Underload in python

underload.py

def underload(code,stack=[],out="",emulator=0):
	depth=0
	tmp=""
	for cmd in code:
		try:
			if(depth==0):
				if(cmd=="~"):
					tmp1=stack[-1]
					tmp2=stack[-2]
					stack[-1]=tmp2
					stack[-2]=tmp1
				if(cmd==":"):stack.append(stack[-1])
				if(cmd=="!"):stack.pop()
				if(cmd=="*"):
					tmp1=stack.pop()
					tmp2=stack.pop()
					stack.append(tmp2+tmp1)
				if(cmd=="^"):
					#This should double the recursion limit. If anyone can make a better version I'd like to see it.
					if(stack[-1][-1]=="^"):
						stack,out=underload(stack.pop()[:-1],stack,out,1)
						stack,out=underload(stack.pop(),stack,out,1)
					else:stack,out=underload(stack.pop(),stack,out,1)
				if(cmd=="a"):stack.append("("+stack.pop()+")")
				if(cmd=="S"):out+=stack.pop()
			if(depth>0):tmp+=cmd
			if(cmd=="("):depth+=1
			if(cmd==")"):
				depth-=1
				if(depth==0):
					stack.append(tmp[:-1])
					tmp=""
			if(depth<0):raise Exception("UNDERLOAD: Depth has gone below 0")
		except KeyboardInterrupt:
			break
	if(emulator==1):
		return(stack,out)
	else:
		return(out)