本帖最后由 xuzuning 于 2012-08-27 16:40:33 编辑 最近尝试做了文法分析的东东，问题较多。
include 'ttrie.php';<br><br>class Rule extends TTrie {<br> public $rule = array();<br> public $savematch = 0;<br><br> function __construct($s='') {<br> $this->set( array(<br> ' ' => 'Separated',<br> "\r\n" => 'set_rule',<br> "\n" => 'set_rule',<br> "\t" => 'Separated',<br> '->' => 'Separated',<br> '→' => 'Separated',<br> '|' => 'set_parallel_rule',<br> ));<br> $this->match($s);<br> if($this->rule[0][0] == $this->rule[0][1]) {<br> if(count($this->rule[0]) == 2) $this->rule[0][0] .= "'";<br> else array_unshift($this->rule, array($this->rule[0][0]."'", $this->rule[0][0]));<br> }else {<br> $c = $this->rule[0][0];<br> $n = 0;<br> foreach($this->rule as $r) if($r[0] == $c) $n++;<br> if($n > 1) array_unshift($this->rule, array($this->rule[0][0]."'", $this->rule[0][0]));<br> }<br> }<br> function Separated() {<br> }<br> function set_rule() {<br> $this->rule[] = $this->buffer;<br> $this->buffer = array();<br> }<br> function set_parallel_rule() {<br> $t = $this->buffer[0];<br> $this->set_rule();<br> $this->buffer[] = $t;<br> }<br>}<br><br><br>class Grammar {<br> var $closure = array();<br> var $first = array();<br> var $follow = array();<br> var $rule = array();<br> var $identifier = array();<br> var $leay = array();<br> var $forecast = array();<br> var $stack = array();<br> var $ll = 'LL(0)';<br> var $lr = 'LR(0)';<br><br> function __construct($s='') {<br> $p = new Rule($s);<br> $this->rule = $p->rule;<br> $this->set_grammar();<br> }<br><br> function set_grammar() {<br> foreach($this->rule as $rule) {<br> if(! in_array($rule[0], $this->identifier)) $this->identifier[] = $rule[0];<br> }<br> foreach($this->rule as $rule) {<br> foreach($rule as $v)<br> if(! in_array($v, $this->identifier) && ! in_array($v, $this->leay))<br> $this->leay[] = $v;<br> }<br> $this->set_first();<br> $this->set_follow();<br> $this->set_closure();<br> $this->set_select();<br> $this->set_forecast();<br> }<br> function set_first() {<br> foreach($this->rule as $rule) $this->first[$rule[0]] = array();<br> //直接收取 形如U->a…的产生式（其中a是终结符），把a收入到First(U)中<br> foreach($this->rule as $v) {<br> if(in_array($v[1], $this->leay)) $this->first[$v[0]][] = $v[1];<br> }<br> //反复传递 形入U->P1P2P3…Pn的产生式（其中P是非终结符），应先把First(P1)中的全部内容传送到First(U)中,如果P1中有ε，把First(P2)中的内容传送到First(U)中,类推直到Pi中无ε<br> do {<br> $t = serialize($this->first);<br> foreach($this->rule as $rule) {<br> for($i=1; $i<count></count> $v = $rule[$i];<br> if(in_array($v, $this->identifier)) {<br> $this->first[$rule[0]] = array_unique(array_merge($this->first[$rule[0]], $this->first[$v]));<br> if(! in_array('#', $this->first[$v])) break;<br> }else break;<br> }<br> }<br> }while($t != serialize($this->first));<br> }<br> function set_follow() {<br> foreach($this->rule as $rule) $this->follow[$rule[0]] = array();<br> //直接收取 形如 …Ua… 的，把a直接收入到Follow(U)中<br> foreach($this->rule as $rule) {<br> for($i=1; $i<count></count> if(in_array($rule[$i], $this->identifier) && in_array($rule[$i+1], $this->leay))<br> $this->follow[$rule[$i]][] = $rule[$i+1];<br> }<br> if(in_array($rule[$i], $this->identifier)) $this->follow[$rule[$i]][] = '#';<br> }<br> foreach($this->follow as &$v) if(! $v) $v[] = '#';<br> //直接收取 形如 …UP…(P是非终结符)的，把First(P)中非ε收入到Follow(U)中<br> foreach($this->rule as $rule) {<br> for($i=1; $i<count></count> if(in_array($rule[$i], $this->identifier) && in_array($rule[$i+1], $this->identifier)) {<br> $this->follow[$rule[$i]] = array_unique(array_merge($this->follow[$rule[$i]], array_diff($this->first[$rule[$i+1]], array('#'))));<br> }<br> }<br> }<br> //反复传递 形如U－>aP的(P是非终结符)或U->aPQ(P,Q为非终结符且Q中含ε)，应把Follow(U)中的全部内容传送到Follow(P)中<br> do {<br> $t = serialize($this->follow);<br> foreach($this->rule as $rule) {<br> $s = $rule[0];<br> $d = end($rule);<br> if(in_array($d, $this->leay)) continue;<div class="clear">
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