Add syntax for as expressions

tree-sitter-dust/corpus/as.txt

@@ -0,0 +1,54 @@
+================================================================================
+Simple As
+================================================================================
+
+1 as int
+
+--------------------------------------------------------------------------------
+
+(root
+  (statement
+    (expression
+      (as
+        (expression
+          (value
+            (integer)))
+        (type)))))
+
+================================================================================
+As Function
+================================================================================
+
+foo as (int) -> int
+
+--------------------------------------------------------------------------------
+
+(root
+  (statement
+    (expression
+      (as
+        (expression
+          (identifier))
+        (type
+          (type)
+          (type))))))
+
+================================================================================
+As List in For Loop
+================================================================================
+
+for i in foobar as list {}
+
+--------------------------------------------------------------------------------
+
+(root
+  (statement
+    (for
+      (identifier)
+      (expression
+        (as
+          (expression
+            (identifier))
+          (type
+            (identifier))))
+      (block))))

tree-sitter-dust/grammar.js

@@ -43,6 +43,7 @@ module.exports = grammar({
     _expression_kind: $ =>
       prec.right(
         choice(
+          $.as,
           $.function_call,
           $.identifier,
           $.index,
@@ -65,6 +66,9 @@ module.exports = grammar({
         ),
       ),
 
+    as: $ =>
+      seq($.expression, 'as', $.type),
+
     pipe: $ =>
       prec(
         1,
@@ -181,10 +185,10 @@ module.exports = grammar({
     float: $ =>
       choice(
         /[-|+]?\d*[.][\d|e|-]*/,
-        "Infinity",
+        'Infinity',
-        "infinity",
+        'infinity',
-        "NaN",
+        'NaN',
-        "nan",
+        'nan',
       ),
 
     string: $ =>

tree-sitter-dust/src/grammar.json

@@ -115,6 +115,10 @@
       "content": {
         "type": "CHOICE",
         "members": [
+          {
+            "type": "SYMBOL",
+            "name": "as"
+          },
           {
             "type": "SYMBOL",
             "name": "function_call"
@@ -182,6 +186,23 @@
         }
       }
     },
+    "as": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "SYMBOL",
+          "name": "expression"
+        },
+        {
+          "type": "STRING",
+          "value": "as"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "type"
+        }
+      ]
+    },
     "pipe": {
       "type": "PREC",
       "value": 1,
@@ -507,7 +528,7 @@
       "members": [
         {
           "type": "PATTERN",
-          "value": "[-|+]?\\d*[.][\\d|e|f|-]*"
+          "value": "[-|+]?\\d*[.][\\d|e|-]*"
         },
         {
           "type": "STRING",

tree-sitter-dust/src/node-types.json

@@ -1,4 +1,23 @@
 [
+  {
+    "type": "as",
+    "named": true,
+    "fields": {},
+    "children": {
+      "multiple": true,
+      "required": true,
+      "types": [
+        {
+          "type": "expression",
+          "named": true
+        },
+        {
+          "type": "type",
+          "named": true
+        }
+      ]
+    }
+  },
   {
     "type": "assignment",
     "named": true,
@@ -122,6 +141,10 @@
       "multiple": false,
       "required": true,
       "types": [
+        {
+          "type": "as",
+          "named": true
+        },
         {
           "type": "command",
           "named": true
@@ -891,6 +914,10 @@
     "type": "args",
     "named": false
   },
+  {
+    "type": "as",
+    "named": false
+  },
   {
     "type": "assert_equal",
     "named": false