dirs-rs VS rust-peg

There are several libraries that handle directory for you in the appropriate OS-specific manner.

One Rust example being https://github.com/dirs-dev/dirs-rs

> The library provides the location of these directories by leveraging the mechanisms defined by

> the XDG base directory and the XDG user directory specifications on Linux and Redox

> the Known Folder API on Windows

> the Standard Directories guidelines on macOS

Yes. We have dirs for that, folks!

I'm using dirs to get the home directory. However, dirs::home_dir() returns an Option, which I can't quite grasp how to extract the string from, and the repo doesn't have examples for it either.

And some related parser tools: - https://github.com/kevinmehall/rust-peg - https://github.com/pest-parser/pest - https://github.com/lalrpop/lalrpop

Rust is a very nice langage for implementing compilers, and has a nice ecosystem for it (logos, rust-peg, lalrpop, astmaker -- this one is mine --, etc...).

My peg crate is a parser generator that supports arbitrary token types as input. See https://github.com/kevinmehall/rust-peg/blob/master/tests/run-pass/tokens.rs for an example.

The one rust parser-generator I used is PEG

The two parser generators that I am aware of are lalrpop and PEG. There both great, and have seen some use by languages that have been written in Rust.

rust-peg

I wanted to create a parser for Apertium Stream. In 2014, I used Whittle in Ruby. If this year were 2001, I would use Lex/Yacc. Anyway, this year is 2021. I wanted to create this parser in Rust. I tried to find what is similar to Lex/Yacc. I found Rust-Peg. I found a link to Nom from Rust-Peg's document. My first impression was Nom example is easy to read. At least, its document claimed Nom is fast.

The peg crate has a resolved issue about this.

I don't really know that much about parsing and grammars, other than what I've learned about regular languages and expressions and context-free languages in a standard Theory of Comp course from my university. I basically just learned peg by reading the Wikipedia article on PEGs, reading the crate documentation to understand the syntax, and then looking at some of the peg examples on their GitHub to understand how it works in practice.