def eval(x, env):
"Evaluate an expression in an environment."
if isa(x, Symbol): # variable reference
return env[x]
elif isa(x, list): # (proc exp*)
proc = eval(x[0], env)
if hasattr(proc, '__call__'):
return proc(env,*x[1:])
raise ValueError("%s = %s is not a procedure" % (to_string(x[0]),to_string(proc)))
return x
def eval(x, env):
"Evaluate an expression in an environment."
if isa(x, Symbol): # variable reference
return env[x]
elif isa(x, list): # (proc exp*)
proc = eval(x[0], env)
if hasattr(proc, '__call__'):
return proc(env,*x[1:])
raise ValueError("%s = %s is not a procedure" % (to_string(x[0]),to_string(proc)))
return x
def repl(prompt='vau> '):
try:
while True:
full_line = raw_input(prompt)
rps = full_line.count("(")-full_line.count(")")
while rps != 0 or full_line == "":
line = raw_input(">\t")
full_line += line
rps += line.count("(")-line.count(")")
try:
tokens = tokenize(full_line)
while len(tokens) > 0:
val = eval(parse(tokens),global_env)
if val is not None: print to_string(val)
except ValueError as e:
print e.message
except (KeyboardInterrupt, SystemExit):
pass
except:
print "\nFatal Error\n"
traceback.print_exc()
def repl(prompt='vau> '):
try:
while True:
full_line = raw_input(prompt)
rps = full_line.count("(") - full_line.count(")")
while rps != 0 or full_line == "":
line = raw_input(">\t")
full_line += line
rps += line.count("(") - line.count(")")
try:
tokens = tokenize(full_line)
while len(tokens) > 0:
tree = parse(tokens)
if tree is not None:
val = eval(tree, global_env)
if val is not None: print to_string(val)
except ValueError as e:
print e.message
except (KeyboardInterrupt, SystemExit):
pass
except:
print "\nFatal Error\n"
traceback.print_exc()
def vprint(v, e):
val = eval(e, v)
print to_string(val)
return val
def vprint(v, e):
val = eval(e, v)
print to_string(val)
return val
