A. Grammar for Parsers

This is the grammar for parsers, without any Python code mixed in. The complete grammar can be found in parsedesc.g in the Yapps distribution.

parser ParserDescription:
    ignore:      "\\s+"
    ignore:      "#.*?\r?\n"
    token END:   "$"  # $ means end of string
    token ATTR:  "<<.+?>>"
    token STMT:  "{{.+?}}"
    token ID:    '[a-zA-Z_][a-zA-Z_0-9]*'
    token STR:   '[rR]?\'([^\\n\'\\\\]|\\\\.)*\'|[rR]?"([^\\n"\\\\]|\\\\.)*"'

    rule Parser: "parser" ID ":"
                   Options
                   Tokens
                   Rules
                 END 

    rule Options:  ( "option" ":" STR )*
    rule Tokens:   ( "token" ID ":" STR | "ignore"   ":" STR )*
    rule Rules:    ( "rule" ID OptParam ":" ClauseA )*

    rule ClauseA:  ClauseB ( '[|]' ClauseB )*
    rule ClauseB:  ClauseC*
    rule ClauseC:  ClauseD [ '[+]' | '[*]' ]
    rule ClauseD:  STR | ID [ATTR] | STMT
                 | '\\(' ClauseA '\\) | '\\[' ClauseA '\\]'