import ply.lex as lex

class Lexer(object):
    def __init__(self):
        self.reserved = {
                'C': 'C',

                # types
                'char': 'CHAR',
                'short': 'SHORT',
                'int': 'INT',
                'long': 'LONG',

                # control
                'if': 'IF',
                'else': 'ELSE',
                'while': 'WHILE',
                'for': 'FOR',
                'return': 'RETURN',
                }

        self.tokens = [
                'LPAREN',
                'RPAREN',
                'LBRACKET',
                'RBRACKET',
                'LCURLY',
                'RCURLY',
                'SEMICOLON',
                'STRING',
                'ID',
                ] + list(self.reserved.values())

        self.states = (
                ('string', 'exclusive'),
                )

        self.t_LPAREN = r'\('
        self.t_RPAREN = r'\)'
        self.t_LBRACKET = r'\['
        self.t_RBRACKET = r'\]'
        self.t_LCURLY = r'\{'
        self.t_RCURLY = r'\}'
        self.t_SEMICOLON = r';'

        self.t_ignore = ' \t\r'

        self.t_string_ignore = ''

        self.lexer = lex.lex(module = self)

    def t_ID(self, t):
        r'[a-zA-Z_][a-zA-Z_0-9]*'
        t.type = self.reserved.get(t.value, 'ID')
        return t

    def t_STRING(self, t):
        r'\"'
        self.str_buildup = ''
        t.lexer.begin('string')

    def t_string_1(self, t):
        r'[^\\\n\"]'
        self.str_buildup += t.value

    def t_string_2(self, t):
        r'\\[^\n]'
        c = {
                't': '\t',
                'r': '\r',
                'n': '\n',
                'f': '\f',
                'b': '\b',
                'v': '\v',
            }.get(t.value[1], t.value[1])
        self.str_buildup += c

    def t_string_3(self, t):
        r'\"'
        t.type = 'STRING'
        t.value = self.str_buildup
        t.lexer.begin('INITIAL')
        return t

    def t_newline(self, t):
        r'\n+'
        t.lexer.lineno += len(t.value)
        return None

    def t_ANY_error(self, t):
        print 'Illegal character "%s"' % t.value[0]
        t.lexer.skip(1)

    def input(self, *args):
        self.lexer.input(*args)

    def token(self, *args):
        return self.lexer.token(*args)