feat: add support for feature gates

fixes: #34

Signed-off-by: Gordon Smith <GordonJSmith@gmail.com>

Author: GordonSmith

.vscode/launch.json

@@ -13,7 +13,7 @@
       "args": [
         "--disable-extensions",
         "--extensionDevelopmentPath=${workspaceFolder}",
-        "${workspaceRoot}/tests/grammar/integration"
+        "${workspaceRoot}/tests/grammar"
       ]
     }
   ]

syntaxes/wit.tmLanguage.json

@@ -12,6 +12,9 @@
     {
       "include": "#comment"
     },
+    {
+      "include": "#feature-gate"
+    },
     {
       "include": "#package"
     },
@@ -34,6 +37,112 @@
       "comment": "whitespace token",
       "match": "\\s+"
     },
+    "feature-gate": {
+      "name": "meta.feature-gate.wit",
+      "comment": "Feature gate annotations like @unstable, @since, @deprecated",
+      "patterns": [
+        {
+          "name": "meta.annotation.unstable.wit",
+          "begin": "(@unstable)(\\()",
+          "beginCaptures": {
+            "1": {
+              "name": "keyword.control.unstable.wit"
+            },
+            "2": {
+              "name": "punctuation.brackets.round.begin.wit"
+            }
+          },
+          "patterns": [
+            {
+              "include": "#feature-gate-content"
+            }
+          ],
+          "end": "(\\))",
+          "endCaptures": {
+            "1": {
+              "name": "punctuation.brackets.round.end.wit"
+            }
+          }
+        },
+        {
+          "name": "meta.annotation.since.wit",
+          "begin": "(@since)(\\()",
+          "beginCaptures": {
+            "1": {
+              "name": "keyword.control.since.wit"
+            },
+            "2": {
+              "name": "punctuation.brackets.round.begin.wit"
+            }
+          },
+          "patterns": [
+            {
+              "include": "#feature-gate-content"
+            }
+          ],
+          "end": "(\\))",
+          "endCaptures": {
+            "1": {
+              "name": "punctuation.brackets.round.end.wit"
+            }
+          }
+        },
+        {
+          "name": "meta.annotation.deprecated.wit",
+          "begin": "(@deprecated)(\\()",
+          "beginCaptures": {
+            "1": {
+              "name": "keyword.control.deprecated.wit"
+            },
+            "2": {
+              "name": "punctuation.brackets.round.begin.wit"
+            }
+          },
+          "patterns": [
+            {
+              "include": "#feature-gate-content"
+            }
+          ],
+          "end": "(\\))",
+          "endCaptures": {
+            "1": {
+              "name": "punctuation.brackets.round.end.wit"
+            }
+          }
+        }
+      ]
+    },
+    "feature-gate-content": {
+      "name": "meta.feature-gate-content.wit",
+      "comment": "Content inside feature gate annotations",
+      "patterns": [
+        {
+          "include": "#comment"
+        },
+        {
+          "name": "meta.feature-gate-parameter.wit",
+          "match": "\\b(feature|version)\\s*(=)\\s*([^\\s,)]+|\"[^\"]*\")",
+          "captures": {
+            "1": {
+              "name": "variable.parameter.feature-gate.wit"
+            },
+            "2": {
+              "name": "keyword.operator.assignment.wit"
+            },
+            "3": {
+              "name": "string.quoted.feature-gate.wit"
+            }
+          }
+        },
+        {
+          "name": "punctuation.comma.wit",
+          "match": ","
+        },
+        {
+          "include": "#whitespace"
+        }
+      ]
+    },
     "comment": {
       "patterns": [
         {
@@ -320,7 +429,7 @@
     "world": {
       "name": "meta.world-item.wit",
       "comment": "Syntax for WIT like `world \"id\" {`",
-      "begin": "^\\b(default\\s+)?(world)\\s+%?((?<![\\-\\w])([a-z][0-9a-z]*|[A-Z][0-9A-Z]*)(([\\-])([a-z][0-9a-z]*|[A-Z][0-9A-Z]*))*)\\s*(\\{)",
+      "begin": "^\\s*\\b(default\\s+)?(world)\\s+%?((?<![\\-\\w])([a-z][0-9a-z]*|[A-Z][0-9A-Z]*)(([\\-])([a-z][0-9a-z]*|[A-Z][0-9A-Z]*))*)\\s*(\\{)",
       "beginCaptures": {
         "1": {
           "name": "storage.modifier.default.world-item.wit"
@@ -339,6 +448,9 @@
         {
           "include": "#comment"
         },
+        {
+          "include": "#feature-gate"
+        },
         {
           "name": "meta.export-item.wit",
           "comment": "Syntax for WIT like `export \"id\"`",
@@ -510,7 +622,7 @@
     "interface": {
       "name": "meta.interface-item.wit",
       "comment": "Syntax for WIT like `interface \"id\" {`",
-      "begin": "^\\b(default\\s+)?(interface)\\s+%?((?<![\\-\\w])([a-z][0-9a-z]*|[A-Z][0-9A-Z]*)(([\\-])([a-z][0-9a-z]*|[A-Z][0-9A-Z]*))*)\\s*(\\{)",
+      "begin": "^\\s*\\b(default\\s+)?(interface)\\s+%?((?<![\\-\\w])([a-z][0-9a-z]*|[A-Z][0-9A-Z]*)(([\\-])([a-z][0-9a-z]*|[A-Z][0-9A-Z]*))*)\\s*(\\{)",
       "beginCaptures": {
         "1": {
           "name": "storage.modifier.default.interface-item.wit"
@@ -529,6 +641,9 @@
         {
           "include": "#comment"
         },
+        {
+          "include": "#feature-gate"
+        },
         {
           "include": "#interface-items"
         },
@@ -592,6 +707,9 @@
     "interface-items": {
       "name": "meta.interface-items.wit",
       "patterns": [
+        {
+          "include": "#feature-gate"
+        },
         {
           "include": "#typedef-item"
         },
@@ -606,6 +724,9 @@
     "typedef-item": {
       "name": "meta.typedef-item.wit",
       "patterns": [
+        {
+          "include": "#feature-gate"
+        },
         {
           "include": "#resource"
         },
@@ -1245,6 +1366,9 @@
         {
           "include": "#comment"
         },
+        {
+          "include": "#feature-gate"
+        },
         {
           "name": "meta.constructor-type.wit",
           "begin": "\\b(constructor)\\b",
@@ -1307,6 +1431,9 @@
         }
       },
       "patterns": [
+        {
+          "include": "#feature-gate"
+        },
         {
           "include": "#function-definition"
         },
@@ -1434,4 +1561,4 @@
       }
     }
   }
-}
+}

tests/grammar/integration/feature-gates.wit

@@ -0,0 +1,50 @@
+package test:feature-gates@1.0.0;
+
+@unstable(feature = experimental-interface)
+interface experimental {
+    @since(version = 1.1.0)
+    stable-func: func(input: string) -> string;
+    
+    @unstable(feature = new-api)
+    experimental-func: func(data: list<u8>) -> result<string, string>;
+    
+    @deprecated(version = 2.0.0)
+    old-func: func();
+}
+
+@since(version = 1.0.0)
+interface stable-interface {
+    basic-func: func();
+    
+    @deprecated(version = 1.5.0)
+    deprecated-method: func(x: u32);
+}
+
+@unstable(feature = future-world)
+world feature-world {
+    @since(version = 1.0.0)
+    export stable: interface {
+        get-version: func() -> string;
+    }
+    
+    @unstable(feature = beta-import)
+    import experimental: interface {
+        @unstable(feature = alpha-feature)
+        test-method: func() -> bool;
+    }
+}
+
+@since(version = 1.2.0)
+interface resources {
+    @unstable(feature = experimental-resource)
+    resource connection {
+        @since(version = 1.2.0)
+        constructor(url: string);
+        
+        @unstable(feature = async-methods)
+        connect: func() -> result<(), string>;
+        
+        @deprecated(version = 2.0.0)
+        disconnect: func();
+    }
+}