weberc2/tdl

README

Disclaimer: This is an experiment in code generation; it's largely a project for my own amusement and utility. Don't use this in production.

tdl is a terse, expressive type description language. For now, I'm using it to generate Go boilerplate, which is particularly useful for modeling sum types. Besides generating type declarations, tdl could also be used to generate serializers/deserializers/validators, and not just for Go but for any language. This would make it usable as a simplified, expressive alternative for protobufs. I'd really like to use it as the type grammar of a ML-like language that compiles to Go.

If any of this interests you, drop me a line: [email protected]

TDL-GO

Right now, there is only one implementation (tdl-go)--a Go type definition compiler (tdl goes in, Go type stubs come out). Eventually I want to build the aforementioned applications as well as compilers for other languages (tdl-py and tdl-js are high on my list).

INSTALL

The repository contains generated.go, which is generated from types.tdl, so all you need to install the compiler is the go toolchain: go install ./tdl-go.

USAGE

tdl-go currently reads from stdin and writes to stdout, so you invoke it like this: cat ./types.tdl | tdl-go > ./generated.go.

EXAMPLES

tdl-go is self-hosted, so check out its type description and the generated output. Also, ./examples/json contains a toy program that serializes Go data types to JSON by first converting them to generated JSON types.

Here is the type description for TDL's AST:

type Ident = string

type Field = {Name Ident; Type Type}

type Enum = []Field

type Struct = []Field

type Tuple = []Type

type Pointer = {Type Type}

type Slice = {Type Type}

type Type = Ident Ident
    | Enum Enum
    | Struct Struct
    | Tuple Tuple
    | Pointer Pointer
    | Slice Slice

type TypeDecl = {Name Ident; Type Type}