def execute(self, scope, sexp):
if types.is_atomic(sexp):
return self.eval(scope, sexp)
if types.is_nil(sexp):
return sexp
func = self.eval(scope, sexp.car)
args = list(sexp.cdr)
if types.is_primitive(func):
return self.invoke(scope, func, args)
if types.is_macro(func):
return self.eval(scope, self.invoke(scope, func, args))
if types.is_function(func):
return self.invoke(scope, func, (self.eval(scope, arg) for arg in args))
raise LispException("%s is not callable" % repr(func), sexp)
def invoke(self, scope, func, args, tailrec = False):
args = list(args)
if types.is_primitive(func):
return func.invoke(scope, args)
try:
rest = list((i.value for i in func.sig)).index("&")
except ValueError:
rest = -1
if len(args) != len(func.sig):
raise LispException("%s takes %d arguments, %d given" %
(types.type_name(func),
len(func.sig), len(args)))
else:
if len(args) < rest:
raise LispException("%s takes at least %d arguments, %d given" %
(types.type_name(func), rest, len(args)))
closure = scope if tailrec else Scope(func, func.scope)
for i in xrange(len(args)):
if func.sig[i].value == "&":
closure.define(func.sig[rest+1].value,
types.mklist(args[rest:]))
rest = -1
break
else:
closure.define(func.sig[i].value, args[i])
if rest >= 0:
closure.define(func.sig[rest+1].value, types.nil)
rv = types.nil
for sexp in func.value:
rv = self.execute(closure, sexp)
return rv
