Generate AST types from ASDL (Abstract Syntax Description Language) descriptions.

asdl

parser

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Author

tonyyuyiding

Version

0.1.0

License

MIT

Repository

github.com/tonyyuyiding/asdl.mbt

Last updated

12 hours ago

Downloads

Dependencies

moonbitlang/parser0.3.19
moonbitlang/x0.5.5

#tonyyuyiding/asdl

Generate AST types from ASDL (Abstract Syntax Description Language) descriptions.

This project is under development. We will try to keep the API stable, but breaking changes might still occur in some cases.

#Usage

#CLI

moon run cmd/asdl-gen path/to/schema.asdl --target moonbit -o schema.mbt

Omit -o to print to stdout. Use --target to specify target language (default: moonbit).

Only the MoonBit backend is available currently. Additional language emitters have been planned.

#Library

///|
test "asdl_to_moonbit" {
  let asdl =
    #|module Expr {
    #|    expr = Num(int n) | Add(expr left, expr right)
    #|}
  let code = @asdl.asdl_to_moonbit(asdl)
  let expected =
    #|///|
    #|pub type Identifier = StringView
    #|
    #|///|
    #|pub(all) enum Expr {
    #|  Num(n~ : Int)
    #|  Add(left~ : Expr, right~ : Expr)
    #|} derive(Debug)
    #|
    #|///|
    #|pub extend Expr with Debug::{ to_repr }
    #|
  assert_eq(code, expected)
}

#Pipeline

Stage	Package	Role
Lexer	lexer/	Tokenize ASDL source
Parser	parser/	Build an ASDL module AST
Checker	checker/	Validate type names and definitions
Backend	backend/	Emit target-language source (MoonBit today)

The root package re-exports these stages and provides asdl_to_moonbit as a single entry point: tokenize → parse → check → emit.

#Bootstrapping

ASDL can describe itself. parser/asdl.asdl is a meta-schema for ASDL modules, definitions, constructors, and fields:

module ASDL {
    module = (identifier name, definition* definitions)

    definition = Product(identifier name, field* fields)
               | Sum(identifier name, constructor* constructors, field* attributes)

    constructor = (identifier name, field* fields)

    field = (identifier type, quantifier? quant, identifier? name)

    quantifier = Optional | Sequence
}

Feeding this file through the generator produces parser/ast.mbt — the MoonBit types being used by the parser :D

CheckError

source

using @tonyyuyiding/asdl/checker { type CheckError }

Offset

source

type Offset = Int

ParseError

source

using @tonyyuyiding/asdl/parser { type ParseError }

Token

source

using @tonyyuyiding/asdl/lexer { type Token }

TokenBody

source

using @tonyyuyiding/asdl/lexer { type TokenBody }

TokenizeError

source

using @tonyyuyiding/asdl/lexer { type TokenizeError }

asdl_to_moonbit

source

fn asdl_to_moonbit(code : StringView) -> String raise

check_types

source

fn check_types(module_ : @tonyyuyiding/asdl/parser.Module
Module) -> Unit raise @tonyyuyiding/asdl/checker.CheckError
CheckError

emit_moonbit

source

fn emit_moonbit(module_ : @tonyyuyiding/asdl/parser.Module
Module) -> String

parse_tokens

source

fn parse_tokens(tokens : Array[@tonyyuyiding/asdl/lexer.Token
Token]) -> @tonyyuyiding/asdl/parser.Module
Module raise @tonyyuyiding/asdl/parser.ParseError
ParseError

tokenize

source

fn tokenize(code : StringView) -> Array[@tonyyuyiding/asdl/lexer.Token
Token] raise @tonyyuyiding/asdl/lexer.TokenizeError
TokenizeError

Source Files

asdl.mbt

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asdl

#tonyyuyiding/asdl

#Usage

#CLI

#Library

#Pipeline

#Bootstrapping

#CheckError

#Offset

#ParseError

#Token

#TokenBody

#TokenizeError

#asdl_to_moonbit

#check_types

#emit_moonbit

#parse_tokens

#tokenize

Source Files

CheckError

Offset

ParseError

Token

TokenBody

TokenizeError

asdl_to_moonbit

check_types

emit_moonbit

parse_tokens

tokenize