File modules/dsl/ast/DslElement.class.php

Last commit: Wed Jun 1 00:11:40 2022 +0200	Jan Dankert	New: DSL as a filter for number values


     1 <?php
     2 
     3 namespace dsl\ast;
     4 
     5 use dsl\DslParserException;
     6 use dsl\DslToken;
     7 
     8 class DslElement
     9 {
    10 
    11 	/**
    12 	 *
    13 	 * @param $tokens DslToken[]
    14 	 * @return DslToken[]
    15 	 * @throws DslParserException
    16 	 */
    17 	protected function getGroup(&$tokens)
    18 	{
    19 		$groupTokens = [];
    20 		$depth = 0;
    21 
    22 		$nextToken = array_shift($tokens);
    23 		if ($nextToken == null)
    24 			throw new DslParserException('Unexpecting end, missing closing group');
    25 		if ($nextToken->type != DslToken::T_BRACKET_OPEN)
    26 			throw new DslParserException('Expecting parenthesis', $nextToken->lineNumber);
    27 
    28 		while (true) {
    29 			$nextToken = array_shift($tokens);
    30 			if ($nextToken == null)
    31 				throw new DslParserException('Unclosed parenthesis');
    32 			if ($nextToken->type == DslToken::T_BRACKET_OPEN)
    33 				$depth += 1;
    34 			if ($nextToken->type == DslToken::T_BRACKET_CLOSE)
    35 				if ($depth == 0)
    36 					return $groupTokens;
    37 				else
    38 					$depth--;
    39 
    40 			$groupTokens[] = $nextToken;
    41 		}
    42 	}
    43 
    44 	/**
    45 	 *
    46 	 * @param $tokens DslToken[]
    47 	 * @return DslToken[]
    48 	 * @throws DslParserException
    49 	 */
    50 	protected function getBlock(&$tokens)
    51 	{
    52 		$blockTokens = [];
    53 		$depth = 0;
    54 
    55 		$nextToken = array_shift($tokens);
    56 		if ($nextToken->type != DslToken::T_BLOCK_BEGIN)
    57 			throw new DslParserException('Expecting block', $nextToken->lineNumber);
    58 
    59 		while (true) {
    60 			$nextToken = array_shift($tokens);
    61 			if ($nextToken->type == null)
    62 				throw new DslParserException('Unclosed block', $nextToken->lineNumber);
    63 			if ($nextToken->type == DslToken::T_BLOCK_BEGIN)
    64 				$depth += 1;
    65 			if ($nextToken->type == DslToken::T_BLOCK_END)
    66 				if ($depth == 0)
    67 					return $blockTokens;
    68 				else
    69 					$depth--;
    70 
    71 			$blockTokens[] = $nextToken;
    72 		}
    73 	}
    74 
    75 	/**
    76 	 *
    77 	 * @param $tokens DslToken[]
    78 	 * @return DslToken[]
    79 	 * @throws DslParserException
    80 	 */
    81 	protected function getStatementOrBlock(&$tokens)
    82 	{
    83 		if (!$tokens)
    84 			return [];
    85 
    86 		$firstToken = $tokens[0];
    87 		if ($firstToken->type == DslToken::T_BLOCK_BEGIN)
    88 			return $this->getBlock($tokens);
    89 		else
    90 			return $this->getSingleStatement($tokens,true);
    91 	}
    92 
    93 
    94 	/**
    95 	 * Gets the first single statement out of the tokens.
    96 	 *
    97 	 * @param $tokens DslToken[]
    98 	 * @return DslToken[]
    99 	 * @throws DslParserException
   100 	 */
   101 	protected function getSingleStatement(&$tokens, $withEnd = false)
   102 	{
   103 		$depth = 0;
   104 		$statementTokens = [];
   105 		while (true) {
   106 			$nextToken = array_shift($tokens);
   107 			if ($nextToken == null)
   108 				var_export( $statementTokens );
   109 			if ($nextToken == null)
   110 				throw new DslParserException('unrecognized statement');
   111 
   112 			if ($depth == 0 && $nextToken->type == DslToken::T_STATEMENT_END) {
   113 				if   ( $withEnd )
   114 					$statementTokens[] = $nextToken;
   115 				return $statementTokens;
   116 			}
   117 
   118 			if ($nextToken->type == DslToken::T_BLOCK_BEGIN)
   119 				$depth++;
   120 			if ($nextToken->type == DslToken::T_BLOCK_END)
   121 				$depth--;
   122 			if ($depth < 0)
   123 				throw new DslParserException('Unexpected closing block', $nextToken->lineNumber);
   124 
   125 			$statementTokens[] = $nextToken;
   126 		}
   127 	}
   128 
   129 
   130 	/**
   131 	 * Split tokens on comma separator.
   132 	 *
   133 	 * @param DslToken[] $functionParameter
   134 	 * @return DslToken[][]
   135 	 */
   136 	protected function splitByComma($functionParameter)
   137 	{
   138 		$parts = [];
   139 		$act   = [];
   140 		foreach ( $functionParameter as $token ) {
   141 
   142 			if   ( $token->type == DslToken::T_OPERATOR && $token->value == ',' ) {
   143 				$parts[] = $act;
   144 				$act     = []; // Cleanup
   145 				continue;
   146 			}
   147 
   148 			$act[] = $token;
   149 		}
   150 
   151 		if   ( $act )
   152 			$parts[] = $act;
   153 
   154 		return $parts;
   155 	}
   156 }



Download modules/dsl/ast/DslElement.class.php


History
Wed, 1 Jun 2022 00:11:40 +0200	Jan Dankert	New: DSL as a filter for number values
Sun, 29 May 2022 16:56:40 +0200	Jan Dankert	New: DSL with support for functions with return values, full arithmetic, object properties
Sun, 29 May 2022 01:13:27 +0200	Jan Dankert	New: DSL with support for functions
Wed, 25 May 2022 22:47:17 +0200	Jan Dankert	New: DSL (domain specific language) for code elements. The old way with PHP code ist not sandboxed and unsecure. This approach is a minimalistic, javascript-like, scripting engine. For now only simple function calls are possible, for example: alert("example");