YamlMod

Overview

YamlMod is an emacs-module to parse yaml, written in Rust.

Usage

YamlMod provides functions for parsing yaml string (yamlmod-load) and yaml file (yamlmod-read-file). Additionally, it provides a function yamlmod-ypath-search to get character index to navigate in a yaml string. The output from yamlmod-ypath-search can be used to jump in a yaml file with goto-char

Elisp Examples

(yamlmod-load "yes")                                                  ;; => 't
(yamlmod-load "no")                                                   ;; => nil
(yamlmod-load "[1, 2, 3]")                                            ;; => [1 2 3] ;; a vector object
(yamlmod-load "{a: 1, b: 2}")                                         ;; => #<hash-table equal 2/65 0x4e436fe1>

(setq test (yamlmod-load "{a: 1, b: 2}"))
(gethash "b" test)                                                    ;; => 2 (#o2, #x2, ?\C-b)


;; Parse a yaml file to elisp data structure
(setq file-yaml (yamlmod-read-file "/path/to/filename.yml"))

;; Get character index in a yaml string using ypath (a nested 
;; key lookup separated by period). The index starts with 1 for 
;; use with `goto-char`
(yamlmod-ypath-search "{a: [1, 2], b: {c: [3, 4]}}" "a")              ;; => 2
(yamlmod-ypath-search "{a: [1, 2], b: {c: [3, 4]}}" "a.2")            ;; => 9
(yamlmod-ypath-search "{a: [1, 2], b: {c: [3, 4]}}" "a.b")            ;; => 13
(yamlmod-ypath-search "{a: [1, 2], b: {c: [3, 4]}}" "a.b.2")          ;; => nil ;; for not found

Installation

Build instruction

git clone https://github.com/perfectayush/emacs-yamlmod.git
cd emacs-yamlmod
make

Build requires rust and cargo to be pre-installed.

Load in Emacs

(add-to-load-path "/path/to/directory/for/emacs-yamlmod")
(require 'yamlmod-wrapper)

This module depends on f.el. It should be present on load path

Motivation

This is an attempt to hack Emacs, along with learning some Rust. It's a simple project with quickly perceivable results.

Another yaml parsing dynamic emacs module is available at emacs-libyaml. I have hacked up on emacs-libyaml in past, but it felt very low-level to code in C. Rust seemed a good fit to achieve same feature set in a much simpler codebase.

Thanks to emacs-module-rs and yaml-rust for making this implementation a lot easier.

Known Issues

• Currently, all boolean like strings "yes", "Yes", "no", "No", "True", "False" etc. are always parsed as 't or nil, even if they are quoted.
• Only tested on macOS, but should be portable on other platforms.

Todos

• Write a dump function to dump elisp data structure to yaml