}?
    '+'                  n  expr-cont                               doPossessiveInterval        # {n,m}+
    default                 expr-cont                               doInterval                  # {m,n}


#
#  backslash        #  Backslash.  Figure out which of the \thingies we have encountered.
#                                  The low level next-char function will have preprocessed
#                                  some of them already; those won't come here.
backslash:
   'A'                   n  term                                    doBackslashA
   'B'                   n  term                                    doBackslashB
   'b'                   n  term                                    doBackslashb
   'd'                   n  expr-quant                              doBackslashd
   'D'                   n  expr-quant                              doBackslashD
   'G'                   n  term                                    doBackslashG
   'h'                   n  expr-quant                              doBackslashh
   'H'                   n  expr-quant                              doBackslashH
   'k'                   n  named-backref
   'N'                      expr-quant                              doNamedChar      #   \N{NAME}  named char
   'p'                      expr-quant                              doProperty       #   \p{Lu}  style property
   'P'                      expr-quant                              doProperty
   'R'                   n  expr-quant                              doBackslashR
   'Q'                   n  term                                    doEnterQuoteMode
   'S'                   n  expr-quant                              doBackslashS
   's'                   n  expr-quant                              doBackslashs
   'v'                   n  expr-quant                              doBackslashv
   'V'                   n  expr-quant                              doBackslashV
   'W'                   n  expr-quant                              doBackslashW
   'w'                   n  expr-quant                              doBackslashw
   'X'                   n  expr-quant                              doBackslashX
   'Z'                   n  term                                    doBackslashZ
   'z'                   n  term                                    doBackslashz
   digit_char            n  expr-quant                              doBackRef         #  Will scan multiple digits
   eof                      errorDeath                              doEscapeError
   default               n  expr-quant                              doEscapedLiteralChar


# named-backref   Scanned \k
#                 Leading to \k<captureName>
#                 Failure to get the full sequence is an error.
#
named-backref:
    '<'                  n  named-backref-2                         doBeginNamedBackRef
    default                 errorDeath                              doBadNamedCapture

named-backref-2:
    ascii_letter         n  named-backref-3                         doContinueNamedBackRef
    default                 errorDeath                              doBadNamedCapture

named-backref-3:
    ascii_letter         n  named-backref-3                         doContinueNamedBackRef
    digit_char           n  named-backref-3                         doContinueNamedBackRef
    '>'                  n  expr-quant                              doCompleteNamedBackRef
    default                 errorDeath                              doBadNamedCapture


#
# [set expression] parsing,
#    All states involved in parsing set expressions have names beginning with "set-"
#

set-open:
   '^'                   n  set-open2                               doSetNegate
   ':'                      set-posix                               doSetPosixProp
   default                  set-open2

set-open2:
   ']'                   n  set-after-lit                           doSetLiteral
   default                  set-start

#  set-posix:
#                  scanned a '[:'  If it really is a [:property:], doSetPosixProp will have
#                  moved the scan to the closing ']'.  If it wasn't a property
#                  expression, the scan will still be at the opening ':', which should
#                  be interpreted as a normal set expression.
set-posix:
    ']'                  n   pop                                    doSetEnd
    ':'                      set-start
    default                  errorDeath                             doRuleError  # should not be possible.

#
#   set-start   after the [ and special case leading characters (^ and/or ]) but before
#               everything else.   A '-' is literal at this point.
#
set-start:
    ']'                  n  pop                                     doSetEnd
    '['                  n  set-open      ^set-after-set            doSetBeginUnion
    '\'                  n  set-escape
    '-'                  n  set-start-dash
    '&'                  n  set-start-amp
    default              n  set-after-lit                           doSetLiteral

#    set-start-dash    Turn "[--" into a syntax error.
#                           "[-x" is good, - and x are literals.
#
set-start-dash:
    '-'                     errorDeath                              doRuleError
    default                 set-after-lit                           doSetAddDash

#    set-start-amp     Turn "[&&" into a syntax error.
#                           "[&x" is good, & and x are literals.
#
set-start-amp:
    '&'                     errorDeath                              doRuleError
    default                 set-after-lit                           doSetAddAmp

#
#   set-after-lit    The last thing scanned was a literal character within a set.
#                    Can be followed by anything.  Single '-' or '&' are
#                    literals in this context, not operators.
set-after-lit:
    ']'                  n  pop                                     doSetEnd
    '['                  n  set-open      ^set-after-set            doSetBeginUnion
    '-'                  n  set-lit-dash
    '&'                  n  set-lit-amp
    '\'                  n  set-escape
    eof                     errorDeath                              doSetNoCloseError
    default              n  set-after-lit                           doSetLiteral

set-after-set:
    ']'                  n  pop                                     doSetEnd
    '['                  n  set-open      ^set-after-set            doSetBeginUnion
    '-'                  n  set-set-dash
    '&'                  n  set-set-amp
    '\'                  n  set-escape
    eof                     errorDeath                              doSetNoCloseError
    default              n  set-after-lit                           doSetLiteral

set-after-range:
    ']'                  n  pop                                     doSetEnd
    '['                  n  set-open      ^set-after-set            doSetBeginUnion
    '-'                  n  set-range-dash
    '&'                  n  set-range-amp
    '\'                  n  set-escape
    eof                     errorDeath                              doSetNoCloseError
    default              n  set-after-lit                           doSetLiteral


# set-after-op
#     After a --  or &&
#     It is an error to close a set at this point.
#
set-after-op:
    '['                  n  set-open         ^set-after-set         doSetBeginUnion
    ']'                     errorDeath                              doSetOpError
    '\'                  n  set-escape
    default              n  set-after-lit                           doSetLiteral

#
#   set-set-amp
#      Have scanned [[set]&
#      Could be a '&' intersection operator, if a set follows.
#      Could be the start of a '&&' operator.
#      Otherewise is a literal.
set-set-amp:
    '['                  n  set-open      ^set-after-set           doSetBeginIntersection1
    '&'                  n  set-after-op                           doSetIntersection2
    default                 set-after-lit                          doSetAddAmp


# set-lit-amp   Have scanned "[literals&"
#               Could be a start of "&&" operator or a literal
#               In [abc&[def]],   the '&' is a literal
#
set-lit-amp:
    '&'                  n  set-after-op                            doSetIntersection2
    default                 set-after-lit                           doSetAddAmp


#
#  set-set-dash
#      Have scanned [set]-
#      Could be a '-' difference operator, if a [set] follows.
#      Could be the start of a '--' operator.
#      Otherewise is a literal.
set-set-dash:
    '['                  n  set-open      ^set-after-set           doSetBeginDifference1
    '-'                  n  set-after-op                           doSetDifference2
    default                 set-after-lit                          doSetAddDash


#
#  set-range-dash
#      scanned  a-b-  or \w-
#         any set or range like item where the trailing single '-' should
#         be literal, not a set difference operation.
#         A trailing "--" is still a difference operator.
set-range-dash:
    '-'                  n  set-after-op                           doSetDifference2
    default                 set-after-lit                          doSetAddDash


set-range-amp:
    '&'                  n  set-after-op                           doSetIntersection2
    default                 set-after-lit                          doSetAddAmp


#  set-lit-dash
#     Have scanned "[literals-" Could be a range or a -- operator or a literal
#     In [abc-[def]], the '-' is a literal (confirmed with a Java test)
#        [abc-\p{xx}  the '-' is an error
#        [abc-]       the '-' is a literal
#        [ab-xy]      the '-' is a range
#
set-lit-dash:
    '-'                  n  set-after-op                            doSetDifference2
    '['                     set-after-lit                           doSetAddDash
    ']'                     set-after-lit                           doSetAddDash
    '\'                  n  set-lit-dash-escape
    default              n  set-after-range                         doSetRange

# set-lit-dash-escape
#
#    scanned "[literal-\"
#    Could be a range, if the \ introduces an escaped literal char or a named char.
#    Otherwise it is an error.
#
set-lit-dash-escape:
   's'                      errorDeath                             doSetOpError
   'S'                      errorDeath                             doSetOpError
   'w'                      errorDeath                             doSetOpError
   'W'                      errorDeath                             doSetOpError
   'd'                      errorDeath                             doSetOpError
   'D'                      errorDeath                             doSetOpError
   'N'                      set-after-range                        doSetNamedRange
   default               n  set-after-range                        doSetRange


#
#  set-escape
#       Common back-slash escape processing within set expressions
#
set-escape:
   'p'                      set-after-set                           doSetProp
   'P'                      set-after-set                           doSetProp
   'N'                      set-after-lit                           doSetNamedChar
   's'                   n  set-after-range                         doSetBackslash_s
   'S'                   n  set-after-range                         doSetBackslash_S
   'w'                   n  set-after-range                         doSetBackslash_w
   'W'                   n  set-after-range                         doSetBackslash_W
   'd'                   n  set-after-range                         doSetBackslash_d
   'D'                   n  set-after-range                         doSetBackslash_D
   'h'                   n  set-after-range                         doSetBackslash_h
   'H'                   n  set-after-range                         doSetBackslash_H
   'v'                   n  set-after-range                         doSetBackslash_v
   'V'                   n  set-after-range                         doSetBackslash_V
   default               n  set-after-lit                           doSetLiteralEscaped

#
# set-finish
#     Have just encountered the final ']' that completes a [set], and
#     arrived here via a pop.  From here, we exit the set parsing world, and go
#     back to generic regular expression parsing.
#
set-finish:
    default                 expr-quant                              doSetFinish


#
# errorDeath.   This state is specified as the next state whenever a syntax error
#               in the source rules is detected.  Barring bugs, the state machine will never
#               actually get here, but will stop because of the action associated with the error.
#               But, just in case, this state asks the state machine to exit.
errorDeath:
    default              n errorDeath                               doExit


