TAP::Parser::Grammar - man - phpman

NAME
    TAP::Parser::Grammar - A grammar for the Test Anything Protocol.

VERSION
    Version 3.43

SYNOPSIS
      use TAP::Parser::Grammar;
      my $grammar = $self->make_grammar({
        iterator => $tap_parser_iterator,
        parser   => $tap_parser,
        version  => 12,
      });

      my $result = $grammar->tokenize;

DESCRIPTION
    "TAP::Parser::Grammar" tokenizes lines from a TAP::Parser::Iterator and constructs
    TAP::Parser::Result subclasses to represent the tokens.

    Do not attempt to use this class directly. It won't make sense. It's mainly here to ensure that
    we will be able to have pluggable grammars when TAP is expanded at some future date (plus, this
    stuff was really cluttering the parser).

METHODS
  Class Methods
   "new"
      my $grammar = TAP::Parser::Grammar->new({
          iterator => $iterator,
          parser   => $parser,
          version  => $version,
      });

    Returns TAP::Parser grammar object that will parse the TAP stream from the specified iterator.
    Both "iterator" and "parser" are required arguments. If "version" is not set it defaults to 12
    (see "set_version" for more details).

  Instance Methods
   "set_version"
      $grammar->set_version(13);

    Tell the grammar which TAP syntax version to support. The lowest supported version is 12.
    Although 'TAP version' isn't valid version 12 syntax it is accepted so that higher version
    numbers may be parsed.

   "tokenize"
      my $token = $grammar->tokenize;

    This method will return a TAP::Parser::Result object representing the current line of TAP.

   "token_types"
      my @types = $grammar->token_types;

    Returns the different types of tokens which this grammar can parse.

   "syntax_for"
      my $syntax = $grammar->syntax_for($token_type);

    Returns a pre-compiled regular expression which will match a chunk of TAP corresponding to the
    token type. For example (not that you should really pay attention to this,
    "$grammar->syntax_for('comment')" will return "qr/^#(.*)/".

   "handler_for"
      my $handler = $grammar->handler_for($token_type);

    Returns a code reference which, when passed an appropriate line of TAP, returns the lexed token
    corresponding to that line. As a result, the basic TAP parsing loop looks similar to the
    following:

     my @tokens;
     my $grammar = TAP::Grammar->new;
     LINE: while ( defined( my $line = $parser->_next_chunk_of_tap ) ) {
         for my $type ( $grammar->token_types ) {
             my $syntax  = $grammar->syntax_for($type);
             if ( $line =~ $syntax ) {
                 my $handler = $grammar->handler_for($type);
                 push @tokens => $grammar->$handler($line);
                 next LINE;
             }
         }
         push @tokens => $grammar->_make_unknown_token($line);
     }

TAP GRAMMAR
    NOTE: This grammar is slightly out of date. There's still some discussion about it and a new one
    will be provided when we have things better defined.

    The TAP::Parser does not use a formal grammar because TAP is essentially a stream-based
    protocol. In fact, it's quite legal to have an infinite stream. For the same reason that we
    don't apply regexes to streams, we're not using a formal grammar here. Instead, we parse the TAP
    in lines.

    For purposes for forward compatibility, any result which does not match the following grammar is
    currently referred to as TAP::Parser::Result::Unknown. It is *not* a parse error.

    A formal grammar would look similar to the following:

     (*
         For the time being, I'm cheating on the EBNF by allowing
         certain terms to be defined by POSIX character classes by
         using the following syntax:

           digit ::= [:digit:]

         As far as I am aware, that's not valid EBNF.  Sue me.  I
         didn't know how to write "char" otherwise (Unicode issues).
         Suggestions welcome.
     *)

     tap            ::= version? { comment | unknown } leading_plan lines
                        |
                        lines trailing_plan {comment}

     version        ::= 'TAP version ' positiveInteger {positiveInteger} "\n"

     leading_plan   ::= plan skip_directive? "\n"

     trailing_plan  ::= plan "\n"

     plan           ::= '1..' nonNegativeInteger

     lines          ::= line {line}

     line           ::= (comment | test | unknown | bailout ) "\n"

     test           ::= status positiveInteger? description? directive?

     status         ::= 'not '? 'ok '

     description    ::= (character - (digit | '#')) {character - '#'}

     directive      ::= todo_directive | skip_directive

     todo_directive ::= hash_mark 'TODO' ' ' {character}

     skip_directive ::= hash_mark 'SKIP' ' ' {character}

     comment        ::= hash_mark {character}

     hash_mark      ::= '#' {' '}

     bailout        ::= 'Bail out!' {character}

     unknown        ::= { (character - "\n") }

     (* POSIX character classes and other terminals *)

     digit              ::= [:digit:]
     character          ::= ([:print:] - "\n")
     positiveInteger    ::= ( digit - '0' ) {digit}
     nonNegativeInteger ::= digit {digit}

SUBCLASSING
    Please see "SUBCLASSING" in TAP::Parser for a subclassing overview.

    If you *really* want to subclass TAP::Parser's grammar the best thing to do is read through the
    code. There's no easy way of summarizing it here.

SEE ALSO
    TAP::Object, TAP::Parser, TAP::Parser::Iterator, TAP::Parser::Result,