def add_production()

in functions/source/KeyGen/pycparser/ply/yacc.py [0:0]

• 60 lines of code
• 25 McCabe index (conditional complexity)

    def add_production(self, prodname, syms, func=None, file='', line=0):

        if prodname in self.Terminals:
            raise GrammarError('%s:%d: Illegal rule name %r. Already defined as a token' % (file, line, prodname))
        if prodname == 'error':
            raise GrammarError('%s:%d: Illegal rule name %r. error is a reserved word' % (file, line, prodname))
        if not _is_identifier.match(prodname):
            raise GrammarError('%s:%d: Illegal rule name %r' % (file, line, prodname))

        # Look for literal tokens
        for n, s in enumerate(syms):
            if s[0] in "'\"":
                try:
                    c = eval(s)
                    if (len(c) > 1):
                        raise GrammarError('%s:%d: Literal token %s in rule %r may only be a single character' %
                                           (file, line, s, prodname))
                    if c not in self.Terminals:
                        self.Terminals[c] = []
                    syms[n] = c
                    continue
                except SyntaxError:
                    pass
            if not _is_identifier.match(s) and s != '%prec':
                raise GrammarError('%s:%d: Illegal name %r in rule %r' % (file, line, s, prodname))

        # Determine the precedence level
        if '%prec' in syms:
            if syms[-1] == '%prec':
                raise GrammarError('%s:%d: Syntax error. Nothing follows %%prec' % (file, line))
            if syms[-2] != '%prec':
                raise GrammarError('%s:%d: Syntax error. %%prec can only appear at the end of a grammar rule' %
                                   (file, line))
            precname = syms[-1]
            prodprec = self.Precedence.get(precname)
            if not prodprec:
                raise GrammarError('%s:%d: Nothing known about the precedence of %r' % (file, line, precname))
            else:
                self.UsedPrecedence.add(precname)
            del syms[-2:]     # Drop %prec from the rule
        else:
            # If no %prec, precedence is determined by the rightmost terminal symbol
            precname = rightmost_terminal(syms, self.Terminals)
            prodprec = self.Precedence.get(precname, ('right', 0))

        # See if the rule is already in the rulemap
        map = '%s -> %s' % (prodname, syms)
        if map in self.Prodmap:
            m = self.Prodmap[map]
            raise GrammarError('%s:%d: Duplicate rule %s. ' % (file, line, m) +
                               'Previous definition at %s:%d' % (m.file, m.line))

        # From this point on, everything is valid.  Create a new Production instance
        pnumber  = len(self.Productions)
        if prodname not in self.Nonterminals:
            self.Nonterminals[prodname] = []

        # Add the production number to Terminals and Nonterminals
        for t in syms:
            if t in self.Terminals:
                self.Terminals[t].append(pnumber)
            else:
                if t not in self.Nonterminals:
                    self.Nonterminals[t] = []
                self.Nonterminals[t].append(pnumber)

        # Create a production and add it to the list of productions
        p = Production(pnumber, prodname, syms, prodprec, func, file, line)
        self.Productions.append(p)
        self.Prodmap[map] = p

        # Add to the global productions list
        try:
            self.Prodnames[prodname].append(p)
        except KeyError:
            self.Prodnames[prodname] = [p]