og

Og-Lang

v0.1.7

Index

1. Intro
2. Install
3. Basics
4. Usage
5. Build
6. Changelog
7. Todo
8. Long term utopia

Intro

To be pronounced Oh-Jee.

Oglang is an indentation based languagem mainly inspired from Livescript that compiles to a subset of GoLang but aim to be a superset and to be totally backward compatible with it. The goal is for every Go file to be a valid Og file

Bootstraped Language

Oglang is written in itself. It is said to be a 'Bootstraped' language. In fact, Oglang needs the previous release of itself to build itself.

See the Src folder for Oglang source.

And the Lib folder for the compiled one (in Golang).

Built with Antlr4 from their Golang grammar.

Goal

The main goal is to simplify the syntax, to borrow some concepts from Livescript and other functional languages, to implement Generics and macro processing, as well as some syntaxic sugar to avoid all the boilerplate code Golang forces us into.

Install

# You just have to `go get` the repo
go get -u github.com/champii/og

# If your `$PATH` includes `$GOPATH/bin` (and it should)
og --version

Basics

This is an exemple of how Oglang looks like actualy. See the Exemples folder or the Src folder.

!main // package shorthand

// No parenthesis and single word can omit quotes
import
  fmt
  strings
  "some/repo"

// Alias for `type Foo struct`
struct Foo
  // Classical property declaration
  bar int

  // Inline method declaration
  // with no arguments that returns `this.bar`
  getBar : int -> return @bar

// External Foo method declaration
Foo::inc(foo int) -> @bar = @bar + foo

// Alias for `type Bar interface`
interface Bar
  Foo()
  Bar(i int): SomeType

// Alias for struct
class Test

// Classical top-level function declaration
otherFunc(a string): string -> return a

main ->
  test := Foo{}

  test.inc(42)

  if test.getBar() == 42
    answerTheUltimateQuestion()
  else
    enterTheVoid()

  someArr := []string
    "value1"
    "value2"

  for i, v in someArray
    fmt.Println(i, v)

  switch test.getBar()
    42 => doSomething()
    _  => doDefault()

  go someFunc()

  // Auto executed closure when in goroutines
  // No need to add the extra `()`
  go -> doSomething()

Usage

NAME:
  Oglang - Golang on steroids

USAGE:
  og [options] Folders|Files

VERSION:
  v0.1.7

OPTIONS:
  -o value, --out value  Output directory. If input is recursive folder, the tree is recreated (default: "./")
  -p, --print            Print only to stdout. No files created
  -d, --dirty            Don't use 'go fmt'
  -b, --blocks           Get only the generated blocks from indent. No compilation to go.
  -v, --verbose          Show the filenames
  -h, --help             Print help
  -V, --version          Print version

Build

Here is the procedure to regenerate the parser from the grammar if you want to make changes to it.

If you just want to (re)build the binary, you can call make build or just go build (needs a previously generated parser from grammar. See below)

You will need Java, the Antlr4 library is in ./parser/antlr4-4.7.1-SNAPSHOT-complete.jar

# Get Og
go get -u github.com/champii/og
cd $GOPATH/src/github.com/champii/og

# This needs java (see above)
# As it will generate the grammar,
# Compile the existing sources,
# Regenerate the go sources from og,
# Recompile the new go sources to be sure
# And run the tests.
make

# This will just build the sources (if needed)
make build

# This needs a previously built version of `og` binary at local scope.
# Recompiles Og to Go + build + test
make bootstrap

# Needs the last official `og` binary version at global scope.
# It recompiles og from the previous global version
# Handy in case of mistake in the source or for release
make rebootstrap

# Simple exemple
og exemples/import.og

Changelog

v0.1.7: Current version

• Add custom antlr4 directly into sources. No need to build it yourself

v0.1.6

• Release system for develop

v0.1.5

• Forced Go syntax highlight on Og files for Github
• Rework translator to adapt to new method syntax and @ alias
• No need to specify the {} in interface{} for arguments types (not for return values yet)

    fn(a interface): interface{} -> a
  

v0.1.4

• Class-like method declaration (nested into the struct)

    struct Foo
      bar int
      f : int -> return @bar
  

v0.1.3

• Slice manipulation

  someArr[1:x]
  

• Interfaces

  interface Foo
    Fn(a ArgType): ResType
  

• Alias @ => this

    Foo::bar : SomeType -> return @someProp
  

v0.1.2

• Support for simple struct ID {} declaration. Still support type ID struct {}.

    // Equivalent
    struct Foo {}
    type Foo struct {}
  

• Alias class => struct.

    // Equivalent
    struct Foo {}
    class Foo {}
  

• Allow empty class declaration

    struct Foo
  

• Shorthand for package main => !main.

    // Equivalent
    !main
    package main
  

• Cli support with options and recursive directory walking

    og -o lib src
  

• External method declaration

    struct Foo
    Foo::bar -> doSomething()
  

v0.1.0

• Initial release

TODO

Golang superset goal

• const declaration
• map Type
• chan Type
• Labels
• break
• goto
• continue
• fallthrough
• select
• For with a custom variable (for i = 0; i < 10; i++)
• Method receiver pointer type
• Function literal (assignable)
• Rest params ...
• Recever type in methodExpr
• Send statement a <- b
• Binary operator (<<, >>, ., |)
• Import renaming and pattern matching
• Proper Anonymous field in structs
• Incrementation everywhere
• Make tests truly executable
• Beautyful and meaningful compile error with source context
• VSCode extension
• Adapt Golang tooling like gofmt or golint

Syntaxic Sugar Goal

• Empty statement (need to avoid skiping empty lines in preproc)
• Empty Function body
• OneLiner if/for: if a => 1, for b => b--
• Returnable and assignable statements (if, for, ...)
• Auto return for last statement in a block
• Predicat recapture: if a => that
• External type declaration like Haskell: myFunc :: string -> Foo -> Bar
• Struct compostion ("Inheritance")
• Existance test (if toto?) for non-nil value test
• Auto add default to switch ?
• pub visibility instead of capitalizing
• For with a range (for i in [0..10])
• Error bubbling
• Pattern matching
• Function currying
• Function shorthand (+ 10)
• Perfs
• Generics

Long term utopia

!main

import fmt

// Generics
struct Generic<T>
  // attributes
  pub test T

  // Instance method
  fn : T -> @test

  // Class method with external type declaration
  $ T -> Generic<T>
  pub @new(v) -> Generic<T>{ v }


// External grouped method definition
Generic<T>::(
  // With '*', tells the receiver (this or @) is a pointer to Generic<T>
  *method1 : int -> 1

  // External type declaration with no return
  $ int -> SomeComplexType -> (AnotherOne -> interface{}) -> ()
  method2(a, b, c) -> 2
)

// Returnable statements, nil existence test, predicat recapture (that)
genericFunc<T>(g Generic<T>): T -> if g.fn()? => that
                                   else       => somethingElse

// External type declaration
$ Generic<T> -> T
genericFunc<T>(g) -> g.test

// Multiple return values
$ int -> (int, string)
multipleReturn(i) -> i, "foo"

// Automatic "it" argument when not specified
$ string -> string
someFunc -> it + "Hello"

// No arguments, multiple return values, error bubbling
# (error, SomeType)
failableFunc ->
  res1 := funcsThatMayFail()?
  res2 := funcsThatFail()?

  res1 + res2

// Macro definition (like rust)
$macro my_macro ->
  ($number:expr) =>
    myFunc$(number) : int -> $number
    if $number > 0
      $my_macro($number - 1)

// Generate 10 function `myFunc10(), myFunc9(), .. myFunc0()` that all return their number,
$my_macro(10)

// Operator definition with precedence
operator ~~ 9

// Typeclass (could be implemented with macros ? lets see...)
impl SomeTypeClass for MyType
  x ~~ y = x.DoSomething(y)

main ->
  t := Generic<string>::new("str")

  // Range array creation, call chaining,
  // function currying and function shorthand.
  // Here a == [10, 11, 12, 13, 14, 15]
  a := []int{0..10}
    |> map((+ 10))
    |> filter((<= 15))

  // Function composition
  f := map >> filter