Method prev

src/parser/streams/char-stream.ts:76–89

* カーソル位置を前の文字へ戻します。

()

	 * カーソル位置を前の文字へ戻します。
	*/
	public prev(): void {
		this.movePrev();
		this.decAddr();
		if (!this.startOfFile && this._char === '\n') {
			this.line--;
			const page = this.pages.get(this.pageIndex)!;
			const lastLineBreak = page.lastIndexOf('\n', this.address - 1);
			const lineStart = lastLineBreak >= 0 ? lastLineBreak + 1 : 0;
			const line = page.slice(lineStart, this.address);
			this.column = line.length;
		} else {
			this.column -= this._char!.length;
		}
	}

	private get isFirstPage(): boolean {
		return (this.pageIndex <= this.firstPageIndex);