support referencing functions by name

Author: epoberezkin

.travis.yml

@@ -4,6 +4,7 @@ before_script:
 node_js:
   - "4"
   - "5"
+  - "6"
 after_script:
   - codeclimate-test-reporter < coverage/lcov.info
   - coveralls < coverage/lcov.info

lib/evaluation.js

@@ -11,4 +11,5 @@ function Evaluation(js, script, data, refPrefix) {
   this.refPrefixRegexp = new RegExp('^' + refPrefix);
   this.evaluatedRefs = {};
   this.pendingRefs = {};
+  this.functions = {};
 }

lib/instruction_keywords.js

@@ -144,15 +144,27 @@ function eval$delay(params) {
  * @return {Function} Function that returns Script or synchronous/asynchronous value
  */
 function eval$func(params) {
+  var funcBody = params.$func;
+  if (typeof funcBody == 'string') {
+    if (Object.keys(params).length > 1)
+      throw new Error('reference to function "' + funcBody + '" has other properties');
+    if (!(funcBody in this.functions))
+      throw new Error('unknown function "' + funcBody + '"');
+    return this.functions[funcBody];
+  }
+
   var self = this;
-  var valid = this.js.validate(params.$func);
-  if (valid) return Promise.resolve(func);
-  var err = this.js.ajv.ValidationError(this.js.validate.errors);
-  return Promise.reject(err);
+  var valid = this.js.validate(funcBody);
+  if (valid) {
+    var pFunc = Promise.resolve(func);
+    if (params.$name) this.functions[params.$name] = pFunc;
+    return pFunc;
+  }
+  throw new this.js.ajv.ValidationError(this.js.validate.errors);
 
   function func() {
     var data = params.$args ? prepareArguments(arguments) : self.data;
-    var script = JSON.parse(JSON.stringify(params.$func));
+    var script = JSON.parse(JSON.stringify(funcBody));
     return self.js.evaluate(script, data);
   }
 

package.json

@@ -36,8 +36,8 @@
     "coveralls": "^2.11.6",
     "eslint": "^2.2.0",
     "istanbul": "^0.4.2",
-    "jsonscript-test": "^0.2.0",
-    "jsonscript-test-suite": "^0.2.1",
+    "jsonscript-test": "^0.2.1",
+    "jsonscript-test-suite": "^0.2.2",
     "mocha": "^2.4.5",
     "pre-commit": "^1.1.2"
   }