add True, False, None

CLAUDE.md

@@ -277,6 +277,12 @@ documentation or memory. Both checks are worth repeating whenever tags, filters
 
 - Django has no number token: `[\w.]+` is one lexeme and `int()`/`float()` decides whether it is a literal,
   so `1a`, `1e`, `0x1f`, `1.2.3`, `1__0` and `1.` are variable _lookups_ there and errors here.
+- Django has no boolean or `None` token either. `True`, `False` and `None` are lookups, which resolve
+  because `BaseContext._reset_dicts` seeds every context with `{"True": True, "False": False, "None": None}`.
+  They are `boolean` and `none` literals here, so that a tool reading `queries/locals.scm` does not count
+  them as references to something the template never defines. Shadowing still parses — `{% with True=1 %}`
+  binds an `identifier`, because the keyword is not valid where a binding name is — but `{{ True.x }}` is
+  an error here and an ordinary two-part lookup in Django, which renders `string_if_invalid`.
 - A `with` binding written twice (`{% with a=1 a=2 %}`, and the same in `{% include %}` and
   `{% blocktranslate %}`) is an error here and not in Django, where `token_kwargs` builds a dict and the
   later value wins. It has no use, so it is treated as the mistake it almost certainly is.

grammar.js

@@ -342,7 +342,8 @@ const django = grammar({
       seq($.value, optional(seq("|", $.filter_expression))),
     filter_expression: ($) => seq($.filter, repeat(seq("|", $.filter))),
     value: ($) => choice($.literal, $.variable_attribute),
-    literal: ($) => choice($.number, $.string, $.translated_string),
+    literal: ($) =>
+      choice($.number, $.string, $.translated_string, $.boolean, $.none),
     // digits, with single underscores allowed between them, as Python's
     // int() and float() accept ("1_000") and Django's Variable relies on
     number: ($) =>
@@ -354,6 +355,8 @@ const django = grammar({
      * string: "_( 'a' )" is a syntax error there, not a translated literal.
      */
     translated_string: ($) => seq("_(", $.string, ")"),
+    boolean: ($) => choice("True", "False"),
+    none: ($) => "None",
     attribute: ($) => /[a-zA-Z0-9][a-zA-Z0-9_]*(?:\.[a-zA-Z0-9][a-zA-Z0-9_]*)*/,
     variable_attribute: ($) =>
       seq($.identifier, optional(seq(".", $.attribute))),

queries/highlights.scm

@@ -41,6 +41,8 @@ variable: (identifier) @variable.parameter
 
 (number) @number
 (string) @string
+(boolean) @constant.builtin
+(none) @constant.builtin
 
 (library
     (identifier) @module)

src/grammar.json

@@ -122,6 +122,14 @@
         {
           "type": "SYMBOL",
           "name": "translated_string"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "boolean"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "none"
         }
       ]
     },
@@ -150,6 +158,23 @@
         }
       ]
     },
+    "boolean": {
+      "type": "CHOICE",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "True"
+        },
+        {
+          "type": "STRING",
+          "value": "False"
+        }
+      ]
+    },
+    "none": {
+      "type": "STRING",
+      "value": "None"
+    },
     "attribute": {
       "type": "PATTERN",
       "value": "[a-zA-Z0-9][a-zA-Z0-9_]*(?:\\.[a-zA-Z0-9][a-zA-Z0-9_]*)*"

src/node-types.json

@@ -396,6 +396,11 @@
       ]
     }
   },
+  {
+    "type": "boolean",
+    "named": true,
+    "fields": {}
+  },
   {
     "type": "cache_clause",
     "named": true,
@@ -1699,6 +1704,14 @@
       "multiple": false,
       "required": true,
       "types": [
+        {
+          "type": "boolean",
+          "named": true
+        },
+        {
+          "type": "none",
+          "named": true
+        },
         {
           "type": "number",
           "named": true
@@ -2650,6 +2663,14 @@
     "type": ">=",
     "named": false
   },
+  {
+    "type": "False",
+    "named": false
+  },
+  {
+    "type": "True",
+    "named": false
+  },
   {
     "type": "_(",
     "named": false
@@ -3074,6 +3095,10 @@
     "type": "media",
     "named": false
   },
+  {
+    "type": "none",
+    "named": true
+  },
   {
     "type": "noop",
     "named": false

test/corpus/if.txt

@@ -156,3 +156,29 @@ If Operator Adjacent To Value
 {% if 1and 2 %}yes{% endif %}
 
 ---
+
+==================
+If Is Not None
+==================
+
+{% if status is not None %}yes{% endif %}
+
+---
+
+(template
+  (content)
+  (if_group
+    (if_clause
+      (predicate
+        (filtered_value
+          (value
+            (variable_attribute
+              (identifier))))
+        (binaryOperator)
+        (filtered_value
+          (value
+            (literal
+              (none)))))
+      (template
+        (content))))
+  (content))

test/corpus/template_variable.txt

@@ -361,3 +361,103 @@ Template Variable With Spaced Filter
       (filter_expression
         (filter))))
   (content))
+
+==================
+Template Variable True
+==================
+
+{{ True }}
+
+---
+
+(template
+  (content)
+  (template_variable
+    (filtered_value
+      (value
+        (literal
+          (boolean)))))
+  (content))
+
+==================
+Template Variable False
+==================
+
+{{ False }}
+
+---
+
+(template
+  (content)
+  (template_variable
+    (filtered_value
+      (value
+        (literal
+          (boolean)))))
+  (content))
+
+==================
+Template Variable None
+==================
+
+{{ None }}
+
+---
+
+(template
+  (content)
+  (template_variable
+    (filtered_value
+      (value
+        (literal
+          (none)))))
+  (content))
+
+==================
+Template Variable Boolean As Filter Argument
+==================
+
+{{ value|default:True }}
+
+---
+
+(template
+  (content)
+  (template_variable
+    (filtered_value
+      (value
+        (variable_attribute
+          (identifier)))
+      (filter_expression
+        (filter
+          argument: (value
+            (literal
+              (boolean)))))))
+  (content))
+
+==================
+Template Variable Name Beginning With A Literal
+==================
+
+{{ Truest }}
+
+---
+
+(template
+  (content)
+  (template_variable
+    (filtered_value
+      (value
+        (variable_attribute
+          (identifier)))))
+  (content))
+
+==================
+Template Variable Attribute Of A Literal
+:error
+==================
+
+{{ None.x }}
+
+---
+

test/corpus/with.txt

@@ -111,3 +111,24 @@ With Repeating A Binding Of The Tag Before It
       (template
         (content))))
   (content))
+
+==================
+With A Binding Named After A Literal
+==================
+
+{% with True=1 %}a{% endwith %}
+
+---
+
+(template
+  (content)
+  (with_group
+    (with_clause
+      variable: (identifier)
+      (filtered_value
+        (value
+          (literal
+            (number))))
+      (template
+        (content))))
+  (content))