dolt/nomdl/codegen

To update the codegen there are some subtleties because the code depends on generated code.

Build a working version

First step is to build a binary.

cd nomdl/codegen/
go build

Change templates

Not much to say here but you can see the result without breaking things

./codegen --in=test/struct.noms

This generates test.noms.go in the current directory. Iterate until it looks correct.

Change system go files

There are a few files that are generated that codegen itself depends on.

1. types/compound_blob_struct.noms.go
2. datas/types.noms.go

Both of these can be updated by running go generate in their respective directories

There is also one more file that is generated but it requires manual intervention

types/package_set_of_ref.go

This one is generated from types/package_set_of_ref.noms. However, it uses the symbol Package to refer to a types.Package. Currently we have no convenient way to make this work out of the box. However, it is pretty straight forward to make it work.

1. Open nomdl/pkg/grammar.pg
2. Find UInt64
3. At that line, add one more builtin type called Package.
4. Run go generate in nomdl/pkg
5. Run go run ../nomdl/codegen/codegen.go --in=package_set_of_ref.noms in types/.

Here is the diff:

--- a/nomdl/pkg/grammar.peg
+++ b/nomdl/pkg/grammar.peg
@@ -159,7 +159,7 @@ CompoundType <- `List` _ `(` _ t:Type _ `)` _ {
        return types.MakeCompoundType(types.RefKind, t.(types.Type)), nil
 }

-PrimitiveType <- p:(`UInt64` / `UInt32` / `UInt16` / `UInt8` / `Int64` / `Int32` / `Int16` / `Int8` / `Float64` / `Float32` / `Bool` / `String` / `Blob` / `Value` / `Type`) {
+PrimitiveType <- p:(`UInt64` / `UInt32` / `UInt16` / `UInt8` / `Int64` / `Int32` / `Int16` / `Int8` / `Float64` / `Float32` / `Bool` / `String` / `Blob` / `Value` / `Type` / `Package`) {
        return types.MakePrimitiveTypeByString(string(p.([]uint8))), nil
 }

Once #577 is fixed this will need no manual intervention.