protected void pushOnAstLengthStack(int pos) {

	int stackLength = this.astLengthStack.length;
	if (++this.astLengthPtr >= stackLength) {
		System.arraycopy(
			this.astLengthStack, 0,
			this.astLengthStack = new int[stackLength + StackIncrement], 0,
			stackLength);
	}
	this.astLengthStack[this.astLengthPtr] = pos;
}