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Parse equality string and test equality expression
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<?php | |
// does not consider &&, ||, XOR, OR, AND operator, ternary operators for now. | |
$var_a = 100; | |
$var_b = 100; | |
$var_c = 110; | |
$var_d = (double) 100; | |
$var_e = "100"; | |
$var_f = false; | |
$symbol_table = compact("var_a", "var_b", "var_c", "var_d", "var_e", "var_f"); | |
echo "'\$var_d == \$var_e' is " . (test_eq_expression('$var_d == $var_e', $symbol_table) == true ? "true" : "false").PHP_EOL; | |
echo "'\$var_c != \$var_e' is " . (test_eq_expression('$var_c != $var_e', $symbol_table) == true ? "true" : "false").PHP_EOL; | |
echo "'\$var_b === \$var_e' is " . (test_eq_expression('$var_b === $var_e', $symbol_table) == true ? "true" : "false").PHP_EOL; | |
echo "'\$var_a =< \$var_e' is " . (test_eq_expression('$var_a =< $var_e', $symbol_table) == true ? "true" : "false").PHP_EOL; | |
echo "'\$var_a == \$var_b' is " . (test_eq_expression('$var_a == $var_b', $symbol_table) == true ? "true" : "false").PHP_EOL; | |
echo "'!\$var_f' is " . (test_eq_expression('!$var_f', $symbol_table) == true ? "true" : "false").PHP_EOL; | |
echo "'!\$var_e' is " . (test_eq_expression('!$var_e', $symbol_table) == true ? "true" : "false").PHP_EOL; | |
echo "'\$var_f' is " . (test_eq_expression('$var_f', $symbol_table) == true ? "true" : "false").PHP_EOL; | |
echo "'\$var_e' is " . (test_eq_expression('$var_e', $symbol_table) == true ? "true" : "false").PHP_EOL; | |
function test_eq_expression($expression, $symbol_table = []) { | |
$tokens = token_get_all("<?php $expression ?>"); | |
if(is_array($tokens)) { | |
$fields = []; | |
foreach($tokens as $token) { | |
if(isset($token[1])) { | |
$_ = trim($token[1]); | |
} | |
else if(is_string($token)){ | |
$_ = trim($token); | |
} | |
if(!empty($_) and $_ !== "<?php" and $_ !== "?>") { | |
$fields[] = $_; | |
} | |
} | |
if(count($fields) == 1) { | |
$operator = "unary"; | |
$param1 = str_replace("\$", "", $fields[0]); | |
} | |
else if(count($fields) == 2) { | |
if($fields[0] == "!") { | |
$param1 = str_replace("\$", "", $fields[1]); | |
$operator = $fields[0]; | |
} | |
} | |
else if(count($fields) == 3) { | |
if(in_array($fields[1], ["==", "===", "!=", "!==", "<=", ">=", ">", "<"])) { | |
$param1 = str_replace("\$", "", $fields[0]); | |
$param2 = str_replace("\$", "", $fields[2]); | |
$operator = $fields[1]; | |
} | |
} | |
switch($operator): | |
case "unary": | |
return $symbol_table[$param1] ? true : false; | |
case "!": | |
return !$symbol_table[$param1]; | |
case "==": | |
return $symbol_table[$param1] == $symbol_table[$param2]; | |
break; | |
case "===": | |
return $symbol_table[$param1] === $symbol_table[$param2]; | |
break; | |
case "!=": | |
return $symbol_table[$param1] != $symbol_table[$param2]; | |
break; | |
case "!==": | |
return $symbol_table[$param1] !== $symbol_table[$param2]; | |
break; | |
case "<=": | |
return $symbol_table[$param1] <= $symbol_table[$param2]; | |
break; | |
case ">=": | |
return $symbol_table[$param1] >= $symbol_table[$param2]; | |
break; | |
case ">": | |
return $symbol_table[$param1] > $symbol_table[$param2]; | |
break; | |
case "<": | |
return $symbol_table[$param1] < $symbol_table[$param2]; | |
break; | |
endswitch; | |
} | |
} |
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