<?php
///////////////////////////////
/// Utility regex constants ///
///////////////////////////////
const LIB = '(?(DEFINE)
(?<singleQuotedString>\'[^\\\\\']*+(?:\\\\.[^\\\\\']*+)*+\')
(?<doubleQuotedString>"[^\\\\"]*+(?:\\\\.[^\\\\"]*+)*+")
(?<string>(?&singleQuotedString)|(?&doubleQuotedString))
(?<comment>/\*[^*]*+(?:\*(?!/)[^*]*+)*+\*/)
(?<code>\{[^\'"/{}]*+(?:(?:(?&string)|(?&comment)|(?&code)|/)[^\'"/{}]*+)*+})
)';
const PARAMS = '\[(?<params>[^[\]]*+(?:\[(?¶ms)\][^[\]]*+)*+)\]';
const ARGS = '\((?<args>[^()]*+(?:\((?&args)\)[^()]*+)*+)\)';
///////////////////////////////
/// Preprocessing functions ///
///////////////////////////////
function preprocessGrammar($code) {
$code = resolveNodes($code);
$code = resolveMacros($code);
$code = resolveStackAccess($code);
return $code;
}
function resolveNodes($code) {
return preg_replace_callback(
'~\b(?<name>[A-Z][a-zA-Z_\\\\]++)\s*' . PARAMS . '~',
function($matches) {
// recurse
$matches['params'] = resolveNodes($matches['params']);
$params = magicSplit(
'(?:' . PARAMS . '|' . ARGS . ')(*SKIP)(*FAIL)|,',
$matches['params']
);
$paramCode = '';
foreach ($params as $param) {
$paramCode .= $param . ', ';
}
return 'new ' . $matches['name'] . '(' . $paramCode . 'attributes())';
},
$code
);
}
function resolveMacros($code) {
return preg_replace_callback(
'~\b(?<!::|->)(?!array\()(?<name>[a-z][A-Za-z]++)' . ARGS . '~',
function($matches) {
// recurse
$matches['args'] = resolveMacros($matches['args']);
$name = $matches['name'];
$args = magicSplit(
'(?:' . PARAMS . '|' . ARGS . ')(*SKIP)(*FAIL)|,',
$matches['args']
);
if ('attributes' === $name) {
assertArgs(0, $args, $name);
return '$this->startAttributeStack[#1] + $this->endAttributes';
}
if ('stackAttributes' === $name) {
assertArgs(1, $args, $name);
return '$this->startAttributeStack[' . $args[0] . ']'
. ' + $this->endAttributeStack[' . $args[0] . ']';
}
if ('init' === $name) {
return '$$ = array(' . implode(', ', $args) . ')';
}
if ('push' === $name) {
assertArgs(2, $args, $name);
return $args[0] . '[] = ' . $args[1] . '; $$ = ' . $args[0];
}
if ('pushNormalizing' === $name) {
assertArgs(2, $args, $name);
return 'if (is_array(' . $args[1] . ')) { $$ = array_merge(' . $args[0] . ', ' . $args[1] . '); }'
. ' else { ' . $args[0] . '[] = ' . $args[1] . '; $$ = ' . $args[0] . '; }';
}
if ('toArray' == $name) {
assertArgs(1, $args, $name);
return 'is_array(' . $args[0] . ') ? ' . $args[0] . ' : array(' . $args[0] . ')';
}
if ('parseVar' === $name) {
assertArgs(1, $args, $name);
return 'substr(' . $args[0] . ', 1)';
}
if ('parseEncapsed' === $name) {
assertArgs(3, $args, $name);
return 'foreach (' . $args[0] . ' as $s) { if ($s instanceof Node\Scalar\EncapsedStringPart) {'
. ' $s->value = Node\Scalar\String_::parseEscapeSequences($s->value, ' . $args[1] . ', ' . $args[2] . '); } }';
}
if ('makeNop' === $name) {
assertArgs(3, $args, $name);
return '$startAttributes = ' . $args[1] . ';'
. ' if (isset($startAttributes[\'comments\']))'
. ' { ' . $args[0] . ' = new Stmt\Nop($startAttributes + ' . $args[2] . '); }'
. ' else { ' . $args[0] . ' = null; }';
}
if ('makeZeroLengthNop' == $name) {
assertArgs(2, $args, $name);
return '$startAttributes = ' . $args[1] . ';'
. ' if (isset($startAttributes[\'comments\']))'
. ' { ' . $args[0] . ' = new Stmt\Nop($this->createCommentNopAttributes($startAttributes[\'comments\'])); }'
. ' else { ' . $args[0] . ' = null; }';
}
if ('strKind' === $name) {
assertArgs(1, $args, $name);
return '(' . $args[0] . '[0] === "\'" || (' . $args[0] . '[1] === "\'" && '
. '(' . $args[0] . '[0] === \'b\' || ' . $args[0] . '[0] === \'B\')) '
. '? Scalar\String_::KIND_SINGLE_QUOTED : Scalar\String_::KIND_DOUBLE_QUOTED)';
}
if ('prependLeadingComments' === $name) {
assertArgs(1, $args, $name);
return '$attrs = $this->startAttributeStack[#1]; $stmts = ' . $args[0] . '; '
. 'if (!empty($attrs[\'comments\'])) {'
. '$stmts[0]->setAttribute(\'comments\', '
. 'array_merge($attrs[\'comments\'], $stmts[0]->getAttribute(\'comments\', []))); }';
}
return $matches[0];
},
$code
);
}
function assertArgs($num, $args, $name) {
if ($num != count($args)) {
die('Wrong argument count for ' . $name . '().');
}
}
function resolveStackAccess($code) {
$code = preg_replace('/\$\d+/', '$this->semStack[$0]', $code);
$code = preg_replace('/#(\d+)/', '$$1', $code);
return $code;
}
function removeTrailingWhitespace($code) {
$lines = explode("\n", $code);
$lines = array_map('rtrim', $lines);
return implode("\n", $lines);
}
//////////////////////////////
/// Regex helper functions ///
//////////////////////////////
function regex($regex) {
return '~' . LIB . '(?:' . str_replace('~', '\~', $regex) . ')~';
}
function magicSplit($regex, $string) {
$pieces = preg_split(regex('(?:(?&string)|(?&comment)|(?&code))(*SKIP)(*FAIL)|' . $regex), $string);
foreach ($pieces as &$piece) {
$piece = trim($piece);
}
if ($pieces === ['']) {
return [];
}
return $pieces;
}
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