perf: introduce AST to avoid reparse

src/tokens/delimited-token.ts

@@ -0,0 +1,32 @@
+import { Token } from './token'
+import { TokenKind } from '../parser/token-kind'
+import { last } from '../util/underscore'
+
+export abstract class DelimitedToken extends Token {
+  public trimLeft = false
+  public trimRight = false
+  public content: string
+  public constructor (
+    kind: TokenKind,
+    content: string,
+    input: string,
+    begin: number,
+    end: number,
+    trimLeft: boolean,
+    trimRight: boolean,
+    file?: string
+  ) {
+    super(kind, input, begin, end, file)
+    this.content = this.getText()
+    const tl = content[0] === '-'
+    const tr = last(content) === '-'
+    this.content = content
+      .slice(
+        tl ? 1 : 0,
+        tr ? -1 : content.length
+      )
+      .trim()
+    this.trimLeft = tl || trimLeft
+    this.trimRight = tr || trimRight
+  }
+}