Php/docs/parle.examples.parser
Parser examples
Example #1 Simple calculator
<?php use Parle\{Parser, ParserException, Lexer, Token};$p = new Parser;$p->token("INTEGER");$p->left("'+' '-' '*' '/'");$p->push("start", "exp");$prod_add = $p->push("exp", "exp '+' exp");$prod_sub = $p->push("exp", "exp '-' exp");$prod_mul = $p->push("exp", "exp '*' exp");$prod_div = $p->push("exp", "exp '/' exp");$p->push("exp", "INTEGER"); /* Production index unused. */$p->build();$lex = new Lexer;$lex->push("[+]", $p->tokenId("'+'"));$lex->push("[-]", $p->tokenId("'-'"));$lex->push("[*]", $p->tokenId("'*'"));$lex->push("[/]", $p->tokenId("'/'"));$lex->push("\\d+", $p->tokenId("INTEGER"));$lex->push("\\s+", Token::SKIP);$lex->build();$exp = array( "1 + 1", "33 / 10", "100 * 45", "17 - 45",);foreach ($exp as $in) { if (!$p->validate($in, $lex)) { throw new ParserException("Failed to validate input"); } $p->consume($in, $lex); while (Parser::ACTION_ERROR != $p->action && Parser::ACTION_ACCEPT != $p->action) { switch ($p->action) { case Parser::ACTION_ERROR: throw new ParserException("Parser error"); break; case Parser::ACTION_SHIFT: case Parser::ACTION_GOTO: case Parser::ACTION_ACCEPT: break; case Parser::ACTION_REDUCE: switch ($p->reduceId) { case $prod_add: $l = $p->sigil(0); $r = $p->sigil(2); echo "$l + $r = " . ($l + $r) . "\n"; break; case $prod_sub: $l = $p->sigil(0); $r = $p->sigil(2); echo "$l - $r = " . ($l - $r) . "\n"; break; case $prod_mul: $l = $p->sigil(0); $r = $p->sigil(2); echo "$l * $r = " . ($l * $r) . "\n"; break; case $prod_div: $l = $p->sigil(0); $r = $p->sigil(2); echo "$l / $r = " . ($l / $r) . "\n"; break; } break; } $p->advance(); }}
Example #2 Parse words out from a sentence
<?phpuse Parle\{Lexer, Token, Parser, ParserException};$p = new Parser;$p->token("WORD");$p->push("START", "SENTENCE");$p->push("SENTENCE", "WORDS");$prod_word_0 = $p->push("WORDS", "WORDS WORD");$prod_word_1 = $p->push("WORDS", "WORD");$p->build();$lex = new Lexer;$lex->push("[^\s]{-}[\.,\:\;\?]+", $p->tokenId("WORD"));$lex->push("[\s\.,\:\;\?]+", Token::SKIP);$lex->build();$in = "Dis-moi où est ton papa?";$p->consume($in, $lex);do { switch ($p->action) { case Parser::ACTION_ERROR: throw new ParserException("Error"); break; case Parser::ACTION_SHIFT: case Parser::ACTION_GOTO: /* var_dump($p->trace());*/ break; case Parser::ACTION_REDUCE: $rid = $p->reduceId(); if ($rid == $prod_word_1) { var_dump($p->sigil(0)); } if ($rid == $prod_word_0) { var_dump($p->sigil(1)); } break; } $p->advance();} while (Parser::ACTION_ACCEPT != $p->action);
