def desugar_arith(sexpr):
if sexpr.length() == 1:
if sexpr.first().repr() == "+" or sexpr.first.repr() == "-":
return v.Number(0)
else:
return v.Number(1)
elif sexpr.length() == 2:
return desugar(sexpr.rest().first())
# Recursive case
elif sexpr.length() > 2:
return e.Application(
desugar(sexpr.first()), desugar(sexpr.second()),
desugar(s.Cons(sexpr.first(), sexpr.right.rest())))
else:
salt()
def desugar(sexpr):
if isinstance(sexpr, s.Atom):
return desugar_atom(sexpr)
if isinstance(sexpr, s.Nil):
return e.Application(v.Number(0)) # invalid
if isinstance(sexpr, s.Atom):
return desugar_atom(sexpr)
action = sexpr.first().repr()
if action in antirecipies:
return antirecipies[action](sexpr)
else:
return desugar_generic_app(sexpr)
def desugar_atom(sexpr):
if not isinstance(sexpr, s.Atom):
desugar(sexpr)
if is_number(sexpr.repr()):
return v.Number(float(sexpr.repr()))
elif sexpr.repr() in v.Prims:
return v.Primitive(sexpr.repr())
# Sugarbools
elif sexpr.repr() == "#t":
return v.Bool(1)
elif sexpr.repr() == "#f":
return v.Bool(0)
elif sexpr.repr() == "unit":
return v.Unit()
# parser doesn't support spaces and I don't want to rearchitect it so this will do:
elif sexpr.repr() == "#S":
return v.String("\" \"")
elif sexpr.repr()[0] == "\"" and sexpr.repr()[-1] == "\"":
return v.String(sexpr.repr())
# Must be an id then
else:
return v.ID(sexpr.repr())
def __call__(self):
return v.Number(self.left.value / self.right.value)