12 releases
0.2.7 | Mar 16, 2023 |
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0.2.6 | Jan 9, 2021 |
0.2.5 | Jul 13, 2020 |
0.2.4 | Dec 11, 2019 |
0.1.2 | Feb 24, 2019 |
#404 in Parser implementations
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Used in 27 crates
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275KB
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SLoC
lexpr: S-expressions for Rust
You may be looking for:
- API Documentation
- API Documentation for master branch
- Serde support for S-expressions
- TODO
- Goals and a survey of other S-expression crates
- Release Notes
S-expressions are the
human-readable, textual representation of code and data in the Lisp
family of languages. lexpr
aims to provide the tools to:
-
Embed S-expression data into Rust programs using the
sexp
macro:use lexpr::sexp; let address = sexp!(((name . "Jane Doe") (street . "4026 Poe Lane")));
-
Construct and destructure S-expression data using a full-featured API:
use lexpr::Value; let names = Value::list(vec!["Alice", "Bob", "Mallory"]); println!("The bad guy is {}", names[2].as_str().unwrap());
-
Parse and serialize S-expression data from and to its textual representation.
-
Use S-expressions as surface syntax for a configuration file format or other domain-specific language (DSL).
lexpr
allows obtaining source location information for the parsed data, so you can give error messages that point to the exact place a problem was detected, in case the source was parsed successfully as S-expression data, but the parsed data does not meet the requirements of your DSL.
To get a better idea of the direction lexpr
is headed, you may want
to take at the TODO or the "why"
document.
Rust version requirements
lexpr
is CI-tested on current stable, beta and nightly channels of
Rust. Additionally, it is made sure that the code still compiles on
Rust 1.45.0. However, no tests are run for that build.
Supported Lisp dialects
Currently, lexpr
focuses on Scheme, mostly based on R6RS and R7RS
syntax, with some extensions, and Emacs Lisp.
Dialect-specific omissions, both ones that are planned to be fixed in the future, and deliberate ones, are listed below. If you are missing a feature that is not yet listed here, please [file an issue]!.
Scheme
- Support for number syntax is currently quite limited, compared to Scheme's numeric tower. Integers (including hexadecimal, octal and binary notation) as well as floating point values should work though.
- For strings, continuation line syntax (using a trailing slash) is not yet implemented.
- Block comments.
- Directives, such as
#!fold-case
and#!no-fold-case
are not implemented. It's not clear if these will be implemented at all.
Emacs Lisp
- A main area where
lexpr
only supports a subset of Emacs Lisp are strings and characters. You can have a look at the gory details. - Integer literals with an arbitrary base (radix), are not yet supported.
Licensing
The code and documentation in the lexpr
crate is free
software, dual-licensed
under the MIT or Apache-2.0
license, at your choosing.
The lexpr
repository contains code and documentation adapted from
the following projects:
serde_json
, also dual-licensed under MIT/Apache-2.0 licenses.sexpr
, Copyright 2017 Zephyr Pellerin, dual-licensed under the same licenses.
Dependencies
~155KB