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package hm
import "testing"
var unifyTests = []struct {
name string
a Type
b Type
subs Subs
err bool // does it error?
}{
{"a ~ a (recursive unification)", TypeVariable('a'), TypeVariable('a'), nil, true},
{"a ~ b", TypeVariable('a'), TypeVariable('b'), mSubs{'a': TypeVariable('b')}, false},
{"a ~ proton", TypeVariable('a'), proton, mSubs{'a': proton}, false},
{"proton ~ a", proton, TypeVariable('a'), mSubs{'a': proton}, false},
// typeconst ~ typeconst
{"proton ~ proton", proton, proton, nil, false},
{"proton ~ neutron", proton, neutron, nil, true},
{"List a ~ List proton", list{TypeVariable('a')}, list{proton}, mSubs{'a': proton}, false},
// function types
{"List a → List a ~ List proton → List proton",
NewFnType(list{TypeVariable('a')}, list{TypeVariable('a')}),
NewFnType(list{proton}, list{proton}),
mSubs{'a': proton}, false},
{"List proton → List proton ~ List a → List a",
NewFnType(list{proton}, list{proton}),
NewFnType(list{TypeVariable('a')}, list{TypeVariable('a')}),
mSubs{'a': proton}, false},
{"List a → a ~ List proton → proton",
NewFnType(list{TypeVariable('a')}, TypeVariable('a')),
NewFnType(list{proton}, proton),
mSubs{'a': proton}, false},
{"List proton → proton ~ List a → a ",
NewFnType(list{proton}, proton),
NewFnType(list{TypeVariable('a')}, TypeVariable('a')),
mSubs{'a': proton}, false},
{"List a → a → List a ~ List proton → proton → b",
NewFnType(list{TypeVariable('a')}, TypeVariable('a'), list{TypeVariable('a')}),
NewFnType(list{proton}, proton, TypeVariable('b')),
mSubs{'a': proton, 'b': list{proton}}, false},
{"(a, a, b) ~ (proton, proton, neutron)",
NewRecordType("", TypeVariable('a'), TypeVariable('a'), TypeVariable('b')),
NewRecordType("", proton, proton, neutron),
mSubs{'a': proton, 'b': neutron}, false},
}
func TestUnify(t *testing.T) {
// assert := assert.New(t)
var t0, t1 Type
var u0, u1 Type
var sub Subs
var err error
for _, uts := range unifyTests {
// logf("unifying %v", uts.name)
t0 = uts.a
t1 = uts.b
sub, err = Unify(t0, t1)
switch {
case err == nil && uts.err:
t.Errorf("Test %q - Expected an error: %v | u0: %#v, u1: %#v", uts.name, err, u0, u1)
case err != nil && !uts.err:
t.Errorf("Test %q errored: %v ", uts.name, err)
}
if uts.err {
continue
}
if uts.subs == nil {
if sub != nil {
t.Errorf("Test: %q Expected no substitution. Got %v instead", uts.name, sub)
}
continue
}
for _, s := range uts.subs.Iter() {
if T, ok := sub.Get(s.Tv); !ok {
t.Errorf("Test: %q TypeVariable %v expected in result", uts.name, s.Tv)
} else if T != s.T {
t.Errorf("Test: %q Expected TypeVariable %v to be substituted by %v. Got %v instead", uts.name, s.Tv, s.T, T)
}
}
if uts.subs.Size() != sub.Size() {
t.Errorf("Test: %q Expected subs to be the same size", uts.name)
}
sub = nil
}
}
var inferTests = []struct {
name string
expr Expression
correct Type
correctTVS TypeVarSet
err bool
}{
{"Lit", lit("1"), Float, nil, false},
{"Undefined Lit", lit("a"), nil, nil, true},
{"App", app{lit("+"), lit("1")}, NewFnType(Float, Float), nil, false},
{"Lambda", λ{"n", app{lit("+"), lit("1")}}, NewFnType(TypeVariable('a'), Float, Float), TypeVarSet{'a'}, false},
{"Lambda (+1)", λ{"a", app{lit("+1"), lit("a")}}, NewFnType(TypeVariable('a'), TypeVariable('a')), TypeVarSet{'a'}, false},
{"Var - found", variable("x"), proton, nil, false},
{"Var - notfound", variable("y"), nil, nil, true},
{"Self Infer - no err", selfInferer(true), proton, nil, false},
{"Self Infer - err", selfInferer(false), nil, nil, true},
{"nil expr", nil, nil, nil, true},
}
func TestInfer(t *testing.T) {
env := SimpleEnv{
"+": &Scheme{tvs: TypeVarSet{'a'}, t: NewFnType(TypeVariable('a'), TypeVariable('a'), TypeVariable('a'))},
"+1": &Scheme{tvs: TypeVarSet{'a'}, t: NewFnType(TypeVariable('a'), TypeVariable('a'))},
"x": NewScheme(nil, proton),
}
for _, its := range inferTests {
sch, err := Infer(env, its.expr)
if its.err {
if err == nil {
t.Errorf("Test %q : Expected error. %v", its.name, sch)
}
continue
} else {
if err != nil {
t.Errorf("Test %q Error: %v", its.name, err)
}
}
if !sch.t.Eq(its.correct) {
t.Errorf("Test %q: Expected %v. Got %v", its.name, its.correct, sch.t)
}
for _, tv := range its.correctTVS {
if !sch.tvs.Contains(tv) {
t.Errorf("Test %q: Expected %v to be in the scheme.", its.name, tv)
break
}
}
if len(its.correctTVS) != len(sch.tvs) {
t.Errorf("Test %q: Expected scheme to have %v. Got %v instead", its.name, its.correctTVS, sch.tvs)
}
}
// test without env
its := inferTests[0]
sch, err := Infer(nil, its.expr)
if err != nil {
t.Errorf("Testing a nil Env. Shouldn't have errored. Got err: %v", err)
}
if !sch.t.Eq(its.correct) {
t.Errorf("Testing nil Env. Expected %v to be in the scheme. Got scheme %v instead", its.correct, sch)
}
}
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