lis.py: added 'define' procedure short form

This commit is contained in:
Luciano Ramalho 2021-06-09 23:27:42 -03:00
parent 0cbb0c557c
commit e5173fb72b

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@ -151,12 +151,12 @@ def evaluate(x: Expression, env: Environment) -> Any:
case ['if', test, conseq, alt]: # (if test conseq alt)
exp = conseq if evaluate(test, env) else alt
return evaluate(exp, env)
case ['lambda', parms, body]: # (lambda (parm...) body)
return Procedure(parms, body, env)
case ['define', Symbol(var), exp]: # (define var exp)
env[var] = evaluate(exp, env)
case ['define', [name, *parms], body]: # (define (fun parm...) body)
env[name] = Procedure(parms, body, env)
case ['lambda', parms, body]: # (lambda (parm...) body)
return Procedure(parms, body, env)
case [op, *args]: # (proc arg...)
proc = evaluate(op, env)
values = (evaluate(arg, env) for arg in args)