Mercurial > lcfOS

comparison python/pyyacc.py @ 240:6259856841a0

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Remove project
author Windel Bouwman
date Mon, 22 Jul 2013 22:37:33 +0200
parents 494828a7adf1
children e84047f29c78
comparison
equal deleted inserted replaced
239:63bb40758066 240:6259856841a0
1 """ 1 """
2 Parser generator script 2 Parser generator script
3 """ 3 """
4 4
5 import shelve
6 import hashlib 5 import hashlib
7 from ppci import Token 6 from ppci import Token
8 7
9 EPS = 'EPS' 8 EPS = 'EPS'
10 EOF = 'EOF' 9 EOF = 'EOF'
168 signature = m.hexdigest() 167 signature = m.hexdigest()
169 168
170 def genParser(self): 169 def genParser(self):
171 """ Generates a parser from the grammar (using a caching algorithm) """ 170 """ Generates a parser from the grammar (using a caching algorithm) """
172 signature = self.getSignature() 171 signature = self.getSignature()
173 cache = shelve.open('__grammar_cache__.shelve') 172 action_table, goto_table = self.doGenerate()
174 # TODO: fix caching.
175 if ('signature1' in cache) and cache['signature'] == signature:
176 goto_table = cache['goto_table']
177 action_table = cache['action_table']
178 else:
179 action_table, goto_table = self.doGenerate()
180 cache['goto_table'] = goto_table
181 cache['action_table'] = action_table
182 cache['signature'] = signature
183 cache.close()
184 p = LRParser(action_table, goto_table, self.start_symbol) 173 p = LRParser(action_table, goto_table, self.start_symbol)
185 p.grammar = self 174 p.grammar = self
186 return p 175 return p
187 176
188 def doGenerate(self): 177 def doGenerate(self):