def simplify(expr, env):
if isinstance(expr, sym):
try:
return env[expr]
except KeyError:
raise NameError("symbol %s is not defined"%(expr,))
elif isinstance(expr, hack):
return simplify(expr[0], expr[1])
elif isinstance(expr, linked_list):
f = expr[0]
if isinstance(f, jcli_parser.syntax):
f=f.value
if f == sym('define'):
if len(expr) != 3:
raise SyntaxError("bad syntax in define")
env[expr[1].value] = eval_ast(expr[2], env)
elif f == sym('lambda'):
if len(expr) != 3:
raise SyntaxError("bad syntax in lambda")
arg_names = expr[1].value
body = expr[2]
def function(*args):
c = closure(env)
if len(arg_names) != len(args):
raise TypeError(
'function expected %s arguments, got %s'
%(len(arg_names), len(args)))
for arg_name, arg in zip(arg_names, args):
c[arg_name.value] = arg
out = hack((body.value, c))
return out
return function
elif f == sym('if'):
if len(expr) != 4:
raise SyntaxError("bad syntax in if")
if eval_ast(expr[1], env):
return hack((expr[2].value, env))
else:
return hack((expr[3].value, env))
elif f == sym('quote'):
if len(expr) != 2:
raise SyntaxError("bad syntax in quote")
return quote(jcli_parser.syntax_to_list(expr[1]))
elif f == sym('begin'):
out = None
for sub_expr in cdr(expr):
out = eval_ast(sub_expr, env)
return out
else:
return apply(
eval_ast(expr[0], env),
map(lambda x: eval_ast(x, env), cdr(expr)))
else:
return expr
jcli_globals = {
sym('eval'): lambda x: (
eval_ast(x.value, closure(jcli_globals))
if isinstance(x, quote)
else x),
sym('+'): operator.add,
sym('-'): operator.sub,
sym('*'): operator.mul,
# sym('/'): operator.div,
sym('='): operator.eq,
sym('or'): lambda x,y: x or y,
sym('and'): lambda x,y: x and y,
sym('not'): lambda x: not x,
sym('cons'): lambda x,y: cons(x, y.value),
sym('car'): lambda x: car(x.value),
sym('cdr'): lambda x: cdr(x.value),}
def eval(string, bindings=None, builtins=None):
if builtins is None:
builtins = jcli_globals
if bindings is None:
bindings = closure(builtins)
else:
bindings = {sym(k): bindings[k] for k in bindings.keys()}
bindings.update(builtins)
asts = jcli_parser.parse(string)
return list(map(lambda ast: eval_ast(ast, bindings), asts))
def eval_ast(ast, env):
try:
