removed fn in front of arrow functions

doc/filters/filter.rst

@@ -11,7 +11,7 @@ function. The arrow function receives the value of the sequence or mapping:
 
     {% set sizes = [34, 36, 38, 40, 42] %}
 
-    {% for v in sizes|filter(|v| => v > 38) -%}
+    {% for v in sizes|filter(v => v > 38) -%}
         {{ v }}
     {% endfor %}
     {# output 40 42 #}
@@ -24,7 +24,7 @@ function. The arrow function receives the value of the sequence or mapping:
         xl: 42,
     } %}
 
-    {% for k, v in sizes|filter(|v| => v > 38) -%}
+    {% for k, v in sizes|filter(v => v > 38) -%}
         {{ k }} = {{ v }}
     {% endfor %}
     {# output l = 40 xl = 42 #}

doc/filters/map.rst

@@ -14,7 +14,7 @@ mapping. The arrow function receives the value of the sequence or mapping:
         {first: "Alice", last: "Dupond"},
     ] %}
 
-    {{ people|map(|p| => "#{p.first} #{p.last}")|join(', ') }}
+    {{ people|map(p => "#{p.first} #{p.last}")|join(', ') }}
     {# outputs Bob Smith, Alice Dupond #}
 
 Note that the arrow function has access to the current context.

doc/filters/reduce.rst

@@ -13,14 +13,14 @@ value of the sequence or mapping:
 
     {% set numbers = [1, 2, 3] %}
 
-    {{ numbers|reduce(|carry, v| => carry + v) }}
+    {{ numbers|reduce((carry, v) => carry + v) }}
     {# output 6 #}
 
 The ``reduce`` filter takes an ``initial`` value as a second argument:
 
 .. code-block:: twig
 
-    {{ numbers|reduce(|carry, v| => carry + v, 10) }}
+    {{ numbers|reduce((carry, v) => carry + v, 10) }}
     {# output 16 #}
 
 Note that the arrow function has access to the current context.

src/ExpressionParser.php

@@ -109,22 +109,47 @@ class ExpressionParser
     private function parseArrow()
     {
         $stream = $this->parser->getStream();
-        $token = $this->parser->getCurrentToken();
-        $line = $token->getLine();
-        if (!$token->test(Token::NAME_TYPE, 'fn')) {
+
+        // short array syntax (one argument, no parentheses)?
+        if ($stream->look(1)->test(Token::ARROW_TYPE)) {
+            $line = $stream->getCurrent()->getLine();
+            $token = $stream->expect(Token::NAME_TYPE);
+            $names = [new AssignNameExpression($token->getValue(), $token->getLine())];
+            $stream->expect(Token::ARROW_TYPE);
+
+            return new ArrowFunctionExpression($this->parseExpression(0), new Node($names), $line);
+        }
+
+        // first, determine if we are parsing an arrow function by finding => (long form)
+        $i = 0;
+        if (!$stream->look($i)->test(Token::PUNCTUATION_TYPE, '(')) {
             return null;
         }
-        if ($stream->look(2)->test(Token::PUNCTUATION_TYPE, '(')) {
+        ++$i;
+        while (true) {
+            // variable name
+            ++$i;
+            if (!$stream->look($i)->test(Token::PUNCTUATION_TYPE, ',')) {
+                break;
+            }
+            ++$i;
+        }
+        if (!$stream->look($i)->test(Token::PUNCTUATION_TYPE, ')')) {
+            return null;
+        }
+        ++$i;
+        if (!$stream->look($i)->test(Token::ARROW_TYPE)) {
             return null;
         }
 
-        $stream->next(); // fn
-        $stream->next(); // (
+        // yes, let's parse it properly
+        $token = $stream->expect(Token::PUNCTUATION_TYPE, '(');
+        $line = $token->getLine();
+
         $names = [];
         while (true) {
             $token = $stream->expect(Token::NAME_TYPE);
-            $value = $token->getValue();
-            $names[] = new AssignNameExpression($value, $token->getLine());
+            $names[] = new AssignNameExpression($token->getValue(), $token->getLine());
 
             if (!$stream->nextIf(Token::PUNCTUATION_TYPE, ',')) {
                 break;

test/Twig/Tests/Fixtures/expressions/not_arrow_fn.test

@@ -0,0 +1,8 @@
+--TEST--
+A string in parentheses cannot be confused with an arrow function
+--TEMPLATE--
+{{ ["foo", "bar"]|join(("f")) }}
+--DATA--
+return []
+--EXPECT--
+foofbar

test/Twig/Tests/Fixtures/filters/filter.test

@@ -3,10 +3,15 @@
 --TEMPLATE--
 {% set offset = 3 %}
 
-{% for k, v in [1, 5, 3, 4, 5]|filter(fn(v) => v > offset) -%}
+{% for k, v in [1, 5, 3, 4, 5]|filter((v) => v > offset) -%}
     {{ k }} = {{ v }}
 {% endfor %}
-{% for k, v in {a: 1, b: 2, c: 5, d: 2}|filter(fn(v) => v > offset) -%}
+
+{% for k, v in {a: 1, b: 2, c: 5, d: 2}|filter((v) => v > offset) -%}
+    {{ k }} = {{ v }}
+{% endfor %}
+
+{% for k, v in [1, 5, 3, 4, 5]|filter(v => v > offset) -%}
     {{ k }} = {{ v }}
 {% endfor %}
 --DATA--
@@ -15,4 +20,9 @@ return []
 1 = 5
 3 = 4
 4 = 5
+
 c = 5
+
+1 = 5
+3 = 4
+4 = 5

test/Twig/Tests/Fixtures/filters/map.test

@@ -3,10 +3,15 @@
 --TEMPLATE--
 {% set offset = 3 %}
 
-{% for k, v in [1, 2]|map(fn(item) => item + 2 ) -%}
+{% for k, v in [1, 2]|map((item) => item + 2 ) -%}
     {{ k }} = {{ v }}
 {% endfor %}
-{% for k, v in {a: 1, b: 2}|map(fn(item) => item ~ "*" ) -%}
+
+{% for k, v in {a: 1, b: 2}|map((item) => item ~ "*" ) -%}
+    {{ k }} = {{ v }}
+{% endfor %}
+
+{% for k, v in [1, 2]|map(item => item + 2 ) -%}
     {{ k }} = {{ v }}
 {% endfor %}
 --DATA--
@@ -14,5 +19,9 @@ return []
 --EXPECT--
 0 = 3
 1 = 4
+
 a = 1*
 b = 2*
+
+0 = 3
+1 = 4

test/Twig/Tests/Fixtures/filters/reduce.test

@@ -3,7 +3,7 @@
 --TEMPLATE--
 {% set offset = 3 %}
 
-{{ [1, -1, 4]|reduce(fn(carry, item) => carry + item + offset, 10) }}
+{{ [1, -1, 4]|reduce((carry, item) => carry + item + offset, 10) }}
 --DATA--
 return []
 --EXPECT--