File dsl/DslLexer.class.php

Last commit: Tue Jul 19 00:10:39 2022 +0200	Jan Dankert	Fetched from upstream.


     1 <?php
     2 namespace dsl;
     3 
     4 class DslLexer
     5 {
     6 	private $token = [];
     7 
     8 
     9 	const KEYWORDS = [
    10 		'function' => DslToken::T_FUNCTION,
    11 		'for'      => DslToken::T_FOR,
    12 		'if'       => DslToken::T_IF,
    13 		'else'     => DslToken::T_ELSE,
    14 		'let'      => DslToken::T_LET,
    15 		'const'    => DslToken::T_LET,
    16 		'var'      => DslToken::T_LET,
    17 		'return'   => DslToken::T_RETURN,
    18 		'new'      => DslToken::T_NEW,
    19 		'throw'    => DslToken::T_THROW,
    20 		'null'     => DslToken::T_NULL,
    21 		'true'     => DslToken::T_TRUE,
    22 		'false'    => DslToken::T_FALSE,
    23 	];
    24 
    25 	const IGNORED_KEYWORDS = [
    26 		'let',
    27 		'new',
    28 	];
    29 
    30 	const UNUSED_KEYWORDS = [
    31 		'implements',
    32 		'interface',
    33 		'package',
    34 		'private',
    35 		'protected',
    36 		'public',
    37 		'static',
    38 		'in',
    39 		'do',
    40 		'try',
    41 		'catch',
    42 		'finally',
    43 		'this',
    44 		'case',
    45 		'void',
    46 		'with',
    47 		'enum',
    48 		'while',
    49 		'break',
    50 		'yield',
    51 		'class',
    52 		'super',
    53 		'typeof',
    54 		'delete',
    55 		'switch',
    56 		'export',
    57 		'import',
    58 		'default',
    59 		'extends',
    60 		'continue',
    61 		'debugger',
    62 		'instanceof',
    63 		'goto', // ;)
    64 		];
    65 	/**
    66 	 * @param $code
    67 	 * @return array(DslToken)
    68 	 */
    69 	public function tokenize( $code ) {
    70 
    71 		//echo "Code: <pre>".$code."</pre>";
    72 
    73 		$line = 1;
    74 
    75 		// mb_str_split only available since PHP 7.4
    76 		$chars = str_split($code);
    77 
    78 		while( true ) {
    79 			$char = array_shift($chars);
    80 
    81 			if   ( $char == null )
    82 				break;
    83 
    84 			if   ( ( $char == ' ' ))
    85 				continue;
    86 
    87 			if   ( ( $char == "\n" )) {
    88 				$line++;
    89 				continue;
    90 			}
    91 
    92 			// Text
    93 			if   ( $char == '"' || $char == "'" ) {
    94 				$textEncloser = $char;
    95 				$value = '';
    96 				while( true ) {
    97 					$char = array_shift($chars);
    98 					if   ( $char == "\n")
    99 						throw new DslParserException("Unclosed string",$line);
   100 					if   ( $char == '\\') {
   101 						$char = array_shift($chars);
   102 						if   ( $char == 'n' )
   103 							$value = "\n";
   104 						elseif ( $char == 't' )
   105 							$value = "\t";
   106 						else
   107 							$value .= $char;
   108 					}
   109 					elseif ($char != $textEncloser) {
   110 						$value .= $char;
   111 						continue;
   112 					} else {
   113 						$this->addToken($line, DslToken::T_TEXT, $value);
   114 						break;
   115 					}
   116 				}
   117 				continue;
   118 			}
   119 
   120 			// Comments
   121 			if   ( $char == '/' ) {
   122 				$nextChar = array_shift($chars);
   123 				if   ( $nextChar == '/' ) { // Comment after "//"
   124 
   125 					while( true ) {
   126 						$c = array_shift($chars);
   127 						if ($c == "\n")
   128 							$line++;
   129 						if ($c == "\n" || $c == null )
   130 							continue 2;
   131 					}
   132 
   133 				}
   134 				elseif   ( $nextChar == '*' ) { // Comment after "/*"
   135 
   136 					$lastChar = null;
   137 					while( true ) {
   138 						$c = array_shift($chars);
   139 						if   ( $c == null )
   140 							break 2;
   141 						if ($c == "\n")
   142 							$line++;
   143 						if   ( $lastChar == '*' && $c == '/')
   144 							continue 2;
   145 						$lastChar = $c;
   146 						continue;
   147 					}
   148 
   149 				}
   150 				else {
   151 					array_unshift($chars,$nextChar); // this is no comment
   152 				}
   153 			}
   154 
   155 			// String
   156 			if   ( ( $char >= 'a' && $char <= 'z') ||
   157 				   ( $char >= 'A' && $char <= 'Z') ||
   158 				   $char == '_'                    ||
   159 				   $char == '$' ) {
   160 				$value = $char;
   161 				while( true ) {
   162 					$char = array_shift( $chars );
   163 					if   ( ( $char >= 'a' && $char <= 'z') ||
   164 						( $char >= 'A' && $char <= 'Z') ||
   165 						( $char >= '0' && $char <= '9') ||
   166 						$char == '_'                    ||
   167 						$char == '$' ) {
   168 						$value .= $char;
   169 					} else {
   170 						$type = DslToken::T_STRING;
   171 
   172 						if   ( array_search($value,self::UNUSED_KEYWORDS ) !== false )
   173 							throw new DslParserException( 'use of reserved word \''.$value.'\' is not allowed.');
   174 
   175 						if   ( array_search($value,self::IGNORED_KEYWORDS ) !== false )
   176 							break; // ignore this keyword
   177 
   178 						if   ( array_key_exists($value,self::KEYWORDS ) )
   179 							$type = self::KEYWORDS[$value]; // it is a keyword
   180 
   181 						$this->addToken( $line,$type,$value );
   182 						array_unshift($chars,$char);
   183 						break;
   184 					}
   185 				}
   186 				continue;
   187 			}
   188 
   189 			// Numbers
   190 			// TODO we have a problem with
   191 			// - "-" is an operator, so we cannot parse negative numbers
   192 			// - "." is the property char, so we cannot parse decimal values
   193 			if   ( $char >= '0' && $char <= '9' ) {
   194 				$value = $char;
   195 				while( true ) {
   196 					$char = array_shift( $chars );
   197 					if   ( ( $char >= '0' && $char <= '9') ||
   198 						$char == '_' ) {
   199 						$value .= $char;
   200 					} else {
   201 						$this->addToken( $line,DslToken::T_NUMBER,str_replace('_','',$value ));
   202 						array_unshift($chars,$char);
   203 						break;
   204 					}
   205 				}
   206 				continue;
   207 			}
   208 
   209 			$operatorChars = ['>','<','+' ,'-','/' ,'*','=','|','&',',','.' ];
   210 			if   ( in_array($char,$operatorChars)) {
   211 
   212 				$value = $char;
   213 				while( true ) {
   214 					$char = array_shift( $chars );
   215 					if   ( in_array($char,$operatorChars) ) {
   216 						$value .= $char;
   217 					} else {
   218 						$type = DslToken::T_OPERATOR;
   219 						$this->addToken( $line,$type,$value );
   220 						array_unshift($chars,$char);
   221 						continue 2;
   222 					}
   223 				}
   224 				continue;
   225 			}
   226 
   227 			if   ( $char == "\r" )
   228 				continue;
   229 			elseif   ( $char == '!' )
   230 				$this->addToken( $line,DslToken::T_NEGATION,$char);
   231 			elseif   ( $char == ';' )
   232 				$this->addToken( $line,DslToken::T_STATEMENT_END,$char);
   233 			elseif   ( $char == '.' )
   234 				$this->addToken( $line,DslToken::T_DOT,$char);
   235 			elseif   ( $char == ',' )
   236 				$this->addToken( $line,DslToken::T_COMMA,$char);
   237 
   238 			elseif   ( $char == '(' ) {
   239 				if  ( end( $this->token)->type == DslToken::T_STRING)
   240 					// if string is followed by "(" it is a function or a function call
   241 					$this->addToken( $line, DslToken::T_OPERATOR,'$'); // function call
   242 				$this->addToken( $line,DslToken::T_BRACKET_OPEN,$char);
   243 			}
   244 			elseif   ( $char == ')' ) {
   245 				if (end($this->token)->type == DslToken::T_BRACKET_OPEN)
   246 					// if there is an empty parenthesis, make it contain something, otherwise the shunting yard algo will fail.
   247 					$this->addToken($line, DslToken::T_NONE ); //
   248 				$this->addToken($line, DslToken::T_BRACKET_CLOSE, $char);
   249 			}
   250 			elseif   ( $char == '{' )
   251 				$this->addToken( $line,DslToken::T_BLOCK_BEGIN,$char);
   252 			elseif   ( $char == '}' )
   253 				$this->addToken( $line,DslToken::T_BLOCK_END,$char);
   254 			else {
   255 				throw new DslParserException('Unknown character \''.$char.'\'',$line);
   256 			}
   257 		}
   258 
   259 
   260 		return $this->token;
   261 	}
   262 
   263 	private function addToken(int $line, $type, $value=null)
   264 	{
   265 		$this->token[] = new DslToken( $line, $type, $value );
   266 	}
   267 
   268 
   269 }



Download dsl/DslLexer.class.php


History
Tue, 19 Jul 2022 00:10:39 +0200	Jan Dankert	Fetched from upstream.
Sun, 26 Jun 2022 16:04:19 +0200	Jan Dankert	Fetched from upstream; More examples.
Sun, 26 Jun 2022 15:47:05 +0200	Jan Dankert	Fetched from upstream.
Tue, 7 Jun 2022 23:33:20 +0200	Jan Dankert	Fetched from upstream: support for "throw".
Mon, 6 Jun 2022 14:06:46 +0200	Jan Dankert	First commit after fetching from upstream repo.