<?php
namespace kch42\ste;
/*
* Class: Transcompiler
* Contains the STE transcompiler. You'll only need this, if you want to manually transcompile a STE template.
*/
class Transcompiler {
private static $builtins = NULL;
public static function tempvar($typ) {
return $typ . '_' . str_replace('.', '_', uniqid('', true));
}
public static function init_builtins() {
if(self::$builtins !== NULL) {
return;
}
self::$builtins = array(
"if" => function($ast) {
$output = "";
$condition = array();
$then = NULL;
$else = NULL;
foreach($ast->sub as $node) {
if(($node instanceof TagNode) and ($node->name == "then")) {
$then = $node->sub;
} else if(($node instanceof TagNode) and ($node->name == "else")) {
$else = $node->sub;
} else {
$condition[] = $node;
}
}
if($then === NULL) {
throw new ParseCompileError("self::Transcompile error: Missing <ste:then> in <ste:if>.", $ast->tpl, $ast->offset);
}
$output .= "\$outputstack[] = \"\";\n\$outputstack_i++;\n";
$output .= self::_transcompile($condition);
$output .= "\$outputstack_i--;\nif(\$ste->evalbool(array_pop(\$outputstack)))\n{\n";
$output .= self::indent_code(self::_transcompile($then));
$output .= "\n}\n";
if($else !== NULL) {
$output .= "else\n{\n";
$output .= self::indent_code(self::_transcompile($else));
$output .= "\n}\n";
}
return $output;
},
"cmp" => function($ast) {
$operators = array(
array('eq', '=='),
array('neq', '!='),
array('lt', '<'),
array('lte', '<='),
array('gt', '>'),
array('gte', '>=')
);
$code = "";
if(isset($ast->params["var_b"])) {
list($val, $pre) = self::_transcompile($ast->params["var_b"], true);
$code .= $pre;
$b = '$ste->get_var_by_name(' . $val . ')';
} else if(isset($ast->params["text_b"])) {
list($b, $pre) = self::_transcompile($ast->params["text_b"], true);
$code .= $pre;
} else {
throw new ParseCompileError("self::Transcompile error: neiter var_b nor text_b set in <ste:cmp>.", $ast->tpl, $ast->offset);
}
if(isset($ast->params["var_a"])) {
list($val, $pre) = self::_transcompile($ast->params["var_a"], true);
$code .= $pre;
$a = '$ste->get_var_by_name(' . $val . ')';
} else if(isset($ast->params["text_a"])) {
list($a, $pre) = self::_transcompile($ast->params["text_a"], true);
$code .= $pre;
} else {
throw new ParseCompileError("self::Transcompile error: neiter var_a nor text_a set in <ste:cmp>.", $ast->tpl, $ast->offset);
}
if(!isset($ast->params["op"])) {
throw new ParseCompileError("self::Transcompile error: op not given in <ste:cmp>.", $ast->tpl, $ast->offset);
}
if((count($ast->params["op"]) == 1) and ($ast->params["op"][0] instanceof TextNode)) {
/* Operator is known at compile time, this saves *a lot* of output code! */
$op = trim($ast->params["op"][0]->text);
$op_php = NULL;
foreach($operators as $v) {
if($v[0] == $op) {
$op_php = $v[1];
break;
}
}
if($op_php === NULL) {
throw new ParseCompileError("self::Transcompile Error: Unknown operator in <ste:cmp>", $ast->tpl, $ast->offset);
}
$code .= "\$outputstack[\$outputstack_i] .= (($a) $op_php ($b)) ? 'yes' : '';\n";
} else {
list($val, $pre) = self::_transcompile($ast->params["op"], true);
$code .= $pre . "switch(trim(" . $val . "))\n{\n\t";
$code .= implode("", array_map(
function($op) use ($a,$b)
{
list($op_stetpl, $op_php) = $op;
return "case '$op_stetpl':\n\t\$outputstack[\$outputstack_i] .= (($a) $op_php ($b)) ? 'yes' : '';\n\tbreak;\n\t";
}, $operators
));
$code .= "default: throw new \\kch42\\ste\\RuntimeError('Unknown operator in <ste:cmp>.');\n}\n";
}
return $code;
},
"not" => function($ast) {
$code = "\$outputstack[] = '';\n\$outputstack_i++;\n";
$code .= self::_transcompile($ast->sub);
$code .= "\$outputstack_i--;\n\$outputstack[\$outputstack_i] .= (!\$ste->evalbool(array_pop(\$outputstack))) ? 'yes' : '';\n";
return $code;
},
"even" => function($ast) {
$code = "\$outputstack[] = '';\n\$outputstack_i++;\n";
$code .= self::_transcompile($ast->sub);
$code .= "\$outputstack_i--;\n\$tmp_even = array_pop(\$outputstack);\n\$outputstack[\$outputstack_i] .= (is_numeric(\$tmp_even) and (\$tmp_even % 2 == 0)) ? 'yes' : '';\n";
return $code;
},
"for" => function($ast) {
$code = "";
$loopname = self::tempvar("forloop");
if(empty($ast->params["start"])) {
throw new ParseCompileError("self::Transcompile error: Missing 'start' parameter in <ste:for>.", $ast->tpl, $ast->offset);
}
list($val, $pre) = self::_transcompile($ast->params["start"], true);
$code .= $pre;
$code .= "\$${loopname}_start = " . $val . ";\n";
if(empty($ast->params["stop"])) {
throw new ParseCompileError("self::Transcompile error: Missing 'end' parameter in <ste:for>.", $ast->tpl, $ast->offset);
}
list($val, $pre) = self::_transcompile($ast->params["stop"], true);
$code .= $pre;
$code .= "\$${loopname}_stop = " . $val . ";\n";
$step = NULL; /* i.e. not known at compilation time */
if(empty($ast->params["step"])) {
$step = 1;
} else if((count($ast->params["step"]) == 1) and ($ast->params["step"][0] instanceof TextNode)) {
$step = $ast->params["step"][0]->text + 0;
} else {
list($val, $pre) = self::_transcompile($ast->params["step"], true);
$code .= $pre;
$code .= "\$${loopname}_step = " . $val . ";\n";
}
if(!empty($ast->params["counter"])) {
list($val, $pre) = self::_transcompile($ast->params["counter"], true);
$code .= $pre;
$code .= "\$${loopname}_countername = " . $val . ";\n";
}
$loopbody = empty($ast->params["counter"]) ? "" : "\$ste->set_var_by_name(\$${loopname}_countername, \$${loopname}_counter);\n";
$loopbody .= self::_transcompile($ast->sub);
$loopbody = self::indent_code("{\n" . self::loopbody(self::indent_code($loopbody)) . "\n}\n");
if($step === NULL) {
$code .= "if(\$${loopname}_step == 0)\n\tthrow new \\kch42\\ste\\RuntimeError('step can not be 0 in <ste:for>.');\n";
$code .= "if(\$${loopname}_step > 0)\n{\n";
$code .= "\tfor(\$${loopname}_counter = \$${loopname}_start; \$${loopname}_counter <= \$${loopname}_stop; \$${loopname}_counter += \$${loopname}_step)\n";
$code .= $loopbody;
$code .= "\n}\nelse\n{\n";
$code .= "\tfor(\$${loopname}_counter = \$${loopname}_start; \$${loopname}_counter >= \$${loopname}_stop; \$${loopname}_counter += \$${loopname}_step)\n";
$code .= $loopbody;
$code .= "\n}\n";
} else if($step == 0) {
throw new ParseCompileError("self::Transcompile Error: step can not be 0 in <ste:for>.", $ast->tpl, $ast->offset);
} else if($step > 0) {
$code .= "for(\$${loopname}_counter = \$${loopname}_start; \$${loopname}_counter <= \$${loopname}_stop; \$${loopname}_counter += $step)\n$loopbody\n";
} else {
$code .= "for(\$${loopname}_counter = \$${loopname}_start; \$${loopname}_counter >= \$${loopname}_stop; \$${loopname}_counter += $step)\n$loopbody\n";
}
return $code;
},
"foreach" => function($ast) {
$loopname = self::tempvar("foreachloop");
$code = "";
if(empty($ast->params["array"])) {
throw new ParseCompileError("self::Transcompile Error: array not given in <ste:foreach>.", $ast->tpl, $ast->offset);
}
list($val, $pre) = self::_transcompile($ast->params["array"], true);
$code .= $pre;
$code .= "\$${loopname}_arrayvar = " . $val . ";\n";
if(empty($ast->params["value"])) {
throw new ParseCompileError("self::Transcompile Error: value not given in <ste:foreach>.", $ast->tpl, $ast->offset);
}
list($val, $pre) = self::_transcompile($ast->params["value"], true);
$code .= $pre;
$code .= "\$${loopname}_valuevar = " . $val . ";\n";
if(!empty($ast->params["key"])) {
list($val, $pre) = self::_transcompile($ast->params["key"], true);
$code .= $pre;
$code .= "\$${loopname}_keyvar = " . $val . ";\n";
}
if(!empty($ast->params["counter"])) {
list($val, $pre) = self::_transcompile($ast->params["counter"], true);
$code .= $pre;
$code .= "\$${loopname}_countervar = " . $val . ";\n";
}
$loopbody = "";
$code .= "\$${loopname}_array = \$ste->get_var_by_name(\$${loopname}_arrayvar);\n";
$code .= "if(!is_array(\$${loopname}_array))\n\t\$${loopname}_array = array();\n";
if(!empty($ast->params["counter"])) {
$code .= "\$${loopname}_counter = -1;\n";
$loopbody .= "\$${loopname}_counter++;\n\$ste->set_var_by_name(\$${loopname}_countervar, \$${loopname}_counter);\n";
}
$loop = array();
$else = array();
foreach($ast->sub as $node) {
if(($node instanceof TagNode) && ($node->name == "else")) {
$else = array_merge($else, $node->sub);
} else {
$loop[] = $node;
}
}
$loopbody .= "\$ste->set_var_by_name(\$${loopname}_valuevar, \$${loopname}_value);\n";
if(!empty($ast->params["key"])) {
$loopbody .= "\$ste->set_var_by_name(\$${loopname}_keyvar, \$${loopname}_key);\n";
}
$loopbody .= "\n";
$loopbody .= self::_transcompile($loop);
$loopbody = "{\n" . self::loopbody(self::indent_code($loopbody)) . "\n}\n";
if(!empty($else)) {
$code .= "if(empty(\$${loopname}_array))\n{\n";
$code .= self::indent_code(self::_transcompile($else));
$code .= "\n}\nelse ";
}
$code .= "foreach(\$${loopname}_array as \$${loopname}_key => \$${loopname}_value)\n$loopbody\n";
return $code;
},
"infloop" => function($ast) {
return "while(true)\n{\n" . self::indent_code(self::loopbody(self::indent_code(self::_transcompile($ast->sub)))) . "\n}\n";
},
"break" => function($ast) {
return "throw new \\kch42\\ste\\BreakException();\n";
},
"continue" => function($ast) {
return "throw new \\kch42\\ste\\ContinueException();\n";
},
"block" => function($ast) {
if(empty($ast->params["name"])) {
throw new ParseCompileError("self::Transcompile Error: name missing in <ste:block>.", $ast->tpl, $ast->offset);
}
$blknamevar = self::tempvar("blockname");
list($val, $code) = self::_transcompile($ast->params["name"], true);
$code .= "\$${blknamevar} = " . $val . ";\n";
$tmpblk = uniqid("", true);
$code .= "\$ste->blocks['$tmpblk'] = array_pop(\$outputstack);\n\$ste->blockorder[] = '$tmpblk';\n\$outputstack = array('');\n\$outputstack_i = 0;\n";
$code .= self::_transcompile($ast->sub);
$code .= "\$ste->blocks[\$${blknamevar}] = array_pop(\$outputstack);\n";
$code .= "if(array_search(\$${blknamevar}, \$ste->blockorder) === false)\n\t\$ste->blockorder[] = \$${blknamevar};\n\$outputstack = array('');\n\$outputstack_i = 0;\n";
return $code;
},
"load" => function($ast) {
if(empty($ast->params["name"])) {
throw new ParseCompileError("self::Transcompile Error: name missing in <ste:load>.", $ast->tpl, $ast->offset);
}
list($val, $code) = self::_transcompile($ast->params["name"], true);
$code .= "\$outputstack[\$outputstack_i] .= \$ste->load(" . $val . ");\n";
return $code;
},
"mktag" => function($ast) {
$code = "";
if(empty($ast->params["name"])) {
throw new ParseCompileError("self::Transcompile Error: name missing in <ste:mktag>.", $ast->tpl, $ast->offset);
}
$fxbody = "\$outputstack = array(''); \$outputstack_i = 0;\$ste->vars['_tag_parameters'] = \$params;\n";
list($tagname, $tagname_pre) = self::_transcompile($ast->params["name"], true);
$usemandatory = "";
if(!empty($ast->params["mandatory"])) {
$usemandatory = " use (\$mandatory_params)";
$code .= "\$outputstack[] = '';\n\$outputstack_i++;\n";
$code .= self::_transcompile($ast->params["mandatory"]);
$code .= "\$outputstack_i--;\n\$mandatory_params = explode('|', array_pop(\$outputstack));\n";
$fxbody .= "foreach(\$mandatory_params as \$mp)\n{\n\tif(!isset(\$params[\$mp]))\n\t\tthrow new \\kch42\\ste\\RuntimeError(\"\$mp missing in <ste:\" . $tagname . \">.\");\n}";
}
$fxbody .= self::_transcompile($ast->sub);
$fxbody .= "return array_pop(\$outputstack);";
$code .= "\$tag_fx = function(\$ste, \$params, \$sub)" . $usemandatory . "\n{\n" . self::indent_code($fxbody) . "\n};\n";
$code .= $tagname_pre;
$code .= "\$ste->register_tag($tagname, \$tag_fx);\n";
return $code;
},
"tagcontent" => function($ast) {
return "\$outputstack[\$outputstack_i] .= \$sub(\$ste);";
},
"set" => function($ast) {
if(empty($ast->params["var"])) {
throw new ParseCompileError("self::Transcompile Error: var missing in <ste:set>.", $ast->tpl, $ast->offset);
}
$code = "\$outputstack[] = '';\n\$outputstack_i++;\n";
$code .= self::_transcompile($ast->sub);
$code .= "\$outputstack_i--;\n";
list($val, $pre) = self::_transcompile($ast->params["var"], true);
$code .= $pre;
$code .= "\$ste->set_var_by_name(" . $val . ", array_pop(\$outputstack));\n";
return $code;
},
"get" => function($ast) {
if(empty($ast->params["var"])) {
throw new ParseCompileError("self::Transcompile Error: var missing in <ste:get>.", $ast->tpl, $ast->offset);
}
list($val, $pre) = self::_transcompile($ast->params["var"], true);
$code .= $pre;
return "\$outputstack[\$outputstack_i] .= \$ste->get_var_by_name(" . $val . ");";
},
"calc" => function($ast) {
$code = "\$outputstack[] = '';\n\$outputstack_i++;\n";
$code .= self::_transcompile($ast->sub);
$code .= "\$outputstack_i--;\n\$outputstack[\$outputstack_i] .= \$ste->calc(array_pop(\$outputstack));\n";
return $code;
}
);
}
private static function indent_code($code) {
return implode(
"\n",
array_map(function($line) { return "\t$line"; }, explode("\n", $code))
);
}
private static function loopbody($code) {
return "try\n{\n" . self::indent_code($code) . "\n}\ncatch(\\kch42\\ste\\BreakException \$e) { break; }\ncatch(\\kch42\\ste\\ContinueException \$e) { continue; }\n";
}
private static function _transcompile($ast, $avoid_outputstack = false) { /* The real self::transcompile function, does not add boilerplate code. */
$code = "";
$text_and_var_buffer = array();
foreach($ast as $node) {
if($node instanceof TextNode) {
$text_and_var_buffer[] = '"' . Misc::escape_text($node->text) . '"';
} else if($node instanceof VariableNode) {
$text_and_var_buffer[] = $node->transcompile();
} else if($node instanceof TagNode) {
if(!empty($text_and_var_buffer)) {
$code .= "\$outputstack[\$outputstack_i] .= " . implode (" . ", $text_and_var_buffer) . ";\n";
$text_and_var_buffer = array();
}
if(isset(self::$builtins[$node->name])) {
/* PHP's parser fails once again... Apparently we cannot call a function from an array that is a static property */
$func = self::$builtins[$node->name];
$code .= $func($node);
} else {
$paramarray = self::tempvar("parameters");
$code .= "\$$paramarray = array();\n";
foreach($node->params as $pname => $pcontent) {
list($pval, $pre) = self::_transcompile($pcontent, true);
$code .= $pre . "\$${paramarray}['" . Misc::escape_text($pname) . "'] = " . $pval . ";\n";
}
$code .= "\$outputstack[\$outputstack_i] .= \$ste->call_tag('" . Misc::escape_text($node->name) . "', \$${paramarray}, ";
$code .= empty($node->sub) ? "function(\$ste) { return ''; }" : self::transcompile($node->sub);
$code .= ");\n";
}
}
}
if($avoid_outputstack && ($code == "")) {
return array(implode (" . ", $text_and_var_buffer), "");
}
if(!empty($text_and_var_buffer)) {
$code .= "\$outputstack[\$outputstack_i] .= ". implode (" . ", $text_and_var_buffer) . ";\n";
}
if($avoid_outputstack) {
$tmpvar = self::tempvar("tmp");
$code = "\$outputstack[] = '';\n\$outputstack_i++;" . $code;
$code .= "\$$tmpvar = array_pop(\$outputstack);\n\$outputstack_i--;\n";
return array("\$$tmpvar", $code);
}
return $code;
}
/*
* Function: transcompile
* Transcompiles an abstract syntax tree to PHP.
* You only need this function, if you want to manually transcompile a template.
*
* Parameters:
* $ast - The abstract syntax tree to transcompile.
*
* Returns:
* PHP code. The PHP code is an anonymous function expecting a <STECore> instance as its parameter and returns a string (everything that was not pached into a section).
*/
public static function transcompile($ast) { /* self::Transcompile and add some boilerplate code. */
$boilerplate = "\$outputstack = array('');\n\$outputstack_i = 0;\n";
return "function(\$ste)\n{\n" . self::indent_code($boilerplate . self::_transcompile($ast) . "return array_pop(\$outputstack);") . "\n}";
}
}
Transcompiler::init_builtins();