fix for and add reversed argument

CLAUDE.md

@@ -242,6 +242,10 @@ documentation or memory. Both checks are worth repeating whenever tags, filters
   `{% cache 500 sidebar.name %}` names a fragment there, `{% cache 500 using="c" %}` names a fragment
   called `using="c"` rather than choosing a cache, and `{% cache 500 sidebar using= %}` takes an empty
   name. All three are errors here.
+- `do_for` reads `reversed` off the end of the tag before it looks for `in`, so `{% for x in reversed %}`
+  is an error there and a loop over a variable named `reversed` here. Writing the flag as well
+  (`{% for x in reversed reversed %}`) is accepted by both, which is why the name is not simply reserved
+  in that position.
 - `do_translate` refuses `as` and `noop` as the value of its `context` option, so
   `{% trans "hi" context noop %}` is an error there and a context named by the variable `noop` here.
 - `partial`/`partialdef` are Django builtins as of Django 6; `elif`/`else`/`empty` are modelled as parts of

grammar.js

@@ -291,6 +291,7 @@ const django = grammar({
   // after it settles
   conflicts: ($) => [
     [$.template],
+    [$.for_scope],
     [$.predicate],
     [$.library, $.load],
     [$._translate_option],
@@ -621,7 +622,6 @@ const django = grammar({
         optional(asVariable($)),
       ),
     for_scope: ($) =>
-      prec.left(
       seq(
         block(
           "for",
@@ -636,10 +636,12 @@ const django = grammar({
           ),
           part("in"),
           part($.filtered_value),
+          // do_for reads this off the end and takes the sequence from the bit
+          // before it, so it comes last or not at all
+          optional(part("reversed")),
         ),
         optional($.template),
       ),
-      ),
     for_group: ($) =>
       seq(
         $.for_scope,

src/grammar.json

@@ -3262,9 +3262,6 @@
       ]
     },
     "for_scope": {
-      "type": "PREC_LEFT",
-      "value": 0,
-      "content": {
       "type": "SEQ",
       "members": [
         {
@@ -3381,6 +3378,27 @@
                 }
               ]
             },
+            {
+              "type": "CHOICE",
+              "members": [
+                {
+                  "type": "SEQ",
+                  "members": [
+                    {
+                      "type": "PATTERN",
+                      "value": "[ \\t\\r\\n]+"
+                    },
+                    {
+                      "type": "STRING",
+                      "value": "reversed"
+                    }
+                  ]
+                },
+                {
+                  "type": "BLANK"
+                }
+              ]
+            },
             {
               "type": "CHOICE",
               "members": [
@@ -3412,7 +3430,6 @@
           ]
         }
       ]
-      }
     },
     "for_group": {
       "type": "SEQ",
@@ -7947,6 +7964,9 @@
     [
       "template"
     ],
+    [
+      "for_scope"
+    ],
     [
       "predicate"
     ],

src/node-types.json

@@ -2816,6 +2816,10 @@
     "type": "resetcycle",
     "named": false
   },
+  {
+    "type": "reversed",
+    "named": false
+  },
   {
     "type": "rjust",
     "named": false

test/corpus/for.txt

@@ -95,3 +95,353 @@ For With Empty
     (template
       (content)))
   (content))
+
+==================
+For With A Tag In Its Body
+==================
+
+{% for x in y %}
+{% if a %}b{% endif %}
+{% endfor %}
+
+---
+
+(template
+  (content)
+  (for_group
+    (for_scope
+      variable: (identifier)
+      (filtered_value
+        (value
+          (variable_attribute
+            (identifier))))
+      (template
+        (content)
+        (if_group
+          (predicate
+            (filtered_value
+              (value
+                (variable_attribute
+                  (identifier)))))
+          (template
+            (content)))
+        (content))))
+  (content))
+
+==================
+For With A Nested For
+==================
+
+{% for x in y %}
+{% for z in x %}a{% endfor %}
+{% endfor %}
+
+---
+
+(template
+  (content)
+  (for_group
+    (for_scope
+      variable: (identifier)
+      (filtered_value
+        (value
+          (variable_attribute
+            (identifier))))
+      (template
+        (content)
+        (for_group
+          (for_scope
+            variable: (identifier)
+            (filtered_value
+              (value
+                (variable_attribute
+                  (identifier))))
+            (template
+              (content))))
+        (content))))
+  (content))
+
+==================
+For With Tags In Both Branches
+==================
+
+{% for x in y %}
+{% if a %}b{% endif %}
+{% empty %}
+{% with c=1 %}d{% endwith %}
+{% endfor %}
+
+---
+
+(template
+  (content)
+  (for_group
+    (for_scope
+      variable: (identifier)
+      (filtered_value
+        (value
+          (variable_attribute
+            (identifier))))
+      (template
+        (content)
+        (if_group
+          (predicate
+            (filtered_value
+              (value
+                (variable_attribute
+                  (identifier)))))
+          (template
+            (content)))
+        (content)))
+    (template
+      (content)
+      (with_group
+        variable: (identifier)
+        (filtered_value
+          (value
+            (literal
+              (number))))
+        (template
+          (content)))
+      (content)))
+  (content))
+
+==================
+For With A Named Block In Its Body
+==================
+
+{% for x in y %}
+{% block b %}c{% endblock b %}
+{% endfor %}
+
+---
+
+(template
+  (content)
+  (for_group
+    (for_scope
+      variable: (identifier)
+      (filtered_value
+        (value
+          (variable_attribute
+            (identifier))))
+      (template
+        (content)
+        (block_group
+          name: (push_block)
+          (template
+            (content))
+          (pop_block))
+        (content))))
+  (content))
+
+==================
+For Nested In A Tag
+==================
+
+{% if a %}
+{% for x in y %}{% if b %}c{% endif %}{% endfor %}
+{% endif %}
+
+---
+
+(template
+  (content)
+  (if_group
+    (predicate
+      (filtered_value
+        (value
+          (variable_attribute
+            (identifier)))))
+    (template
+      (content)
+      (for_group
+        (for_scope
+          variable: (identifier)
+          (filtered_value
+            (value
+              (variable_attribute
+                (identifier))))
+          (template
+            (if_group
+              (predicate
+                (filtered_value
+                  (value
+                    (variable_attribute
+                      (identifier)))))
+              (template
+                (content))))))
+      (content)))
+  (content))
+
+==================
+For With An Empty Body
+==================
+
+{% for x in y %}{% endfor %}
+
+---
+
+(template
+  (content)
+  (for_group
+    (for_scope
+      variable: (identifier)
+      (filtered_value
+        (value
+          (variable_attribute
+            (identifier))))))
+  (content))
+
+==================
+For Reversed
+==================
+
+{% for x in y reversed %}
+a
+{% endfor %}
+
+---
+
+(template
+  (content)
+  (for_group
+    (for_scope
+      variable: (identifier)
+      (filtered_value
+        (value
+          (variable_attribute
+            (identifier))))
+      (template
+        (content))))
+  (content))
+
+==================
+For With Multiple Variables Reversed
+==================
+
+{% for k,v in y reversed %}
+a
+{% endfor %}
+
+---
+
+(template
+  (content)
+  (for_group
+    (for_scope
+      variable: (identifier)
+      variable: (identifier)
+      (filtered_value
+        (value
+          (variable_attribute
+            (identifier))))
+      (template
+        (content))))
+  (content))
+
+==================
+For With A Filtered Sequence Reversed
+==================
+
+{% for x in y|slice:":2" reversed %}
+a
+{% endfor %}
+
+---
+
+(template
+  (content)
+  (for_group
+    (for_scope
+      variable: (identifier)
+      (filtered_value
+        (value
+          (variable_attribute
+            (identifier)))
+        (filter_expression
+          (filter
+            argument: (value
+              (literal
+                (string))))))
+      (template
+        (content))))
+  (content))
+
+==================
+For Reversed With Empty
+==================
+
+{% for x in y reversed %}
+a
+{% empty %}
+b
+{% endfor %}
+
+---
+
+(template
+  (content)
+  (for_group
+    (for_scope
+      variable: (identifier)
+      (filtered_value
+        (value
+          (variable_attribute
+            (identifier))))
+      (template
+        (content)))
+    (template
+      (content)))
+  (content))
+
+==================
+For Reversed With A Tag In Its Body
+==================
+
+{% for x in y reversed %}
+{% if a %}b{% endif %}
+{% endfor %}
+
+---
+
+(template
+  (content)
+  (for_group
+    (for_scope
+      variable: (identifier)
+      (filtered_value
+        (value
+          (variable_attribute
+            (identifier))))
+      (template
+        (content)
+        (if_group
+          (predicate
+            (filtered_value
+              (value
+                (variable_attribute
+                  (identifier)))))
+          (template
+            (content)))
+        (content))))
+  (content))
+
+==================
+For With Reversed Twice
+:error
+==================
+
+{% for x in y reversed reversed %}a{% endfor %}
+
+---
+
+
+==================
+For With Reversed Before In
+:error
+==================
+
+{% for x reversed in y %}a{% endfor %}
+
+---