Add support for i18n tags

Resolves #5

This commit adds rules to consume `<i18n>` tags and highlight body text
as JSON or YAML.

Author: deathaxe

Vue Component.sublime-syntax

@@ -65,6 +65,7 @@ contexts:
     - meta_prepend: true
     - include: script-tag
     - include: style-tag
+    - include: i18n-tag
     - include: template-tag
 
 ###[ SCRIPT TAG ]#############################################################
@@ -535,6 +536,48 @@ contexts:
         3: source.sss.embedded.html
         4: comment.block.html punctuation.definition.comment.end.html
 
+###[ I18N TAG ]###############################################################
+
+  i18n-tag:
+    # https://github.com/kazupon/vue-i18n
+    - match: (<)((?i:i18n)){{tag_name_break}}
+      captures:
+        1: punctuation.definition.tag.begin.html
+        2: entity.name.tag.i18n.html
+      push: i18n-open-tag-content
+    - match: (</)((?i:i18n)){{tag_name_break}}
+      captures:
+        1: punctuation.definition.tag.begin.html
+        2: entity.name.tag.i18n.html
+        3: punctuation.definition.tag.end.html
+      push: i18n-close-tag-content
+
+  i18n-close-tag-content:
+    - meta_scope: meta.tag.i18n.end.html
+    - include: tag-end
+
+  i18n-open-tag-content:
+    - meta_scope: meta.tag.i18n.begin.html
+    - match: '>'
+      scope: punctuation.definition.tag.end.html
+      set: i18n-content
+    - include: tag-attributes
+    - include: tag-end-self-closing
+
+  i18n-content:
+    # expect json object or list
+    - match: (?=(?:^|\s*)[{\[])
+      embed: scope:source.json
+      embed_scope: source.json.embedded.html
+      escape: (?=(?:^\s*)?</(?i:i18n){{tag_name_break}})
+      pop: 1
+    # use yaml syntax otherwise (it also highlights json well!)
+    - match: (?=(?:^|\s*)\S)
+      embed: scope:source.yaml
+      embed_scope: source.yaml.embedded.html
+      escape: (?=(?:^\s*)?</(?i:i18n){{tag_name_break}})
+      pop: 1
+
 ###[ TEMPLATE TAG ]###########################################################
 
   template-tag:

tests/syntax_test_i18n.vue

@@ -0,0 +1,73 @@
+// SYNTAX TEST "Vue Component.sublime-syntax"
+
+<!--
+ Test i18n loader tags
+
+ https://github.com/kazupon/vue-i18n
+ -->
+
+<i18n>
+//^^^^ meta.tag.i18n.begin.html
+//^^^ entity.name.tag.i18n.html
+//   ^ punctuation.definition.tag.end.html
+//    ^ - source
+
+// <- source.yaml.embedded.html
+</i18n>
+//^^^^^ meta.tag.i18n.end.html
+//^^^^ entity.name.tag.i18n.html
+//    ^ punctuation.definition.tag.end.html
+
+<i18n>
+    {
+//  ^ source.json.embedded.html meta.mapping.json punctuation.section.mapping.begin.json
+      "en": {
+//    ^^^^ source.json.embedded.html meta.mapping.key.json string.quoted.double.json
+        "homePage": "Home",
+//     ^^^^^^^^^^^^^^^^^^^^^ source.json.embedded.html meta.mapping.value.json
+//      ^^^^^^^^^^ meta.mapping.key.json string.quoted.double.json
+//                ^ meta.mapping.json punctuation.separator.key-value.json
+//                  ^^^^^^ meta.mapping.value.json meta.string.json string.quoted.double.json
+      },
+//  ^^^ source.json.embedded.html meta.mapping.value.json meta.mapping.json
+    }
+//  ^ source.json.embedded.html meta.mapping.json punctuation.section.mapping.end.json
+</i18n>
+//^^^^^ meta.tag.i18n.end.html
+//^^^^ entity.name.tag.i18n.html
+//    ^ punctuation.definition.tag.end.html
+
+<i18n>
+    en:
+      homePage: Home
+//   ^^^^^^^^^^^^^^^^ source.yaml.embedded.html
+//    ^^^^^^^^ meta.mapping.key.yaml meta.string.yaml string.unquoted
+//            ^ meta.mapping.yaml punctuation.separator.key-value
+//              ^^^^ meta.string.yaml string.unquoted
+</i18n>
+//^^^^^ meta.tag.i18n.end.html
+//^^^^ entity.name.tag.i18n.html
+//    ^ punctuation.definition.tag.end.html
+
+<i18n
+    attr="value"
+//^^^^^^^^^^^^^^ meta.tag.i18n.begin.html
+//  ^^^^^^^^^^^^ meta.attribute-with-value.html
+//  ^^^^ entity.other.attribute-name.html
+//      ^ punctuation.separator.key-value.html
+//       ^^^^^^^ meta.string.html string.quoted.double.html
+//       ^ punctuation.definition.string.begin.html
+//             ^ punctuation.definition.string.end.html
+>
+// <- meta.tag.i18n.begin.html punctuation.definition.tag.end.html
+    en:
+      homePage: Home
+//   ^^^^^^^^^^^^^^^^ source.yaml.embedded.html
+//    ^^^^^^^^ meta.mapping.key.yaml meta.string.yaml string.unquoted
+//            ^ meta.mapping.yaml punctuation.separator.key-value
+//              ^^^^ meta.string.yaml string.unquoted
+</i18n
+//^^^^^ meta.tag.i18n.end.html
+//^^^^ entity.name.tag.i18n.html
+>
+// <- meta.tag.i18n.end.html punctuation.definition.tag.end.html