fix(snippets): expand variables in condition

fix neoclide/coc-snippets#350

src/__tests__/snippets/parser.test.ts

@@ -1,7 +1,7 @@
 /* eslint-disable */
 import * as assert from 'assert'
 import { EvalKind } from '../../snippets/eval'
-import { Choice, CodeBlock, ConditionString, FormatString, Marker, Placeholder, Scanner, SnippetParser, Text, TextmateSnippet, TokenType, Transform, transformEscapes, Variable } from '../../snippets/parser'
+import { Choice, CodeBlock, ConditionMarker, ConditionString, FormatString, Marker, Placeholder, Scanner, SnippetParser, Text, TextmateSnippet, TokenType, Transform, transformEscapes, Variable } from '../../snippets/parser'
 
 describe('SnippetParser', () => {
 
@@ -224,6 +224,22 @@ describe('SnippetParser', () => {
     assertText('far{{id:bern {{id2:basel}}}}boo', 'far{{id:bern {{id2:basel}}}}boo')
   })
 
+  test('Parser ConditionMarker', () => {
+    let m = new ConditionMarker(1,
+      [new Text('a '), new FormatString(1)],
+      [new Text('b '), new FormatString(2)],
+    )
+    let val = m.resolve('', ['', 'foo', 'bar'])
+    expect(val).toBe('b bar')
+    val = m.resolve('x', ['', 'foo', 'bar'])
+    expect(val).toBe('a foo')
+    m.addIfMarker(new Text('if'))
+    m.addElseMarker(new Text('else'))
+    let s = m.toTextmateString()
+    expect(s).toBe('(?1:a ${1}if:b ${2}else)')
+    expect(m.clone()).toBeDefined()
+  })
+
   test('Parser, TM text', () => {
     assertTextAndMarker('foo${1:bar}}', 'foobar}', Text, Placeholder, Text)
     assertTextAndMarker('foo${1:bar}${2:foo}}', 'foobarfoo}', Text, Placeholder, Placeholder, Text)
@@ -489,8 +505,11 @@ describe('SnippetParser', () => {
     expect(snip.toString()).toBe('foo f_oo')
     snip = p.parse('${1:foo} ${1/^\\w//}')
     expect(snip.toString()).toBe('foo oo')
+    snip = p.parse('${1:Foo} ${1/^(\\w+)$/\\u$1 (?1:-\\l$1)/g}')
+    expect(snip.toString()).toBe('Foo Foo -foo')
   })
 
+
   test('Parser, convert ultisnips regex', () => {
     const p = new SnippetParser(true)
     let snip = p.parse('${1:foo} ${1/^\\A/_/}')

src/snippets/parser.ts

@@ -5,7 +5,7 @@ import { defaultValue } from '../util'
 import { groupBy } from '../util/array'
 import { CharCode } from '../util/charCode'
 import { unidecode } from '../util/node'
-import { getCharIndexes, toText } from '../util/string'
+import { iterateCharacter, toText } from '../util/string'
 import { convertRegex, evalCode, EvalKind, executePythonCode, getVariablesCode, prepareMatchCode, UltiSnippetContext } from './eval'
 const logger = createLogger('snippets-parser')
 const ULTISNIP_VARIABLES = ['VISUAL', 'YANK', 'UUID']
@@ -419,18 +419,27 @@ export class Transform extends Marker {
     let ret = ''
     let backslashIndexes: number[] = []
     for (const marker of this._children) {
+      let val = ''
+      let len = ret.length
       if (marker instanceof FormatString) {
-        let val = marker.resolve(groups[marker.index] || '')
+        val = marker.resolve(groups[marker.index] ?? '')
         if (this.ultisnip && val.indexOf('\\') !== -1) {
-          let s = ret.length
-          backslashIndexes.push(...getCharIndexes(val, '\\').map(i => i + s))
+          for (let idx of iterateCharacter(val, '\\')) {
+            backslashIndexes.push(len + idx)
+          }
         }
-        ret += val
       } else if (marker instanceof ConditionString) {
-        ret += marker.resolve(groups[marker.index])
+        val = marker.resolve(groups[marker.index])
+        if (this.ultisnip) {
+          val = val.replace(/(?<!\\)\$(\d+)/g, (...args) => {
+            return groups[Number(args[1])] ?? ''
+          })
+        }
       } else {
-        ret += marker.toString()
+        val = marker.toString()
       }
+
+      ret += val
     }
     if (this.ascii) ret = unidecode(ret)
     return this.ultisnip ? transformEscapes(ret, backslashIndexes) : ret
@@ -486,6 +495,42 @@ export class ConditionString extends Marker {
   }
 }
 
+export class ConditionMarker extends Marker {
+  constructor(
+    public readonly index: number,
+    protected ifMarkers: Marker[] = [],
+    protected elseMarkers: Marker[] = []
+  ) {
+    super()
+  }
+
+  public resolve(value: string, groups: string[]): string {
+    let fn = (p: string, c: Marker): string => {
+      return p + (c instanceof FormatString ? c.resolve(groups[c.index]) : c.toString())
+    }
+    if (value) return this.ifMarkers.reduce(fn, '')
+    return this.elseMarkers.reduce(fn, '')
+  }
+
+  public addIfMarker(marker: Marker) {
+    this.ifMarkers.push(marker)
+  }
+
+  public addElseMarker(marker: Marker) {
+    this.elseMarkers.push(marker)
+  }
+
+  public toTextmateString(): string {
+    let ifValue = this.ifMarkers.reduce((p, c) => p + c.toTextmateString(), '')
+    let elseValue = this.elseMarkers.reduce((p, c) => p + c.toTextmateString(), '')
+    return '(?' + this.index + ':' + ifValue + (elseValue.length > 0 ? ':' + elseValue : '') + ')'
+  }
+
+  public clone(): ConditionMarker {
+    return new ConditionMarker(this.index, this.ifMarkers.map(m => m.clone()), this.elseMarkers.map(m => m.clone()))
+  }
+}
+
 export class FormatString extends Marker {
 
   constructor(
@@ -1572,6 +1617,7 @@ export class SnippetParser {
       return false
     }
     let text = this._until(TokenType.CloseParen, true)
+    // TODO parse ConditionMarker for ultisnip
     if (text) {
       let i = 0
       while (i < text.length) {

src/util/string.ts

@@ -106,6 +106,12 @@ export function getCharIndexes(input: string, character: string): number[] {
   return res
 }
 
+export function* iterateCharacter(input: string, character: string): Iterable<number> {
+  for (let i = 0; i < input.length; i++) {
+    if (input[i] == character) yield i
+  }
+}
+
 export function isHighSurrogate(codePoint: number): boolean {
   return codePoint >= 0xd800 && codePoint <= 0xdbff
 }