def if_alternative(exp):
if is_null(cdddr(exp)):
return Symbol("the-unspecified-value")
else:
return cadddr(exp)
def make_begin(actions):
return cons(Symbol("begin"), actions)
def is_if(exp):
return is_tagged_list(exp, Symbol("if"))
def make_lambda(parameters, body):
return cons(
Symbol("lambda"),
cons(parameters,
begin_actions(body) if is_begin(body) else (body, )),
)
def is_begin(exp):
return is_tagged_list(exp, Symbol("begin"))
def is_definition(exp):
return is_tagged_list(exp, Symbol("define"))
def is_lambda(exp):
return is_tagged_list(exp, Symbol("lambda"))
def is_assignment(exp):
return is_tagged_list(exp, Symbol("set!"))
def is_undoable_assignment(exp):
return is_tagged_list(exp, Symbol("maybe-set!"))
def make_if(pred, conseq, alternative):
return Symbol("if"), pred, conseq, alternative
def is_cond(exp):
return is_tagged_list(exp, Symbol("cond"))
def is_let(exp):
return is_tagged_list(exp, Symbol("let"))
def is_else_clause(clause):
return cond_clause_predicate(clause) == Symbol("else")
THE_GLOBAL_ENVIRONMENT = "not initialized"
def initialize_repl():
global THE_GLOBAL_ENVIRONMENT
THE_GLOBAL_ENVIRONMENT = make_initial_environment()
def check_repl_initialized():
if THE_GLOBAL_ENVIRONMENT == "not initialized":
raise RuntimeError("Interpreter not initialized. Run init() first.")
if __name__ == "__main__":
a = Symbol("a")
b = Symbol("b")
c = Symbol("c")
print((a, b, c))
print(car((1, 2, 3)), cdr((1, 2, 3)))
x = cons(1, (2, 3, 4))
print(x)
print(car(x), cdr(x), cdr(cdr(x)))
quote = Symbol("quote")
x = Symbol("x")
begin = Symbol("begin")
# print(g.eval(((Symbol('lambda'), (x,), x), 42), ()))