Add support for parsing !reference tag in GitLab CI YAML files

README.md

@@ -8,6 +8,7 @@ In additional to parsing YAML to AST, it has following features:
 
 * restoration after the errors and reporting errors as a part of AST nodes.
 * built-in support for `!include` tag used in RAML
+* built-in support fot `!reference` tag used in Gitlab CI.
 
 ## Usage
 The type information below is relevant when using TypeScript, if using from JavaScript only the field/method information is relevant.
@@ -17,7 +18,7 @@ The type information below is relevant when using TypeScript, if using from Java
 ### YAMLNode
 `YAMLNode` class is an ancestor for all node kinds.
 It's `kind` field determine node kind, one of `Kind` enum:
-  * `SCALAR`, `MAPPING`, `MAP`, `SEQ`, `ANCHOR_REF` or `INCLUDE_REF`.
+  * `SCALAR`, `MAPPING`, `MAP`, `SEQ`, `ANCHOR_REF`, `INCLUDE_REF` or `REFERENCE_REF`.
 
 After node kind is determined, it can be cast to one of the `YAMLNode` descendants types:
  * `YAMLScalar`, `YAMLMapping`, `YamlMap`, `YAMLSequence` or `YAMLAnchorReference`.

src/dumper.ts

@@ -227,6 +227,10 @@ function writeScalar(state, object, level) {
     state.dump=""+object;//FIXME
     return;
   }
+  if (object.indexOf("!reference")==0){
+    state.dump=""+object;//FIXME
+    return;
+  }
   if (object.indexOf("!$$$novalue")==0){
     state.dump="";//FIXME
     return;

src/loader.ts

@@ -1574,7 +1574,15 @@ function composeNode(state:State, parentIndent, nodeContext, allowToSeek, allowC
   }
 
   if (null !== state.tag && '!' !== state.tag) {
-    if (state.tag=="!include"){
+    if (state.tag == "!reference") {
+      if (!state.result) {
+        state.result = ast.newScalar();
+        state.result.startPosition = state.position;
+        state.result.endPosition = state.position;
+        throwError(state, "!reference without value");
+      }
+      state.result.kind = ast.Kind.REFERENCE_REF;
+    } else if (state.tag=="!include"){
         if (!state.result){
             state.result=ast.newScalar();
             state.result.startPosition=state.position;

src/yamlAST.ts

@@ -9,7 +9,8 @@ export enum Kind{
     MAP,
     SEQ,
     ANCHOR_REF,
-    INCLUDE_REF
+    INCLUDE_REF,
+    REFERENCE_REF
 }
 
 export interface YAMLDocument {