Implementing JSON Schema validation (#71)

* initial work on json schemas
* improve schema validation
- simplify schemas
- validate references for properties
- set up enum values for animationType (properties.json)
* complete properties.json schema
* code style for schema files
* Rework travis config to lint json and validate schema
* Add notes about `property-reference` validator extension
* PR review fixes and related
- rephrase comments

.gitignore

@@ -0,0 +1 @@
+/node_modules/

.travis.yml

@@ -1,7 +1,3 @@
 language: node_js
-before_script:
-  - npm install jsonlint -g
-script:
-  - find . -name \*.json  | xargs -I {} jsonlint -q {}
-notifications:
-email: false
+sudo: false
+script: "npm run travis"

css/at-rules.schema.json

@@ -0,0 +1,103 @@
+{
+  "definitions": {
+    "stringOrPropertyList": {
+      "oneOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "array",
+          "minItems": 1,
+          "uniqueItems": true,
+          "items": {
+            "type": "string",
+            "property-reference": {
+              "comment": "property-reference is an extension to the JSON schema validator. Here it jumps 3 levels up in the hierarchy and tests if a value is an existing key in descriptors. See test/validate-schema.js for implementation details.",
+              "$data": "3"
+            }
+          }
+        }
+      ]
+    }
+  },
+  "type": "object",
+  "additionalProperties": {
+    "type": "object",
+    "additionalProperties": false,
+    "properties": {
+      "syntax": {
+        "type": "string"
+      },
+      "interfaces": {
+        "type": "array",
+        "items": {
+          "type": "string"
+        }
+      },
+      "groups": {
+        "type": "array",
+        "items": {
+          "type": "string"
+        }
+      },
+      "descriptors": {
+        "type": "object",
+        "additionalProperties": {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "syntax": {
+              "type": "string"
+            },
+            "media": {
+              "type": "string"
+            },
+            "initial": {
+              "$ref": "#/definitions/stringOrPropertyList"
+            },
+            "percentages": {
+              "$ref": "#/definitions/stringOrPropertyList"
+            },
+            "computed": {
+              "$ref": "#/definitions/stringOrPropertyList"
+            },
+            "order": {
+              "enum": [
+                "orderOfAppearance",
+                "uniqueOrder"
+              ]
+            },
+            "status": {
+              "enum": [
+                "standard",
+                "nonstandard",
+                "experimental"
+              ]
+            }
+          },
+          "required": [
+            "syntax",
+            "media",
+            "initial",
+            "percentages",
+            "computed",
+            "order",
+            "status"
+          ]
+        }
+      },
+      "status": {
+        "enum": [
+          "standard",
+          "nonstandard",
+          "experimental"
+        ]
+      }
+    },
+    "required": [
+      "syntax",
+      "groups",
+      "status"
+    ]
+  }
+}

css/properties.json

@@ -2581,7 +2581,7 @@
     "media": "visual",
     "inherited": false,
     "animationType": "basicShapeOtherwiseNo",
-    "percentages": "referenceBoxWhenSpecifiedOtherwiseBorderBox",
+    "percentages": "referToReferenceBoxWhenSpecifiedOtherwiseBorderBox",
     "groups": [
       "CSS Miscellaneous"
     ],