Class PlainCharacterCursor

packages/compiler/src/ml_parser/lexer.ts:1616–1735

}

class PlainCharacterCursor implements CharacterCursor {
  protected state: CursorState;
  protected file: ParseSourceFile;
  protected input: string;
  protected end: number;

  constructor(fileOrCursor: PlainCharacterCursor);
  constructor(fileOrCursor: ParseSourceFile, range: LexerRange);
  constructor(fileOrCursor: ParseSourceFile | PlainCharacterCursor, range?: LexerRange) {
    if (fileOrCursor instanceof PlainCharacterCursor) {
      this.file = fileOrCursor.file;
      this.input = fileOrCursor.input;
      this.end = fileOrCursor.end;

      const state = fileOrCursor.state;
      // Note: avoid using `{...fileOrCursor.state}` here as that has a severe performance penalty.
      // In ES5 bundles the object spread operator is translated into the `__assign` helper, which
      // is not optimized by VMs as efficiently as a raw object literal. Since this constructor is
      // called in tight loops, this difference matters.
      this.state = {
        peek: state.peek,
        offset: state.offset,
        line: state.line,
        column: state.column,
      };
    } else {
      if (!range) {
        throw new Error(
          'Programming error: the range argument must be provided with a file argument.',
        );
      }
      this.file = fileOrCursor;
      this.input = fileOrCursor.content;
      this.end = range.endPos;
      this.state = {
        peek: -1,
        offset: range.startPos,
        line: range.startLine,
        column: range.startCol,
      };
    }
  }

  clone(): PlainCharacterCursor {
    return new PlainCharacterCursor(this);
  }

  peek() {
    return this.state.peek;
  }
  charsLeft() {
    return this.end - this.state.offset;
  }
  diff(other: this) {
    return this.state.offset - other.state.offset;
  }

  advance(): void {