对编译原理有兴趣的进
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。
请提建议。代码放不下，分两页。下载地址 http://download.csdn.net/detail/xuzuning/4529066
include 'ttrie.php';
class Rule extends TTrie {
public $rule = array();
public $savematch = 0;
function __construct($s='') {
$this->set( array(
' ' => 'Separated',
"\r\n" => 'set_rule',
"\n" => 'set_rule',
"\t" => 'Separated',
'->' => 'Separated',
'→' => 'Separated',
'|' => 'set_parallel_rule',
));
$this->match($s);
if($this->rule[0][0] == $this->rule[0][1]) {
if(count($this->rule[0]) == 2) $this->rule[0][0] .= "'";
else array_unshift($this->rule, array($this->rule[0][0]."'", $this->rule[0][0]));
}else {
$c = $this->rule[0][0];
$n = 0;
foreach($this->rule as $r) if($r[0] == $c) $n++;
if($n > 1) array_unshift($this->rule, array($this->rule[0][0]."'", $this->rule[0][0]));
}
}
function Separated() {
}
function set_rule() {
$this->rule[] = $this->buffer;
$this->buffer = array();
}
function set_parallel_rule() {
$t = $this->buffer[0];
$this->set_rule();
$this->buffer[] = $t;
}
}
class Grammar {
var $closure = array();
var $first = array();
var $follow = array();
var $rule = array();
var $identifier = array();
var $leay = array();
var $forecast = array();
var $stack = array();
var $ll = 'LL(0)';
var $lr = 'LR(0)';
function __construct($s='') {
$p = new Rule($s);
$this->rule = $p->rule;
$this->set_grammar();
}
function set_grammar() {
foreach($this->rule as $rule) {
if(! in_array($rule[0], $this->identifier)) $this->identifier[] = $rule[0];
}
foreach($this->rule as $rule) {
foreach($rule as $v)
if(! in_array($v, $this->identifier) && ! in_array($v, $this->leay))
$this->leay[] = $v;
}
$this->set_first();
$this->set_follow();
$this->set_closure();
$this->set_select();
$this->set_forecast();
}
function set_first() {
foreach($this->rule as $rule) $this->first[$rule[0]] = array();
//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
foreach($this->rule as $v) {
if(in_array($v[1], $this->leay)) $this->first[$v[0]][] = $v[1];
}
//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
do {
$t = serialize($this->first);
foreach($this->rule as $rule) {
for($i=1; $i<count($rule); $i++) {
$v = $rule[$i];
if(in_array($v, $this->identifier)) {
$this->first[$rule[0]] = array_unique(array_merge($this->first[$rule[0]], $this->first[$v]));
if(! in_array('#', $this->first[$v])) break;
}else break;
}
}
}while($t != serialize($this->first));
}
function set_follow() {
foreach($this->rule as $rule) $this->follow[$rule[0]] = array();
//直接收取 形如 …Ua… 的，把a直接收入到Follow(U)中
foreach($this->rule as $rule) {
for($i=1; $i<count($rule)-1; $i++) {
if(in_array($rule[$i], $this->identifier) && in_array($rule[$i+1], $this->leay))
$this->follow[$rule[$i]][] = $rule[$i+1];
}
if(in_array($rule[$i], $this->identifier)) $this->follow[$rule[$i]][] = '#';
}
foreach($this->follow as &$v) if(! $v) $v[] = '#';
//直接收取 形如 …UP…(P是非终结符)的，把First(P)中非ε收入到Follow(U)中
foreach($this->rule as $rule) {
for($i=1; $i<count($rule)-1; $i++) {
if(in_array($rule[$i], $this->identifier) && in_array($rule[$i+1], $this->identifier)) {
$this->follow[$rule[$i]] = array_unique(array_merge($this->follow[$rule[$i]], array_diff($this->first[$rule[$i+1]], array('#'))));
}
}
}
//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
do {
$t = serialize($this->follow);
foreach($this->rule as $rule) {
$s = $rule[0];
$d = end($rule);
if(in_array($d, $this->leay)) continue;
$p = prev($rule);
if(in_array($p, $this->leay)) $this->follow[$d] = array_unique(array_merge($this->follow[$d], $this->follow[$s]));
elseif(in_array('#', $this->follow[$d])) $this->follow[$p] = array_unique(array_merge($this->follow[$p], $this->follow[$s]));
}
}while($t != serialize($this->follow));
}
function set_closure() {
$shift = array();
$this->closure[0][] = array('offs' => 1, 'rule' => 0);
for($i=0 ; $i < count($this->closure); $i++) {
$cnt = count($this->closure);
//构造闭包 closure
$ex = array();
$j = 0;
$tmp = array();
do {
$size = count($this->closure[$i]);
for($j=0; $j<count($this->closure[$i]); $j++) {
$dfa = $this->closure[$i][$j];
$rule = $this->rule[$dfa['rule']];
if(isset($rule[$dfa['offs']])) {
$ch = $ex[] = $rule[$dfa['offs']];
}
foreach($this->rule as $r=>$rule) {
if(in_array($rule[0], $ex)) {
$t = array('offs' => 1, 'rule' => $r);
if(!isset($tmp[$r][1])) $this->closure[$i][] = $t;
$tmp[$r][1] = 1;
}
}
}
}while(count($this->closure[$i]) != $size); //直到不再增大
//判断状态转向 go
$out = array();
foreach($this->closure[$i] as $k=>$dfa) {
$rule = $this->rule[$dfa['rule']];
if(isset($rule[$dfa['offs']])) {
$t = "$dfa[rule],$dfa[offs]";
$ch = $rule[$dfa['offs']];
$this->closure[$i][$k]['char'] = $ch;
if(isset($out[$ch])) $shift[$t] = $out[$ch];
if(isset($shift[$t])) {
$this->closure[$i][$k]['target'] = $shift[$t];
$dfa['offs']++;
if(!$this->in_closure($dfa, $this->closure[$shift[$t]])) $this->closure[$shift[$t]][] = $dfa;
} else {
$cnt = count($this->closure);
$this->closure[$i][$k]['target'] = $cnt;
$shift[$t] = $cnt;
$dfa['offs']++;
$this->closure[count($this->closure)][] = $dfa;
$out[$ch] = $cnt;
}
}
}
//构造状态转换表
foreach($this->closure[$i] as $k=>$dfa) {
if(isset($dfa['target'])) {
$v = $dfa['char'];
if(in_array($v, $this->identifier)) $this->goto[$i][$v] = $dfa['target'];
else {
$this->action[$i][$v][] = "S$dfa[target]";
$this->request[$i][$v] = $dfa['rule'];
}
} else {
$ch = $this->rule[$dfa['rule']][0];
foreach($this->follow[$ch] as $v) {
$this->action[$i][$v][] = "r$dfa[rule]";
$this->request[$i][$v] = $dfa['rule'];
}
}
}
foreach($this->action[$i] as $c=>$v) {
$v = array_unique($v);
if(count($v) > 1) $this->lr = 'SLR(1)';
$this->action[$i][$c] = $v;
}
}
}
function in_closure($t, $s) {
foreach($s as $r) if($t['offs'] == $r['offs'] && $t['rule'] == $r['rule']) return true;
return false;
return in_array(serialize($t), array_map('serialize', $s));
}
function set_select() {
foreach($this->rule as $i=>$rule) {
$y = array($rule[1]);
if(in_array($y[0], $this->leay)) {
if($y[0] != '#') {
$this->select[$i] = $y;
continue;
}
}else $y = $this->first[$rule[1]];
$x = $this->follow[$rule[0]];
//SELECT(X->Y)=(FIRST(Y)-{ε})并FOLLOW(X)
$this->select[$i] = array_unique( array_merge(array_diff($y, array('#')), $x) );
}
}
/**
* 构造预测分析表
**/
function set_forecast() {
foreach($this->select as $i=>$r) {
$c = $this->rule[$i][0];
$v = array_reverse(array_slice($this->rule[$i], 1));
foreach($r as $k) {
$this->forecast[$c][$k][] = $v;
}
}
//检查冲突
foreach($this->forecast as $c=>$r) {
foreach($r as $k) {
if(count($k) > 1) {
$this->ll = 'LL(1)';
}
}
}
}
