✨ support v-slot [RFC0001] (refs #39)

Author: mysticatea

docs/ast.md

@@ -130,7 +130,7 @@ interface VFilter <: Node {
 - `Reference#variable` is the variable which is defined by a `VElement`. If a reference uses a global variable or a member of VM, this is `null`.
 - `VForExpression` is an expression node like [ForInStatement] but it has an array as `left` property and does not have `body` property. This is the value of [`v-for` directives].
 - `VOnExpression` is an expression node like [BlockStatement] but it does not have braces. This is the value of [`v-on` directives] only if the `v-on` directive doesn't have that argument.
-- `VSlotScopeExpression` is an expression node like [VariableDeclarator]. This is the value of [`slot-scope` attribute] or the `scope` attribute of `<template>` elements.
+- `VSlotScopeExpression` is an expression node like [VariableDeclarator]. This is the value of [`v-slot` directives], [`slot-scope` attributes], and `scope` attributes.
 - `VFilterSequenceExpression` is an expression node for [Vue.js Filters](https://vuejs.org/v2/guide/filters.html) syntax.
 
 > Note: `vue-eslint-parser` transforms `v-for="(x, i) in list"` to `for(let [x, i] in list);` then gives the configured parser (`espree` by default) it. This implies that it needs the capability to parse ES2015 destructuring in order to parse [`v-for` directives].
@@ -273,5 +273,6 @@ This supports only HTML for now. However, I'm going to add other languages Vue.j
 
 [`v-for` directives]: https://vuejs.org/v2/api/#v-for
 [`v-on` directives]: https://vuejs.org/v2/api/#v-on
+[`v-slot` directives]: https://vuejs.org/v2/api/#v-slot
 [scope]: https://vuejs.org/v2/guide/components.html#Scoped-Slots
-[`slot-scope` attribute]: https://vuejs.org/v2/guide/components.html#Scoped-Slots
+[`slot-scope` attributes]: https://vuejs.org/v2/guide/components.html#Scoped-Slots

src/template/index.ts

@@ -279,9 +279,13 @@ function parseAttributeValue(
             parserOptions,
         )
     } else if (
+        directiveKey.name === "slot" ||
         directiveKey.name === "slot-scope" ||
         (tagName === "template" && directiveKey.name === "scope")
     ) {
+        if (directiveKey.name === "slot" && directiveKey.argument == null) {
+            directiveKey.argument = "default"
+        }
         result = parseSlotScopeExpression(
             node.value,
             locationCalculator,