def cdr(args, env):
if len(args) != 1:
raise Exception("cdr: arity mismatch!")
p = lispEval(args[0], env)
if type(p) != pair:
raise Exception("cdr: expected pair, got " + type(p).__name__)
else:
return lispEval(p.get(1), env)
def greater(args, env):
if len(args) < 2:
raise Exception(">: arity mismatch!")
first = lispEval(args[0], env)
for arg in args[1:]:
if (lispEval(arg, env) >= first):
return False
return True
def isList(args, env):
if len(args) != 1:
raise Exception("list?: arity mismatch!")
else:
if type(lispEval(args[0], env)) == pair:
next = cdr([lispEval(args[0], env)], env)
return isList([next], env)
else:
if lispEval(args[0], env) == None:
return True
return False
def equal(args, env):
if not args:
raise Exception("=: arity mismatch!")
prev = lispEval(args[0], env)
for arg in args[1:]:
if (lispEval(arg, env) != prev):
return False
prev = lispEval(arg, env)
return True
def div(args, env):
if len(args) == 1:
return 1 / lispEval(args[0], env)
elif len(args) > 0:
quot = lispEval(args[0], env)
else:
raise Exception("/: arity mismatch!")
for arg in args[1:]:
quot /= lispEval(arg, env)
return quot
def minus(args, env):
if len(args) == 1:
return -lispEval(args[0], env)
elif len(args) > 0:
sum = lispEval(args[0], env)
else:
raise Exception("-: arity mismatch!")
for arg in args[1:]:
sum -= lispEval(arg, env)
return sum
def evaluate(args, env):
if len(args) != 1:
raise Exception("eval: arity mismatch!")
else:
arg = lispEval(args[0], env)
if isConstant(arg):
return arg
# this method is cancerous but it works
try:
return lispEval(arg, env)
except:
return lispEval(parse(preparse(arg)), env)
def isPair(args, env):
if len(args) != 1:
raise Exception("pair?: arity mismatch!")
else:
if type(lispEval(args[0], env)) == pair:
return True
else:
return False
def mod(args, env):
if len(args) != 2:
raise Exception("modulo: arity mismatch!")
return lispEval(args[0], env) % lispEval(args[1], env)
def mult(args, env):
prod = 1
for arg in args:
prod *= lispEval(arg, env)
return prod
def plus(args, env):
sum = 0
for arg in args:
sum += lispEval(arg, env)
return sum
def isNumber(args, env):
if len(args) != 1:
raise Exception("number?: arity mismatch!")
else:
arg = lispEval(args[0], env)
return isInt(arg) or isFloat(arg) or (type(arg) in [float, int])
def expt(args, env):
if len(args) != 2:
raise Exception("exp: arity mismatch!")
return lispEval(args[0], env)**lispEval(args[1], env)
def rand(args, env):
if len(args) != 2:
raise Exception("random: arity mismatch!")
return randint(lispEval(args[0], env), lispEval(args[1], env))
def cons(args, env):
if len(args) != 2:
raise Exception("cons: arity mismatch!")
else:
return pair(lispEval(args[0], env), lispEval(args[1], env))