# parser definition for the Jackal compiler
# Author: Josh Holtrop
# Date: 2010-09-14

from nodes import *

###########################################################################
# Lexer Definition                                                        #
###########################################################################
reserved = {
        # control
        'if':       'IF',
        'else':     'ELSE',
        'while':    'WHILE',
        'return':   'RETURN',

        # types
        'byte':     'BYTE',
        'short':    'SHORT',
        'int':      'INT',
        'long':     'LONG',
        'string':   'STRING',
        'class':    'CLASS',
        }

tokens = [
        # identifiers
        'ID',

        # literals
        'NUMBER',

        # assignment
        'ASSIGN',

        # operators
        'EQUALS',
        'DEQUALS',
        'TIMES',
        'DIVIDE',
        'PLUS',
        'MINUS',
        'LESS',
        'GREATER',

        # punctuation
        'LPAREN',
        'RPAREN',
        'LCURLY',
        'RCURLY',
        'LBRACKET',
        'RBRACKET',
        'DOT',
        'COLON',
        'SEMICOLON',
        'COMMA',
        ] + list(reserved.values())

t_ASSIGN    = r':='

t_NUMBER    = r'[0-9]+'

t_EQUALS    = r'='
t_DEQUALS   = r'=='
t_TIMES     = r'\*'
t_DIVIDE    = r'/'
t_PLUS      = r'\+'
t_MINUS     = r'-'
t_LESS      = r'<'
t_GREATER   = r'>'

t_LPAREN    = r'\('
t_RPAREN    = r'\)'
t_LCURLY    = r'\{'
t_RCURLY    = r'\}'
t_LBRACKET  = r'\['
t_RBRACKET  = r'\]'
t_DOT       = r'\.'
t_COLON     = r':'
t_SEMICOLON = r';'
t_COMMA     = r','

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

def t_newline(t):
    r'\n'
    t.lexer.lineno += 1

t_ignore    = " \t"


###########################################################################
# Parser Definition                                                       #
###########################################################################

precedence = (
        ('right',   'ASSIGN'),
        ('left',    'PLUS', 'MINUS'),
        ('left',    'TIMES', 'DIVIDE'),
        )

def p_module(p):
    '''module : classes'''
    p[0] = ModuleNode(p[1])

def p_classes_empty(p):
    '''classes : empty'''
    p[0] = []

def p_classes_class(p):
    '''classes : class classes'''
    p[0] = [p[1]] + p[2]

def p_class(p):
    '''class : CLASS ID LCURLY class_items RCURLY'''
    p[0] = ClassNode(p[2], p[4])

def p_class_items_empty(p):
    '''class_items : empty'''
    p[0] = []

def p_class_items_item(p):
    '''class_items : class_item class_items'''
    p[0] = [p[1]] + p[2]

def p_class_item(p):
    '''class_item : varspec
                  | function'''
    p[0] = p[1]

def p_varspec(p):
    '''varspec : ID COLON type SEMICOLON'''
    p[0] = VarspecNode(p[1], p[3])

def p_function(p):
    '''function : ID LPAREN param_list RPAREN COLON type LCURLY function_items RCURLY'''
    p[0] = FunctionNode(p[1], p[3], p[6], p[8])

def p_param_list_empty(p):
    '''param_list : empty'''
    p[0] = []

def p_param_list_param(p):
    '''param_list : param param_list_more'''
    p[0] = [p[1]] + p[2]

def p_param_list_more_empty(p):
    '''param_list_more : empty'''
    p[0] = []

def p_param_list_more_param(p):
    '''param_list_more : COMMA param param_list_more'''
    p[0] = [p[2]] + p[3]

def p_param(p):
    '''param : type ID'''
    p[0] = ParamNode(p[2], p[1])

def p_function_items_empty(p):
    '''function_items : empty'''
    p[0] = []

def p_function_items_item(p):
    '''function_items : function_item function_items'''
    p[0] = [p[1]] + p[2]

def p_function_item(p):
    '''function_item : function
                     | statement'''
    p[0] = p[1]

def p_statement_varspec(p):
    '''statement : varspec'''
    p[0] = p[1]

def p_statement_expression(p):
    '''statement : expression SEMICOLON'''
    p[0] = p[1]

def p_statement_block(p):
    '''statement : LCURLY function_items RCURLY'''
    p[0] = BlockNode(p[2])

def p_statement_return(p):
    '''statement : RETURN expression SEMICOLON'''
    p[0] = ReturnNode(p[2])

def p_type(p):
    '''type : BYTE
            | SHORT
            | INT
            | LONG
            | STRING
            | ID'''
    p[0] = TypeNode(p[1])

def p_expression_id(p):
    '''expression : ID'''
    p[0] = p[1]

def p_expression_literal(p):
    '''expression : NUMBER'''
    p[0] = p[1]

def p_expression_binop(p):
    '''expression : expression binop expression'''
    p[0] = BinOpNode(p[2], p[1], p[3])

def p_binop(p):
    '''binop : TIMES
             | DIVIDE
             | PLUS
             | MINUS
             | ASSIGN'''
    p[0] = p[1]

def p_empty(p):
    '''empty :'''