TAP::Parser::Grammar - A grammar for the Test Anything Protocol.
Version 3.42
use TAP::Parser::Grammar;
my $grammar = $self->make_grammar({
iterator => $tap_parser_iterator,
parser => $tap_parser,
version => 12,
});
my $result = $grammar->tokenize;
TAP::Parser::Grammar tokenizes lines from a the TAP::Parser::Iterator manpage and
constructs the TAP::Parser::Result manpage 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).
my $grammar = TAP::Parser::Grammar->new({
iterator => $iterator,
parser => $parser,
version => $version,
});
Returns the TAP::Parser manpage 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).
$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.
my $token = $grammar->tokenize;
This method will return a the TAP::Parser::Result manpage object representing the
current line of TAP.
my @types = $grammar->token_types;
Returns the different types of tokens which this grammar can parse.
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/^#(.*)/ .
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);
}
NOTE: This grammar is slightly out of date.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 the TAP::Parser manpage 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
the TAP::Parser::Result::Unknown manpage. 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}
Please see SUBCLASSING in the TAP::Parser manpage for a subclassing overview.
If you really want to subclass the TAP::Parser manpage's grammar the best thing to
do is read through the code. There's no easy way of summarizing it here.
the TAP::Object manpage,
the TAP::Parser manpage,
the TAP::Parser::Iterator manpage,
the TAP::Parser::Result manpage,
|