atproto_mlf

Alpha, pre-release. Pre-1.0 and evolving; expect breaking changes between 0.x releases. Upstream mlf is itself pre-release.

Parse and print mlf (“Matt’s Lexicon Format”) against the atproto_lexicon AST, with a bidirectional CLI for converting whole lexicon file trees. A clean-room Gleam implementation of the upstream grammar, oracle-tested against upstream’s own snapshot fixtures.

Installation

gleam add atproto_mlf

Usage

Library:

import atproto_mlf

let assert Ok(doc) = atproto_mlf.parse(source, "com.example.thread")
// doc is an atproto_lexicon ast.LexiconDoc; encode it, diff it, feed codegen.

CLI (walks both .mlf and .json inputs; four directions from one model: compile, convert, normalize, fmt):

gleam run -m atproto_mlf -- <src-dir> <out-dir> [--to json|mlf]

NSIDs derive from file paths (com/example/thread.mlf becomes com.example.thread). Constructs the lexicon spec allows but mlf cannot express (e.g. a procedure with both query parameters and a non-JSON input body) produce a spanned error naming the construct; nothing is ever silently dropped.

Architecture

Source -> lexer -> parser -> lower -> atproto_lexicon AST -> printer -> mlf text; the CLI drives both directions over a file tree.

Modules

Module	What it does
`atproto_mlf`	Public API: `parse` turns mlf source into an `atproto_lexicon` `LexiconDoc`; `main` runs the CLI.
`atproto_mlf/error`	`ParseError` + `describe`, returned by `parse`.
`atproto_mlf/printer`	`PrintError` + `describe` + `print`: AST back to mlf text, total or a named `PrintError`.

cli, lexer, lower, mlf_ast, parser, pipeline, and token are internal.