Add language support for GYB

package.json

@@ -83,6 +83,28 @@
         "filenamePatterns": [
           "*.tutorial"
         ]
+      },
+      {
+        "id": "swift-gyb",
+        "aliases": [
+          "Swift GYB"
+        ],
+        "extensions": [
+          ".swift.gyb"
+        ],
+        "configuration": "./swift-gyb.language-configuration.json"
+      }
+    ],
+    "grammars": [
+      {
+        "language": "swift-gyb",
+        "scopeName": "source.swift.gyb",
+        "path": "./syntaxes/swift-gyb.tmLanguage.json",
+        "embeddedLanguages": {
+          "meta.embedded.block.gyb": "python",
+          "meta.embedded.control.begin.gyb": "python",
+          "meta.embedded.expression.gyb": "python"
+        }
       }
     ],
     "snippets": [

swift-gyb.language-configuration.json

@@ -0,0 +1,19 @@
+{
+    "brackets": [
+        ["{", "}"]
+    ],
+    "autoClosingPairs": [
+        ["%{", "}%"],
+        ["${", "}"]
+    ],
+    "surroundingPairs": [
+        ["%{", "}%"],
+        ["${", "}"]
+    ],
+    "folding": {
+        "markers": {
+            "start": "^\\s*(?:%\\{|%[^\\{].*?:)",
+            "end": "^\\s*(?:\\}%|%\\s*end\\b)"
+        }
+    }
+}

syntaxes/swift-gyb.tmLanguage.json

@@ -0,0 +1,95 @@
+{
+    "$schema": "https://raw.githubusercontent.com/martinring/tmlanguage/master/tmlanguage.json",
+    "name": "Swift GYB",
+    "patterns": [
+        { "include": "#gyb-code-block" },
+        { "include": "#gyb-start-control-statement" },
+        { "include": "#gyb-end-control-statement" },
+        { "include": "#gyb-expression" },
+        { "include": "source.swift" }
+    ],
+    "repository": {
+        "gyb-code-block": {
+            "name": "meta.embedded.block.gyb",
+            "begin": "(%)\\{",
+            "beginCaptures": {
+                "1": { "name": "keyword.control.gyb" },
+                "0": { "name": "punctuation.section.block.begin.gyb" }
+            },
+            "end": "\\}(%)",
+            "endCaptures": {
+                "1": { "name": "keyword.control.gyb" },
+                "0": { "name": "punctuation.section.block.end.gyb" }
+            },
+            "patterns": [
+                { "include": "source.python" }
+            ]
+        },
+        "gyb-start-control-statement": {
+            "name": "meta.embedded.control.begin.gyb",
+            "begin": "(%)(?!\\{|\\s*end\\b).+?",
+            "beginCaptures": {
+                "1": { "name": "keyword.control.flow.gyb" }
+            },
+            "end": ":",
+            "endCaptures": {
+                "0": { "name": "punctuation.separator.colon.gyb" }
+            },
+            "patterns": [
+                { "include": "source.python" }
+            ]
+        },
+        "gyb-end-control-statement": {
+            "name": "meta.embedded.control.end.gyb",
+            "match": "%\\s*end\\b",
+            "captures": {
+                "0": { "name": "keyword.control.flow.gyb" }
+            }
+        },
+        "gyb-expression": {
+            "name": "meta.embedded.expression.gyb",
+            "begin": "(\\$)\\{",
+            "beginCaptures": {
+                "1": { "name": "variable.other.gyb" },
+                "0": { "name": "punctuation.section.expression.begin.gyb" }
+            },
+            "end": "\\}",
+            "endCaptures": {
+                "0": { "name": "punctuation.section.expression.end.gyb" }
+            },
+            "patterns": [
+                { "include": "source.python" }
+            ]
+        }
+    },
+    "injections": {
+        "source.swift": {
+            "patterns": [
+                { "include": "#gyb-code-block" },
+                { "include": "#gyb-start-control-statement" },
+                { "include": "#gyb-end-control-statement" },
+                { "include": "#gyb-expression" }
+            ]
+        },
+        "source.python": {
+            "patterns": [
+                { "include": "#gyb-code-block" },
+                { "include": "#gyb-start-control-statement" },
+                { "include": "#gyb-end-control-statement" },
+                { "include": "#gyb-expression" }
+            ]
+        },
+        "source.swift.gyb": {
+            "patterns": [
+                { "include": "#gyb-code-block" },
+                { "include": "#gyb-start-control-statement" },
+                { "include": "#gyb-end-control-statement" },
+                { "include": "#gyb-expression" }
+            ]
+        }
+    },
+    "scopeName": "source.swift.gyb",
+    "fileTypes": ["swift.gyb"],
+    "foldingStartMarker": "^\\s*(?:%\\{|%[^\\{].*?:)",
+    "foldingStopMarker": "^\\s*(?:\\}%|%\\s*end\\b)"
+}