Alias a few more things back into the root package.

Many of these will be transitional only, I think,
but we'll see what the appropriate timescale is for that.
It may be fine to leave them for quite a while.

With these aliases, I've been able to substitute this branch in
to... approximately all of our downstreams I know about,
and all their tests still pass.  That includes packages that
have codegen outputs committed already (!).  That includes go-ipfs,
and thus includes all of the transitives between us and it.

I think that means we're truly able to claim this will be a
"no breaking changes" scenario when we merge this and
it next comes time to tag a release.

(Golang's alias feature is kind of incredible.  I'm really happy.)

datamodel.go

@@ -2,6 +2,7 @@ package ipld
 
 import (
 	"github.com/ipld/go-ipld-prime/datamodel"
+	"github.com/ipld/go-ipld-prime/schema"
 )
 
 type (
@@ -21,3 +22,91 @@ type (
 	Path        = datamodel.Path
 	PathSegment = datamodel.PathSegment
 )
+
+var (
+	Null   = datamodel.Null
+	Absent = datamodel.Absent
+)
+
+const (
+	Kind_Invalid = datamodel.Kind_Invalid
+	Kind_Map     = datamodel.Kind_Map
+	Kind_List    = datamodel.Kind_List
+	Kind_Null    = datamodel.Kind_Null
+	Kind_Bool    = datamodel.Kind_Bool
+	Kind_Int     = datamodel.Kind_Int
+	Kind_Float   = datamodel.Kind_Float
+	Kind_String  = datamodel.Kind_String
+	Kind_Bytes   = datamodel.Kind_Bytes
+	Kind_Link    = datamodel.Kind_Link
+)
+
+// Future: These aliases for the `KindSet_*` values may be dropped someday.
+// I don't think they're very important to have cluttering up namespace here.
+// They're included for a brief transitional period, largely for the sake of codegen things which have referred to them, but may disappear in the future.
+var (
+	KindSet_Recursive  = datamodel.KindSet_Recursive
+	KindSet_Scalar     = datamodel.KindSet_Scalar
+	KindSet_JustMap    = datamodel.KindSet_JustMap
+	KindSet_JustList   = datamodel.KindSet_JustList
+	KindSet_JustNull   = datamodel.KindSet_JustNull
+	KindSet_JustBool   = datamodel.KindSet_JustBool
+	KindSet_JustInt    = datamodel.KindSet_JustInt
+	KindSet_JustFloat  = datamodel.KindSet_JustFloat
+	KindSet_JustString = datamodel.KindSet_JustString
+	KindSet_JustBytes  = datamodel.KindSet_JustBytes
+	KindSet_JustLink   = datamodel.KindSet_JustLink
+)
+
+// Future: These error type aliases may be dropped someday.
+// Being able to see them as having more than one package name is not helpful to clarity.
+// They are left here for now for a brief transitional period, because it was relatively easy to do so.
+type (
+	ErrWrongKind             = datamodel.ErrWrongKind
+	ErrNotExists             = datamodel.ErrNotExists
+	ErrRepeatedMapKey        = datamodel.ErrRepeatedMapKey
+	ErrInvalidSegmentForList = datamodel.ErrInvalidSegmentForList
+	ErrIteratorOverread      = datamodel.ErrIteratorOverread
+	ErrInvalidKey            = schema.ErrInvalidKey
+	ErrMissingRequiredField  = schema.ErrMissingRequiredField
+)
+
+// Future: a bunch of these alias methods for path creation may be dropped someday.
+// They don't hurt anything, but I don't think they add much clarity either, vs the amount of namespace noise they create;
+// many of the high level convenience functions we add here in the root package will probably refer to datamodel.Path, and that should be sufficient to create clarity for new users for where to look for more on pathing.
+// They are here for now for a transitional period, but may eventually be revisited and perhaps removed.
+
+// NewPath is an alias for datamodel.NewPath.
+//
+// Pathing is a concept defined in the data model layer of IPLD.
+func NewPath(segments []PathSegment) Path {
+	return datamodel.NewPath(segments)
+}
+
+// ParsePath is an alias for datamodel.ParsePath.
+//
+// Pathing is a concept defined in the data model layer of IPLD.
+func ParsePath(pth string) Path {
+	return datamodel.ParsePath(pth)
+}
+
+// ParsePathSegment is an alias for datamodel.ParsePathSegment.
+//
+// Pathing is a concept defined in the data model layer of IPLD.
+func ParsePathSegment(s string) PathSegment {
+	return datamodel.ParsePathSegment(s)
+}
+
+// PathSegmentOfString is an alias for datamodel.PathSegmentOfString.
+//
+// Pathing is a concept defined in the data model layer of IPLD.
+func PathSegmentOfString(s string) PathSegment {
+	return datamodel.PathSegmentOfString(s)
+}
+
+// PathSegmentOfInt is an alias for datamodel.PathSegmentOfInt.
+//
+// Pathing is a concept defined in the data model layer of IPLD.
+func PathSegmentOfInt(i int64) PathSegment {
+	return datamodel.PathSegmentOfInt(i)
+}

linking.go

@@ -8,3 +8,10 @@ type (
 	LinkSystem  = linking.LinkSystem
 	LinkContext = linking.LinkContext
 )
+
+type (
+	BlockReadOpener     = linking.BlockReadOpener
+	BlockWriteOpener    = linking.BlockWriteOpener
+	BlockWriteCommitter = linking.BlockWriteCommitter
+	NodeReifier         = linking.NodeReifier
+)