def eval(self, t, env):
#if variable definition
if t.getCdr().getCar().isSymbol():
env.define(
t.getCdr().getCar(),
Cons(t.getCdr().getCdr().getCar().eval(env),
Nil.getInstance()))
#If definition is for a closure
elif t.getCdr().getCar().isPair():
env.define(t.getCdr().getCar().getCar(),
Cons(Closure(t.getCdr(), env), Nil.getInstance()))
return Nil.getInstance()
def eval(self, exp, env):
key = exp.getCdr().getCar()
val = exp.getCdr().getCdr().getCar()
# if defining a variable
if key.isSymbol():
env.define(key, val)
# if defining a function
else:
func = Closure(
Cons(exp.getCdr().getCar().getCdr(),
exp.getCdr().getCdr()), env)
env.define(key.getCar(), func)
return StrLit("no values returned")
def eval(self, exp, env):
return Closure(exp.getCdr(), env, trimmed=True)
def eval(self, exp, env):
return Closure(exp, env)
from Special import Special
from Util import Util
if __name__ == "__main__":
# Initialization file with Scheme definitions of built-in functions
ini_file = "ini.scm"
prompt = "> "
# Create scanner that reads from standard input
scanner = Scanner(sys.stdin)
util = Util()
Cons.setUtil(util)
BuiltIn.setUtil(util)
Closure.setUtil(util)
Special.setUtil(util)
if (len(sys.argv) > 2 or (len(sys.argv) == 2 and sys.argv[1] != "-d")):
sys.stderr.write("Usage: python3 SPP.py [-d]\n")
sys.stderr.flush()
sys.exit(2)
# If command line option -d is provided, debug the scanner.
if len(sys.argv) == 2 and sys.argv[1] == "-d":
tok = scanner.getNextToken()
while tok != None:
tt = tok.getType()
sys.stdout.write(str(tt))
if tt == TokenType.INT: