gobbleSpaces() {
		let ch = this.code;
		// Whitespace
		while (ch === Jsep.SPACE_CODE
		|| ch === Jsep.TAB_CODE
		|| ch === Jsep.LF_CODE
		|| ch === Jsep.CR_CODE) {
			ch = this.expr.charCodeAt(++this.index);
		}
		this.runHook('gobble-spaces');
	}
Push `index` up to the next non-space character