from cTranslator import CTranslator
from dfareg import Regexp, CallGraph

class GREPTranslateExeption(Exception):
    pass

class GREPTranslator(CTranslator):
    """GREPTranslator
    >>> string = \"(A|B)*C\"
    >>> reg = Regexp(string)
    >>> dfacg = CallGraph(reg.dfa)
    >>> tje = GREPTranslator(string, dfacg)
    >>> tje.translate()
    """

    def __init__(self, regexp, cg):
        if cg.type == "NFA": raise GREPTranslateExeption("can't translate grep from NFA")
        CTranslator.__init__(self, regexp, cg)
        self.funType = 'int '
        self.callType = 'return '
        self.breakStatement = ''

    def emit_accept_state(self):
        self.emit ("""
%saccept(char* s) {
\treturn 1;
}\n""" % self.funType)

    def emit_reject_state(self):
        self.emit ("""
%sreject(char* s) {
\treturn 0;
}\n""" % self.funType)

    def emit_initialization(self):
        self.emit("#include <stdio.h>\n")
        self.emit("#include <stdlib.h>\n")
        self.emit("#include <string.h>\n\n")
        self.emit("#define BUFSIZE 1024\n\n")
        for state in self.cg.map.iterkeys():
            self.emit(self.funType + self.modify_state_name(state) + "(char* s);\n")
        self.emit(self.funType + 'accept(char* s);\n')
        self.emit(self.funType + 'reject(char* s);\n')

    def emit_driver(self):
        self.emit("""
int match(char *text) {
  do {
    if (%s(text))
      return 1;
  } while (*text++ != '\\0');
  return 0;
}\n\n""" % (self.modify_state_name(self.cg.start)))
        self.emit(open("template/grep.template", "r").read())
        self.emit("\n")

    def emit_state(self, cur_state, transition):
        self.emit(self.funType + self.modify_state_name(cur_state) + "(char* s) {\n")
        if cur_state in self.cg.accepts:
            self.emit("\treturn accept(s);\n")
        else:
            if transition:
                if self.cg.type == "DFA":
                    self.emit_switch(transition, default="reject")
                else:
                    self.emit_switch(transition)
        self.emit("}\n\n")

def test():
    import doctest
    doctest.testmod()

if __name__ == '__main__': test()