vam: type value comparisons

[mattnibs]

No description provided.

[nwt]

This should match what happens on the other side of the fence.

super/runtime/sam/expr/sort.go

Lines 205 to 211 in 3d706f2

	case aid == super.IDType:
	zctx := super.NewContext() // XXX This is expensive.
	// XXX This isn't cheap eventually we should add
	// super.CompareTypeValues(a, b zcode.Bytes).
	av, _ := zctx.DecodeTypeValue(a.Bytes())
	bv, _ := zctx.DecodeTypeValue(b.Bytes())
	return super.CompareTypes(av, bv)

.

And since performance on type comparisons doesn't matter much, I don't think it's worth generating code and suggest we just handle it with a loop over in compare.go.

[mattnibs]

ok

[mattnibs]

You are referencing sort, for equality comparisons on type values we just compare bytes:

super/runtime/sam/expr/coerce/coerce.go

Lines 18 to 20 in 98f94ff

	switch aid, bid := a.Type().ID(), b.Type().ID(); {
	case !super.IsNumber(aid) || !super.IsNumber(bid):
	return aid == bid && bytes.Equal(a.Bytes(), b.Bytes())

[nwt]

Oh, boy. We do different things depending on whether the right-hand side of the comparison is constant.

$ echo '{i32:<int32>,i64:<int64>}' | super -c 'yield i32 < i64, i32 < <int64>' -
op <
false
true

We should fix that but obviously not here.

[mattnibs]

@mccanne has proposed dropping the comparison constant optimization for sam which I'm beginning to agree with.