faveo/vendor/nikic/php-parser/grammar/README.md

What do all those files mean?

• php5.y: PHP 5 grammar written in a pseudo language
• php7.y: PHP 7 grammar written in a pseudo language
• tokens.y: Tokens definition shared between PHP 5 and PHP 7 grammars
• parser.template: A kmyacc parser prototype file for PHP
• tokens.template: A kmyacc prototype file for the Tokens class
• rebuildParsers.php: Preprocesses the grammar and builds the parser using kmyacc

.phpy pseudo language

The .y file is a normal grammar in kmyacc (yacc) style, with some transformations applied to it:

• Nodes are created using the syntax Name[..., ...]. This is transformed into new Name(..., ..., attributes())
• Some function-like constructs are resolved (see rebuildParsers.php for a list)

Building the parser

Run php grammar/rebuildParsers.php to rebuild the parsers. Additional options:

• The KMYACC environment variable can be used to specify an alternative kmyacc binary. By default the phpyacc dev dependency will be used. To use the original kmyacc, you need to compile moriyoshi's fork.
• The --debug option enables emission of debug symbols and creates the y.output file.
• The --keep-tmp-grammar option preserves the preprocessed grammar file.