[pypy-svn] r55904 - in pypy/branch/jit-hotpath/pypy/lang/automata: . test

[fijal at codespeak.net]

Author: fijal
Date: Mon Jun 16 22:57:03 2008
New Revision: 55904

Added:
   pypy/branch/jit-hotpath/pypy/lang/automata/nfa.py   (contents, props changed)
   pypy/branch/jit-hotpath/pypy/lang/automata/test/test_nfa.py   (contents, props changed)
Log:
Mostly for fun, include nfa engine


Added: pypy/branch/jit-hotpath/pypy/lang/automata/nfa.py
==============================================================================
--- (empty file)
+++ pypy/branch/jit-hotpath/pypy/lang/automata/nfa.py	Mon Jun 16 22:57:03 2008
@@ -0,0 +1,76 @@
+
+class NFA(object):
+    def __init__(self, num_states=0, transitions=None, final_states=None):
+        self.num_states = 0
+        self.transitions = {}
+        self.final_states = {}
+
+    def add_state(self, final=False):
+        state = self.num_states
+        self.num_states += 1
+        if final:
+            self.final_states[state] = None
+        return self.num_states - 1
+
+    def add_transition(self, state, input, next_state):
+        if (state, input) in self.transitions:
+            self.transitions[state, input].append(next_state)
+        else:
+            self.transitions[state, input] = [next_state]
+
+    def get_transitions(self, state, input):
+        return self.transitions[state, input]
+
+    def get_language(self):
+        all_chars = {}
+        for state, input in self.transitions:
+            all_chars[input] = None
+        return all_chars
+
+    def __repr__(self):
+        from pprint import pformat
+        return "NFA%s" % (pformat(
+            (self.num_states, self.transitions, self.final_states)))
+
+def getautomaton():
+    a = NFA()
+    s0 = a.add_state()
+    s1 = a.add_state()
+    s2 = a.add_state(final=True)
+    a.add_transition(s0, "a", s0)
+    a.add_transition(s0, "c", s1) 
+    a.add_transition(s0, "c", s0)
+    a.add_transition(s0, "b", s2) 
+    a.add_transition(s1, "b", s2)
+    return a
+
+def recognize(automaton, s):
+    " a simple recognizer"
+    state = 0
+    stack = []
+    i = 0
+    while True:
+        char = s[i]
+        try:
+            states = automaton.get_transitions(state, char)
+        except KeyError:
+            if len(stack) == 0:
+                return False
+            i, state = stack.pop()
+        else:
+            if len(states) == 1:
+                i += 1
+                state = states[0]
+            else:
+                for next_state in states[1:]:
+                    stack.append((i + 1, next_state))
+                i += 1
+                state = states[0]
+        while i == len(s):
+            if state in automaton.final_states:
+                return True
+            if len(stack) == 0:
+                return False
+            i, state = stack.pop()
+
+    return state in automaton.final_states

Added: pypy/branch/jit-hotpath/pypy/lang/automata/test/test_nfa.py
==============================================================================
--- (empty file)
+++ pypy/branch/jit-hotpath/pypy/lang/automata/test/test_nfa.py	Mon Jun 16 22:57:03 2008
@@ -0,0 +1,49 @@
+import py
+from pypy import conftest
+
+from pypy.rpython.test.test_llinterp import interpret
+
+from pypy.lang.automata.nfa import *
+
+def rundfa():
+    a = getautomaton()
+    assert 'a' in a.get_language()
+    assert 'b' in a.get_language()
+    assert 'c' in a.get_language()
+    assert 'd' not in a.get_language()
+
+    assert recognize(a, "aaaaaaaaaab")
+    assert recognize(a, "b")
+    assert recognize(a, "aaaacb")
+    
+    assert not recognize(a, "a")
+    assert not recognize(a, "xyza")
+
+    assert recognize(a, "acccb")
+
+def test_nfa_simple():
+    rundfa()
+
+def test_nfa_interp():
+    interpret(rundfa, [])
+
+def test_nfa_compiledummy():
+    py.test.skip("not working")
+    def main(gets):
+        a = getautomaton()
+        dfatable, final_states = convertdfa(a)
+        s = ["aaaaaaaaaab", "aaaa"][gets]
+        return recognizetable(dfatable, s, final_states)
+    assert interpret(main, [0])
+    assert not interpret(main, [1])
+
+def test_nfa_compiledummy2():
+    py.test.skip("not working")
+    def main(gets):
+        a = getautomaton()
+        alltrans, final_states = convertagain(a)
+        s = ["aaaaaaaaaab", "aaaa"][gets]
+        return recognizeparts(alltrans, final_states, s)
+    assert interpret(main, [0])
+    assert not interpret(main, [1])
+