# simsubs.py -- A library for setting/unsetting defines and performing substitutions of said defines
# @YAHOO@
#
# Michael Thomas <mthomas@cct.lsu.edu>
# Center for Computation & Technology
# Louisiana State University 
#

import re

class DefineDatabase:
	def __init__(self):
		self.Reset()
	
	def Reset(self):
		self.defines = dict()
	
	def Set(self, define, value):
		self.defines[define] = value
	
	def Unset(self, define):
		try:
			del self.defines[define]
		except KeyError:
			return
	
	def Has(self, define):
		return self.defines.has_key(define)
		
	def Get(self, define):
		if self.Has(define):
			return self.defines[define]
		
		return None

	def Sub(self, define, ss):
		if self.Has(define):
			macro = "@%s@" % define
			return self.PerformSub(ss, macro, self.defines[define])
		
		return ss
	
	def PerformSub(self, ss, macro, value):
		if value is not str:
			value = str(value)

		return ss.replace(macro, value)

	def SubAll(self, ss):
	
		# gather all @(...)@
		pattern = "(@([^@]+)@)"
		
		p = re.compile(pattern)
		
		mlist = p.findall(ss)
		
		if len(mlist) == 0:
			return ss
		
		for mi in mlist:
			macro = mi[0]
			define = mi[1]
			
			if self.Has(define):
				ss = self.PerformSub(ss, macro, self.Get(define))
	
		return ss