This is the parser for CRE in TPE format.
Assert <- ASSERT '(' Sequence ')'
Atom <- 'any' / LITERAL / SINGLE / ZERO
BackRef <- 'REF' '(' (DIGIT / IDENTIFIER) ')'
Capture <- '{' Sequence ('as' IDENTIFIER)? '}'
Char <- CHAR / CHAR_LITERAL / SINGLE
# Examples: a 0x00 &201c &space
Choice <- 'either' Sequence ('or' Sequence)+
Class <- 'chars' '[' ClassItem+ ']'
ClassItem <- Char '-' Char / Char / CLUMP / NegatableInClass
Definition <- IDENTIFIER '=' Sequence
Flags <- 'flags' '(' IDENTIFIER* ')'
Group <- '(' Sequence ')'
Negatable <- '!'? (Class / Assert / PERL / POSIX / UNICODE)
NegatableInClass <- '!'? (PERL / POSIX / UNICODE)
# Examples: word !digit :alnum !:space ::Greek !::Greek
Primary <- Atom
/ Negatable
/ IDENTIFIER ! '='
/ Group
/ Capture
/ Choice
/ BackRef
RepeatRange <- DIGIT? '..' DIGIT?
RepeatSpec <- '(' MODIFIER?
( RepeatRange / DIGIT / '?' / '*' / '+' )
')'
Sequence <- Suffix+
SimpleRepeat <- '?' / '*' / '+'
/ '??' / '**' / '++'
Start <- Flags? (Sequence / Definition+) !.
Suffix <- Primary ( SimpleRepeat / '^' DIGIT / '^' RepeatSpec )?
Last modified: 2013-01-20 00:37:12 -0800