diff options
Diffstat (limited to 'Parser.php')
| -rw-r--r-- | Parser.php | 451 |
1 files changed, 451 insertions, 0 deletions
diff --git a/Parser.php b/Parser.php new file mode 100644 index 0000000..1ca0798 --- /dev/null +++ b/Parser.php @@ -0,0 +1,451 @@ +<?php + +namespace kch42\ste; + +/* + * Class: Parser + * The class, where the parser lives in. Can not be constructed manually. + * Use the static method parse. + */ +class Parser { + private $text; + private $name; + private $off; + private $len; + + const PARSE_SHORT = 1; + const PARSE_TAG = 2; + + const ESCAPES_DEFAULT = '$?~{}|\\'; + + private function __construct($text, $name) { + $this->text = $text; + $this->name = $name; + $this->off = 0; + $this->len = mb_strlen($text); + } + + private function next($n = 1) { + if($n <= 0) { + throw new \InvalidArgumentException("\$n must be > 0"); + } + $c = mb_substr($this->text, $this->off, $n); + $this->off = min($this->off + $n, $this->len); + return $c; + } + + + private function back($n = 1) { + if($n <= 0) { + throw new \InvalidArgumentException("\$n must be > 0"); + } + $this->off = max($this->off - $n, 0); + } + + private function search_off($needle) { + return mb_strpos($this->text, $needle, $this->off); + } + + private function search_multi($needles) { + $oldoff = $this->off; + + $minoff = $this->len; + $which = NULL; + + foreach($needles as $key => $needle) { + if(($off = $this->search_off($needle)) === false) { + continue; + } + + if($off < $minoff) { + $minoff = $off; + $which = $key; + } + } + + $this->off = $minoff + (($which === NULL) ? 0 : mb_strlen((string) $needles[$which])); + + return array($which, $minoff, mb_substr($this->text, $oldoff, $minoff - $oldoff), $oldoff); + } + + private function search($needle) { + $oldoff = $this->off; + + $off = $this->search_off($needle); + if($off === false) { + $this->off = $this->len; + return array(false, mb_substr($this->text, $oldoff), $oldoff); + } + + $this->off = $off + mb_strlen($needle); + return array($off, mb_substr($this->text, $oldoff, $off - $oldoff), $oldoff); + } + + private function take_while($cb) { + $s = ""; + while($c = $this->next()) { + if(!call_user_func($cb, $c)) { + $this->back(); + return $s; + } + $s .= $c; + } + return $s; + } + + private function skip_ws() { + $this->take_while("ctype_space"); + } + + private function get_name() { + $off = $this->off; + $name = $this->take_while(function($c) { return ctype_alnum($c) || ($c == "_"); }); + if(mb_strlen($name) == 0) { + throw new ParseCompileError("Expected a name (alphanumeric chars + '_', at least one char)", $this->name, $off); + } + return $name; + } + + /* + * Function: parse + * Parses the input into an AST. + * + * You only need this function, if you want to manually trnascompile a template. + * + * Parameters: + * $text - The input code. + * $name - The name of the template. + * + * Returns: + * An array of <ASTNode> objects. + * + * Throws: + * <ParseCompileError> + */ + public static function parse($text, $name) { + $obj = new self($text, $name); + $res = $obj->parse_text( + self::ESCAPES_DEFAULT, /* Escapes */ + self::PARSE_SHORT | self::PARSE_TAG /* Flags */ + ); + return self::tidyup_ast($res[0]); + } + + private static function tidyup_ast($ast) { + $out = array(); + + $prevtext = NULL; + $first = true; + + foreach($ast as $node) { + if($node instanceof TextNode) { + if($prevtext === NULL) { + $prevtext = $node; + } else { + $prevtext->text .= $node->text; + } + } else { + if($prevtext !== NULL) { + if($first) { + $prevtext->text = ltrim($prevtext->text); + } + if($prevtext->text != "") { + $out[] = $prevtext; + } + } + $prevtext = NULL; + $first = false; + + if($node instanceof TagNode) { + $node->sub = self::tidyup_ast($node->sub); + foreach($node->params as $k => &$v) { + $v = self::tidyup_ast($v); + } + unset($v); + } else { /* VariableNode */ + foreach($node->arrayfields as &$v) { + $v = self::tidyup_ast($v); + } + unset($v); + } + + $out[] = $node; + } + } + + if($prevtext !== NULL) { + if($first) { + $prevtext->text = ltrim($prevtext->text); + } + if($prevtext->text != "") { + $out[] = $prevtext; + } + } + + return $out; + } + + private function parse_text($escapes, $flags, $breakon = NULL, $separator = NULL, $nullaction = NULL, $opentag = NULL, $openedat = -1) { + $elems = array(); + $astlist = array(); + + $needles = array( + "commentopen" => "<ste:comment>", + "rawopen" => "<ste:rawtext>", + "escape" => '\\', + "varcurlyopen" => '${', + "var" => '$', + ); + + if($flags & self::PARSE_TAG) { + $needles["tagopen"] = '<ste:'; + $needles["closetagopen"] = '</ste:'; + } + if($flags & self::PARSE_SHORT) { + $needles["shortifopen"] = '?{'; + $needles["shortcompopen"] = '~{'; + } + + if($separator !== NULL) { + $needles["sep"] = $separator; + } + if($breakon !== NULL) { + $needles["break"] = $breakon; + } + + for(;;) { + list($which, $off, $before, $offbefore) = $this->search_multi($needles); + + $astlist[] = new TextNode($this->name, $offbefore, $before); + + switch($which) { + case NULL: + if($nullaction === NULL) { + $elems[] = $astlist; + return $elems; + } else { + call_user_func($nullaction); + } + break; + case "commentopen": + list($off, $before, $offbefore) = $this->search("</ste:comment>"); + if($off === false) { + throw new ParseCompileError("ste:comment was not closed", $this->name, $offbefore); + } + break; + case "rawopen": + $off_start = $off; + list($off, $before, $offbefore) = $this->search("</ste:rawtext>"); + if($off === false) { + throw new ParseCompileError("ste:rawtext was not closed", $this->name, $off_start); + } + $astlist[] = new TextNode($this->name, $off_start, $before); + break; + case "tagopen": + $astlist[] = $this->parse_tag($off); + break; + case "closetagopen": + $off_start = $off; + $name = $this->get_name(); + $this->skip_ws(); + $off = $this->off; + if($this->next() != ">") { + throw new ParseCompileError("Expected '>' in closing ste-Tag", $this->name, $off); + } + + if($opentag === NULL) { + throw new ParseCompileError("Found closing ste:$name tag, but no tag was opened", $this->name, $off_start); + } + if($opentag != $name) { + throw new ParseCompileError("Open ste:$opentag was not closed", $this->name, $openedat); + } + + $elems[] = $astlist; + return $elems; + case "escape": + $c = $this->next(); + if(mb_strpos($escapes, $c) !== false) { + $astlist[] = new TextNode($this->name, $off, $c); + } else { + $astlist[] = new TextNode($this->name, $off, '\\'); + $this->back(); + } + break; + case "shortifopen": + $shortelems = $this->parse_short("?{", $off); + if(count($shortelems) != 3) { + throw new ParseCompileError("A short if tag must have the form ?{..|..|..}", $this->name, $off); + } + + list($cond, $then, $else) = $shortelems; + $thentag = new TagNode($this->name, $off); + $thentag->name = "then"; + $thentag->sub = $then; + + $elsetag = new TagNode($this->name, $off); + $elsetag->name = "else"; + $elsetag->sub = $else; + + $iftag = new TagNode($this->name, $off); + $iftag->name = "if"; + $iftag->sub = $cond; + $iftag->sub[] = $thentag; + $iftag->sub[] = $elsetag; + + $astlist[] = $iftag; + break; + case "shortcompopen": + $shortelems = $this->parse_short("~{", $off); + if(count($shortelems) != 3) { + throw new ParseCompileError("A short comparasion tag must have the form ~{..|..|..}", $this->name, $off); + } + + // TODO: What will happen, if a tag was in one of the elements? + list($a, $op, $b) = $shortelems; + $cmptag = new TagNode($this->name, $off); + $cmptag->name = "cmp"; + $cmptag->params["text_a"] = $a; + $cmptag->params["op"] = $op; + $cmptag->params["text_b"] = $b; + + $astlist[] = $cmptag; + break; + case "sep": + $elems[] = $astlist; + $astlist = array(); + break; + case "varcurlyopen": + $astlist[] = $this->parse_var($off, true); + break; + case "var": + $astlist[] = $this->parse_var($off, false); + break; + case "break": + $elems[] = $astlist; + return $elems; + } + } + + $elems[] = $astlist; + return $elems; + } + + private function parse_short($shortname, $openedat) { + $tplname = $this->name; + + return $this->parse_text( + self::ESCAPES_DEFAULT, /* Escapes */ + self::PARSE_SHORT | self::PARSE_TAG, /* Flags */ + '}', /* Break on */ + '|', /* Separator */ + function() use ($shortname, $tplname, $openedat) { /* NULL action */ + throw new ParseCompileError("Unclosed $shortname", $tplname, $openedat); + }, + NULL, /* Open tag */ + $openedat /* Opened at */ + ); + } + + private function parse_var($openedat, $curly) { + $varnode = new VariableNode($this->name, $openedat); + $varnode->name = $this->get_name(); + $varnode->arrayfields = $this->parse_array(); + + if(($curly) && ($this->next() != "}")) { + throw new ParseCompileError("Unclosed '\${'", $this->name, $openedat); + } + return $varnode; + } + + private function parse_array() { + $tplname = $this->name; + + $arrayfields = array(); + + while($this->next() == "[") { + $openedat = $this->off - 1; + $res = $this->parse_text( + self::ESCAPES_DEFAULT, /* Escapes */ + 0, /* Flags */ + ']', /* Break on */ + NULL, /* Separator */ + function() use ($tplname, $openedat) { /* NULL action */ + throw new ParseCompileError("Unclosed array access '[...]'", $tplname, $openedat); + }, + NULL, /* Open tag */ + $openedat /* Opened at */ + ); + $arrayfields[] = $res[0]; + } + + $this->back(); + return $arrayfields; + } + + private function parse_tag($openedat) { + $tplname = $this->name; + + $this->skip_ws(); + $tag = new TagNode($this->name, $openedat); + $name = $tag->name = $this->get_name(); + $tag->params = array(); + $tag->sub = array(); + + for(;;) { + $this->skip_ws(); + + switch($this->next()) { + case '/': /* Self-closing tag */ + $this->skip_ws(); + if($this->next() != '>') { + throw new ParseCompileError("Unclosed opening <ste: tag (expected >)", $this->name, $openedat); + } + + return $tag; + case '>': + $sub = $this->parse_text( + self::ESCAPES_DEFAULT, /* Escapes */ + self::PARSE_SHORT | self::PARSE_TAG, /* Flags */ + NULL, /* Break on */ + NULL, /* Separator */ + function() use ($name, $tplname, $openedat) { /* NULL action */ + throw new ParseCompileError("Open ste:$name tag was not closed", $tplname, $openedat); + }, + $tag->name, /* Open tag */ + $openedat /* Opened at */ + ); + $tag->sub = $sub[0]; + return $tag; + default: + $this->back(); + + $param = $this->get_name(); + + $this->skip_ws(); + if($this->next() != '=') { + throw new ParseCompileError("Expected '=' after tag parameter name", $this->name, $this->off - 1); + } + $this->skip_ws(); + + $quot = $this->next(); + if(($quot != '"') && ($quot != "'")) { + throw new ParseCompileError("Expected ' or \" after '=' of tag parameter", $this->name, $this->off - 1); + } + + $off = $this->off - 1; + $paramval = $this->parse_text( + self::ESCAPES_DEFAULT . $quot, /* Escapes */ + 0, /* Flags */ + $quot, /* Break on */ + NULL, /* Separator */ + function() use ($quot, $tplname, $off) { /* NULL action */ + throw new ParseCompileError("Open tag parameter value ($quot) was not closed", $tplname, $off); + }, + NULL, /* Open tag */ + $off /* Opened at */ + ); + $tag->params[$param] = $paramval[0]; + } + } + } +} |