NAME

Text::TokenStream::Role::Stream - role for token-stream classes

SYNOPSIS

    # In some kind of parser class:
    has stream => (
        is => 'ro',
        handles => 'Text::TokenStream::Role::Stream',
    );

DESCRIPTION

This role requires and/or implements methods that provide the machinery for scanning an input string into tokens. It exists as a role so that a parser class can easily delegate those methods to a stream instance.

See Text::TokenStream.

PROVIDED METHODS

collect_all

Takes no arguments. Returns a list of all remaining tokens found in the input.

collect_upto

Takes a single argument indicating a token to match, as with Text::TokenStream::Token#matches. Scans through the input until it finds a token that matches the argument, and returns a list of all tokens before the matching one. If no remaining token in the input matches the argument, behaves as "collect_all".

REQUIRED METHODS

current_position

Should take no arguments, and return the current input position.

err

Should take any number of arguments, and throw an exception that reports an error at the current position.

fill

Should take a non-negative integer argument, and fill the internal buffer with that many tokens (or as many as are available), and return true iff that succeeded.

looking_at

Should take any number of arguments for Text::TokenStream::Token#matches, fill the internal buffer with the right number of elements (returning false if there aren't enough), and return true if each token is matched by the corresponding argument.

next

Should take no elements, and return the next token (or undef if no more elements are available), advancing the current position.

next_of

Should take an argument for Text::TokenStream::Token#matches, ensure that there is at least one token remaining and that it matches that argument (reporting an error if not), and return that token, advancing the current position.

peek

Should take no elements, and return the next token if one exists, without advancing the current position.

skip_optional

Should take an argument for Text::TokenStream::Token#matches, and if there's another token that matches it, advance past that token, and return true; otherwise, it should return false.

token_err

Should take a token, and any number of arguments, and throw an exception that reports an error at the position of the token.

AUTHOR

Aaron Crane, <arc@cpan.org>

COPYRIGHT

Copyright 2021 Aaron Crane.

LICENCE

This library is free software and may be distributed under the same terms as perl itself. See http://dev.perl.org/licenses/.