#*****************************************************************************
#
# Copyright (C) 2002-2003, International Business Machines Corporation and others.
# All Rights Reserved.
#
#*****************************************************************************
#
# file: rbbirpt.txt
# ICU Break Iterator Rule Parser State Table
#
# This state table is used when reading and parsing a set of RBBI rules
# The rule parser uses a state machine; the data in this file define the
# state transitions that occur for each input character.
#
# *** This file defines the RBBI rule grammar. This is it.
# *** The determination of what is accepted is here.
#
# This file is processed by a perl script "rbbicst.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 rules file, or in between two rules.
#
start:
escaped term ^break-rule-end doExprStart
white_space n start
'$' scan-var-name ^assign-or-rule doExprStart
'!' n rev-option
';' n start # ignore empty rules.
eof exit
default term ^break-rule-end doExprStart
#
# break-rule-end: Returned from doing a break-rule expression.
#
break-rule-end:
';' n start doEndOfRule
white_space n break-rule-end
default errorDeath doRuleError
#
# ! We've just scanned a '!', indicating either a !!key word flag or a
# !Reverse rule.
#
rev-option:
'!' n option-scan1
default reverse-rule ^break-rule-end doReverseDir
option-scan1:
name_start_char n option-scan2 doOptionStart
default errorDeath doRuleError
option-scan2:
name_char n option-scan2
default option-scan3 doOptionEnd
option-scan3:
';' n start
white_space n option-scan3
default errorDeath doRuleError
reverse-rule:
default term ^break-rule-end doExprStart
#
# term. Eat through a single rule character, or a composite thing, which
# could be a parenthesized expression, a variable name, or a Unicode Set.
#
term:
escaped n expr-mod doRuleChar
white_space n term
rule_char n expr-mod doRuleChar
'[' scan-unicode-set ^expr-mod
'(' n term ^expr-mod doLParen
'$' scan-var-name ^term-var-ref
'.' n expr-mod doDotAny
default errorDeath doRuleError
#
# term-var-ref We've just finished scanning a reference to a $variable.
# Check that the variable was defined.
# The variable name scanning is in common with assignment statements,
# so the check can't be done there.
term-var-ref:
default expr-mod doCheckVarDef
#
# expr-mod We've just finished scanning a term, now look for the optional
# trailing '*', '?', '+'
#
expr-mod:
white_space n expr-mod
'*' n expr-cont doUnaryOpStar
'+' n expr-cont doUnaryOpPlus
'?' n expr-cont doUnaryOpQuestion
default expr-cont
#
# expr-cont Expression, continuation. At a point where additional terms are
# allowed, but not required.
#
expr-cont:
escaped term doExprCatOperator
white_space n expr-cont
rule_char term doExprCatOperator
'[' term doExprCatOperator
'(' term doExprCatOperator
'$' term doExprCatOperator
'.' term doExprCatOperator
'/' look-ahead doExprCatOperator
'{' n tag-open doExprCatOperator
'|' n term doExprOrOperator
')' n pop doExprRParen
default pop doExprFinished
#
# look-ahead Scanning a '/', which identifies a break point, assuming that the
# remainder of the expression matches.
#
# Generate a parse tree as if this was a special kind of input symbol
# appearing in an otherwise normal concatenation expression.
#
look-ahead:
'/' n expr-cont-no-slash doSlash
default errorDeath
#
# expr-cont-no-slash Expression, continuation. At a point where additional terms are
# allowed, but not required. Just like
# expr-cont, above, except that no '/'
# look-ahead symbol is permitted.
#
expr-cont-no-slash:
escaped term doExprCatOperator
white_space n expr-cont
rule_char term doExprCatOperator
'[' term doExprCatOperator
'(' term doExprCatOperator
'$' term doExprCatOperator
'.' term doExprCatOperator
'|' n term doExprOrOperator
')' n pop doExprRParen
default pop doExprFinished
#
# tags scanning a '{', the opening delimiter for a tag that identifies
# the kind of match. Scan the whole {dddd} tag, where d=digit
#
tag-open:
white_space n tag-open
digit_char tag-value doStartTagValue
default errorDeath doTagExpectedError
tag-value:
white_space n tag-close
'}' tag-close
digit_char n tag-value doTagDigit
default errorDeath doTagExpectedError
tag-close:
white_space n tag-close
'}' n expr-cont-no-tag doTagValue
default errorDeath doTagExpectedError
#
# expr-cont-no-tag Expression, continuation. At a point where additional terms are
# allowed, but not required. Just like
# expr-cont, above, except that no "{ddd}"
# tagging is permitted.
#
expr-cont-no-tag:
escaped term doExprCatOperator
white_space n expr-cont-no-tag
rule_char term doExprCatOperator
'[' term doExprCatOperator
'(' term doExprCatOperator
'$' term doExprCatOperator
'.' term doExprCatOperator
'/' look-ahead doExprCatOperator
'|' n term doExprOrOperator
')' n pop doExprRParen
default pop doExprFinished
#
# Variable Name Scanning.
#
# The state that branched to here must have pushed a return state
# to go to after completion of the variable name scanning.
#
# The current input character must be the $ that introduces the name.
# The $ is consummed here rather than in the state that first detected it
# so that the doStartVariableName action only needs to happen in one
# place (here), and the other states don't need to worry about it.
#
scan-var-name:
'$' n scan-var-start doStartVariableName
default errorDeath
scan-var-start:
name_start_char n scan-var-body
default errorDeath doVariableNameExpectedErr
scan-var-body:
name_char n scan-var-body
default pop doEndVariableName
#
# scan-unicode-set Unicode Sets are parsed by the the UnicodeSet class.
# Within the RBBI parser, after finding the first character
# of a Unicode Set, we just hand the rule input at that
# point of to the Unicode Set constructor, then pick
# up parsing after the close of the set.
#
# The action for this state invokes the UnicodeSet parser.
#
scan-unicode-set:
'[' n pop doScanUnicodeSet
'p' n pop doScanUnicodeSet
'P' n pop doScanUnicodeSet
default errorDeath
#
# assign-or-rule. A $variable was encountered at the start of something, could be
# either an assignment statement or a rule, depending on whether an '='
# follows the variable name. We get to this state when the variable name
# scanning does a return.
#
assign-or-rule:
white_space n assign-or-rule
'=' n term ^assign-end doStartAssign # variable was target of assignment
default term-var-ref ^break-rule-end # variable was a term in a rule
#
# assign-end This state is entered when the end of the expression on the
# right hand side of an assignment is found. We get here via
# a pop; this state is pushed when the '=' in an assignment is found.
#
# The only thing allowed at this point is a ';'. The RHS of an
# assignment must look like a rule expression, and we come here
# when what is being scanned no longer looks like an expression.
#
assign-end:
';' n start doEndAssign
default errorDeath doRuleErrorAssignExpr
#
# 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