fix parsing to pass tests

.gitignore

@@ -1,3 +1,4 @@
 vendor
 parsem.sketch
 .DS_Store
+dump.log

composer.json

@@ -8,7 +8,8 @@
     "autoload": {
         "psr-4": {
             "Matronator\\Parsem\\": ["src/Parsem/"]
-        }
+        },
+        "files": ["helpers.php"]
     },
     "authors": [
         {

helpers.php

@@ -0,0 +1,9 @@
+<?php
+
+if (!function_exists('dump')) {
+    function dump($var)
+    {
+        $logFile = __DIR__ . '/dump.log';
+        file_put_contents($logFile, print_r($var, true) . PHP_EOL, FILE_APPEND | LOCK_EX);
+    }
+}

src/Parsem/Parser.php

@@ -25,7 +25,7 @@ final class Parser
      * 3: filter:10,'arg','another'                     --> (filter with args)
      * 4: filter                                        --> (only filter name)
      */
-    public const VARIABLE_PATTERN = '/<%\s?([a-zA-Z0-9_]+)(=.+?)?\|?(([a-zA-Z0-9_]+?)(?:\:(?:(?:\\?\'|\\?")?.?(?:\\?\'|\\?")?,?)+?)*?)?\s?%>/m';
+    public const VARIABLE_PATTERN = '/<%\s?((?!endif|else)[a-zA-Z0-9_]+)(=.+?)?\|?(([a-zA-Z0-9_]+?)(?:\:(?:(?:\\?\'|\\?")?.?(?:\\?\'|\\?")?,?)+?)*?)?\s?%>/m';
 
     /**
      * Matches:
@@ -86,6 +86,61 @@ public static function parseConditions(string $string, array $arguments = [], in
             return $string;
         }
 
+        $result = static::getConditionResult($matches, $arguments);
+
+        $conditionStart = $matches[0][1];
+        $conditionLength = strlen($matches[0][0]);
+
+        $nestedIfs = preg_match_all(static::CONDITION_PATTERN, $string, $nestedMatches, PREG_OFFSET_CAPTURE, $offset + $conditionLength);
+        if ($nestedIfs > 0) {
+            $string = self::parseConditions($string, $arguments, (int)$conditionStart + (int)$conditionLength, $offset);
+        }
+
+        $hasElse = false;
+
+        $elseCount = preg_match('/<%\s?else\s?%>\n?/', $string, $elseMatches, PREG_OFFSET_CAPTURE, $offset);
+        if ($elseCount !== false && $elseCount === 1 && $elseMatches) {
+            $hasElse = true;
+            preg_match('/<%\s?endif\s?%>\n?/', $string, $endMatches, PREG_OFFSET_CAPTURE, $offset);
+            if (!$endMatches) {
+                throw new RuntimeException("Missing <% endif %> tag.");
+            }
+
+            $elseStart = $elseMatches[0][1];
+            $elseTagLength = strlen($elseMatches[0][0]);
+            $conditionEnd = $endMatches[0][1];
+
+            $elseBlock = substr($string, $elseStart + $elseTagLength, $conditionEnd - $elseStart - $elseTagLength);
+        } else if ($elseCount > 1) {
+            throw new RuntimeException("Too many <% else %> tags.");
+        }
+
+        preg_match('/<%\s?endif\s?%>\n?/', $string, $endMatches, PREG_OFFSET_CAPTURE, $offset);
+        if (!$endMatches) {
+            throw new RuntimeException("Missing <% endif %> tag.");
+        }
+
+
+        if ($hasElse) {
+            $conditionEnd = $endMatches[0][1];
+            $insideBlock = substr($string, $conditionStart + $conditionLength, $elseStart - $conditionStart - $conditionLength);
+            $string = substr_replace($string, $result ? $insideBlock : $elseBlock, (int)$conditionStart, $conditionEnd - $conditionStart + strlen($endMatches[0][0]));
+        } else {
+            $conditionEnd = $endMatches[0][1];
+            $insideBlock = substr($string, $conditionStart + $conditionLength, $conditionEnd - $conditionStart - $conditionLength);
+            $string = substr_replace($string, $result ? $insideBlock : '', (int)$conditionStart, $conditionEnd - $conditionStart + strlen($endMatches[0][0]));
+        }
+
+        preg_match(static::CONDITION_PATTERN, $string, $matches, PREG_OFFSET_CAPTURE, $offset);
+        if (!$matches) {
+            return $string;
+        }
+
+        return self::parseConditions($string, $arguments, (int)$conditionStart);
+    }
+
+    public static function getConditionResult(array $matches, array $arguments = []): bool
+    {
         $left = $matches['left'][0];
         $negation = $matches['negation'][0] ?? null;
         $operator = $matches['operator'][0] ?? null;
@@ -182,20 +237,7 @@ public static function parseConditions(string $string, array $arguments = [], in
             $result = $left;
         }
 
-        preg_match('/<%\s?endif\s?%>\n?/', $string, $endMatches, PREG_OFFSET_CAPTURE, $offset);
-        if (!$endMatches) {
-            throw new RuntimeException("Missing <% endif %> tag.");
-        }
-
-        $insideBlock = substr($string, $matches[0][1] + strlen($matches[0][0]), $endMatches[0][1] - $matches[0][1] - strlen($matches[0][0]));
-        $string = substr_replace($string, $result ? $insideBlock : '', (int)$matches[0][1], $endMatches[0][1] - $matches[0][1] + strlen($endMatches[0][0]));
-
-        preg_match(static::CONDITION_PATTERN, $string, $matches, PREG_OFFSET_CAPTURE, $offset);
-        if (!$matches) {
-            return $string;
-        }
-
-        return self::parseConditions($string, $arguments, (int)$matches[0][1]);
+        return $result;
     }
 
     /**

tests/Parsem/ParserTest.php

@@ -192,6 +192,23 @@ public function testNewLines()
         Assert::equal($expected, $parsed, '(false) New lines are ignored.');
         Assert::equal($expected2, $parsed2, '(true) New lines are ignored.');
     }
+
+    /** @testCase */
+    public function testElseBlocks()
+    {
+        $string = "Hello<% if false %> Amazing<% else %> Cruel<% endif %> World!";
+
+        $expected = "Hello Cruel World!";
+
+        $string2 = "Hello<% if true %> Amazing<% else %> Cruel<% endif %> World!";
+
+        $expected2 = "Hello Amazing World!";
+
+        $parsed = Parser::parseString($string, []);
+        $parsed2 = Parser::parseString($string2, []);
+        Assert::equal($expected, $parsed, '(false) Else block is parsed.');
+        Assert::equal($expected2, $parsed2, '(true) If block is parsed.');
+    }
 }
 
 (new ParserTest())->run();

tests/Parsem/output/ParserTest.actual

@@ -1,3 +1,5 @@
 Hello
-
+<% if false %>
+Amazing
+Cruel
 World!

tests/Parsem/output/ParserTest.expected

@@ -1,2 +1,3 @@
 Hello
+Cruel
 World!