fix(snippets): check inner placeholder first

Fix neoclide/coc-snippets#339

src/__tests__/snippets/parser.test.ts

@@ -243,7 +243,6 @@ describe('SnippetParser', () => {
   test('Parser, TM text', () => {
     assertTextAndMarker('foo${1:bar}}', 'foobar}', Text, Placeholder, Text)
     assertTextAndMarker('foo${1:bar}${2:foo}}', 'foobarfoo}', Text, Placeholder, Placeholder, Text)
-
     assertTextAndMarker('foo${1:bar\\}${2:foo}}', 'foobar}foo', Text, Placeholder)
 
     let [, placeholder] = new SnippetParser().parse('foo${1:bar\\}${2:foo}}').children
@@ -1102,6 +1101,12 @@ describe('SnippetParser', () => {
     assertMarker(snippet, Placeholder)
   })
 
+  test('Placeholder nestedPlaceholderCount', function() {
+    let { children } = new SnippetParser().parse('${1:foo${2:bar}}')
+    let placeholder = children[0] as Placeholder
+    assert.equal(placeholder.nestedPlaceholderCount, 1)
+  })
+
   test('snippets variable not resolved in JSON proposal #52931', function() {
     assertTextAndMarker('FOO${1:/bin/bash}', 'FOO/bin/bash', Text, Placeholder)
   })

src/__tests__/snippets/snippet.test.ts

@@ -295,8 +295,14 @@ describe('CocSnippet', () => {
     })
 
     it('should compares placeholders', () => {
-      expect(comparePlaceholder({ primary: false, index: 1 }, { primary: false, index: 0 })).toBe(-1)
-      expect(comparePlaceholder({ primary: true, index: 1 }, { primary: false, index: 1 })).toBe(-1)
+      let arr = [
+        { primary: false, index: 1, nestCount: 2 },
+        { primary: true, index: 2, nestCount: 1 },
+        { primary: false, index: 3, nestCount: 0 },
+      ]
+      arr.sort(comparePlaceholder)
+      let indexes = arr.map(p => p.index)
+      expect(indexes).toEqual([3, 2, 1])
     })
   })
 

src/snippets/parser.ts

@@ -334,6 +334,13 @@ export class Placeholder extends TransformableMarker {
       : undefined
   }
 
+  public get nestedPlaceholderCount(): number {
+    if (this.transform) return 0
+    return this._children.reduce((p, marker) => {
+      return p + (marker instanceof Placeholder ? 1 + marker.nestedPlaceholderCount : 0)
+    }, 0)
+  }
+
   public toTextmateString(): string {
     let transformString = ''
     if (this.transform) {

src/snippets/snippet.ts

@@ -23,6 +23,7 @@ export interface CocSnippetPlaceholder {
   before: string
   // snippet text after
   after: string
+  nestCount: number
 }
 
 export class CocSnippet {
@@ -261,6 +262,7 @@ export class CocSnippet {
         character: position.line == 0 ? character + position.character : position.character
       }
       let index: number
+      let nestCount = 0
       if (p instanceof Snippets.Variable) {
         let key = p.name
         if (variableIndexMap.has(key)) {
@@ -272,12 +274,14 @@ export class CocSnippet {
         }
       } else {
         index = p.index
+        nestCount = p.nestedPlaceholderCount
       }
       const value = p.toString()
       const end = getEnd(position, value)
       let res: CocSnippetPlaceholder = {
         index,
         value,
+        nestCount,
         marker: p,
         transform: !!p.transform,
         range: Range.create(start, getEnd(start, value)),
@@ -459,7 +463,9 @@ export function shouldFormat(snippet: string): boolean {
   return false
 }
 
-export function comparePlaceholder(a: { primary: boolean, index: number }, b: { primary: boolean, index: number }): number {
+export function comparePlaceholder(a: { primary: boolean, index: number, nestCount: number }, b: { primary: boolean, index: number, nestCount: number }): number {
+  // check inner placeholder first
+  if (a.nestCount !== b.nestCount) return a.nestCount - b.nestCount
   if (a.primary !== b.primary) return a.primary ? -1 : 1
   if (a.index == 0 || b.index == 0) return a.index == 0 ? 1 : -1
   return a.index - b.index