from ply.lex import lex
from ply.yacc import yacc
from decimal import *
setcontext(Context(prec=2000,rounding=ROUND_HALF_DOWN))
factorial=[1]
fac=Decimal('1')
for i in range(2,1000):
    fac*=Decimal(i)
    factorial.append(fac)

def sin(s):
    sin=Decimal(s)
    s=Decimal(s)
    for i in range(5,1000,4):
        sin+=(Decimal((s**Decimal(i)))/Decimal(factorial[i-1]))
    for i in range(3,1000,4):
        sin-=(Decimal((s**Decimal(i)))/Decimal(factorial[i-1]))
    return sin

def cos(s):
    cos=Decimal('1')
    s=Decimal(s)
    for i in range(4,1000,4):
        cos+=(Decimal((s**Decimal(i)))/Decimal(factorial[i-1]))
    for i in range(2,1000,4):
        cos-=(Decimal((s**Decimal(i)))/Decimal(factorial[i-1]))
    return cos

def tan(s):
    return sin(s)/cos(s)

tokens=['NUM','PLUS','MINUS','TIMES','DIVIDE','LPAREN','RPAREN','SIN','COS','TAN']
#tokens=['NUM','PLUS','MINUS','TIMES','DIVIDE','LPAREN','RPAREN', 'SIN']

t_ignore=' \t\n'

t_PLUS=r'\+'
t_MINUS=r'\-'
t_TIMES=r'\*'
t_DIVIDE=r'/'
t_LPAREN=r'\('
t_RPAREN=r'\)'
t_SIN=r'sin'
t_COS=r'cos'
t_TAN=r'tan'

def t_NUM(t):
    r'\d+(\.\d+)?'

    t.value=Decimal(t.value)
    return t

def t_SIN(t):
    r'sin\((\d+(\.\d+)?)\)'
    t.value=sin(Decimal(t))
    return t

def t_COS(t):
    r'cos\((\d+(\.\d+)?)\)'
    t.value=cos(Decimal(t))
    return t

def t_TAN(t):
    r'tan\((\d+(\.\d+)?)\)'
    t.value=tan(Decimal(t))
    return t

def t_error(t):
    print('Bad Character: {!r}'.format(t.value[0]))
    t.lexer.skip(1)

lexer=lex()

def p_expr(p):
    '''
    expr : expr PLUS term
         | expr MINUS term
    '''
    if p[2]=='+':
        p[0]=p[1]+p[3]
    elif p[2]=='-':
        p[0]=p[1]-p[3]

def p_expr_term(p):
  '''
  expr : term
  '''
  p[0]=p[1]

def p_term(p):
  '''
  term : term TIMES factor
       | term DIVIDE factor
  '''
  if p[2]=='*':
    p[0]=p[1]*p[3]
  elif p[2]=='/':
    p[0]=p[1]/p[3]

def p_term_factor(p):
  '''
  term : factor
  '''
  p[0]=p[1]

def p_factor(p):
  '''
  factor : NUM
  '''
  p[0]=p[1]

'''
def p_factor(p):

    factor : SIN
           | COS
           | TAN


    if p[0]=='sin':
        p[0]=Decimal(sin(Decimal(p[1])))
    elif p[0]=='cos':
        p[0]=Decimal(cos(Decimal(p[1])))
    elif p[0]=='tan':
        p[0]=Decimal(sin(Decimal(p[1]))/cos(Decimal(p[1])))

    p[0]=p[1]
'''

def p_factor_group(p):
  '''
  factor : LPAREN expr RPAREN
  '''
  p[0]=p[2]

def p_error(p):
  if p:
      print("Syntax error at '%s'" % p.value)
  else:
      print("Syntax error at EOF")

#if __name__ == '__main__':
parser=yacc()