TAP::Parser::Grammar - 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,