263caee564
* fix: don't shadow local bindings with dynamics
This commit adds a new lookup preference to the evaluator, LookupLocal,
and uses it to lookup bindings in the scope of let forms. This fixes an
issue whereby our original bias toward dynamic bindings would prevent
users from shadowing dynamic bindings with local bindings of the same
name. Before the following code returned `command c`:
```
(defdynamic test-val (let [c (car (list 1 2 3))]
c))
```
It now returns `1`.
I also fixed a small issue with top-level (as in, without a
corresponding function environment) let forms (they'd cause a crash for
lack of an environment parent).
Fixes #659
* refactor: only prefer local lookups for shadows
The prior commit introduced a local lookup preference into the evaluator
in order allow for shadowing of global names in local scopes (like let
bindings). However, this introduced prohibitive performance costs,
especially for dynamic functions.
To mitigate this, we only perform local-biased lookups for a set of
known-shadows. Since we know the names of local bindings at form
evaluation time, we can restrict our local lookup bias to these paths
only. This greatly reduces the performance penalties initially incurred
by the change.
I've also refactored some of the lookup code for clarity.
* fix: support recursive let bindings
Previously, the bodies of anonymous functions bound to a let name did
not have access to their names, making recursion such as:
```
(let [f (fn [x] (if (= x 1) x (f (dec x))))] (f 10))
```
impossible. We now equip evaluation of let bindings with an additional
recursion environment making this possible. The example above will now
resolve to `1`.
Fixes #1133
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| app | ||
| bench | ||
| core | ||
| docs | ||
| examples | ||
| headerparse | ||
| resources | ||
| scripts | ||
| src | ||
| test | ||
| .build.yml | ||
| .clang-format | ||
| .dir-locals.el | ||
| .gitignore | ||
| .travis.yml | ||
| CarpHask.cabal | ||
| default.nix | ||
| LICENSE | ||
| LUA_LICENSE | ||
| README.md | ||
| Setup.hs | ||
| stack.yaml | ||
Carp
WARNING! This is a research project and a lot of information here might become outdated and misleading without any explanation. Don't use it for anything important just yet!
Version 0.5 of the language is out!
About
Carp is a programming language designed to work well for interactive and performance sensitive use cases like games, sound synthesis and visualizations.
The key features of Carp are the following:
- Automatic and deterministic memory management (no garbage collector or VM)
- Inferred static types for great speed and reliability
- Ownership tracking enables a functional programming style while still using mutation of cache-friendly data structures under the hood
- No hidden performance penalties – allocation and copying are explicit
- Straightforward integration with existing C code
- Lisp macros, compile time scripting and a helpful REPL
Learn more
- The Compiler Manual - how to install and use the compiler
- Carp Language Guide - syntax and semantics of the language
- Core Docs - documentation for our standard library
A Very Small Example
(load-and-use SDL)
(defn tick [state]
(+ state 10))
(defn draw [app rend state]
(bg rend &(rgb (/ @state 2) (/ @state 3) (/ @state 4))))
(defn main []
(let [app (SDLApp.create "The Minimalistic Color Generator" 400 300)
state 0]
(SDLApp.run-with-callbacks &app SDLApp.quit-on-esc tick draw state)))
For instructions on how to run Carp code, see this document.
For more examples, check out the examples directory.
Maintainers
Contributing
Thanks to all the awesome people who have contributed to Carp over the years!
We are always looking for more help – check out the contributing guide to get started.
License
Copyright 2016 - 2020 Erik Svedäng
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
The regular expression implementation as found in src/carp_regex.h are Copyright (C) 1994-2017 Lua.org, PUC-Rio under the terms of the MIT license. Details can be found in the License file LUA_LICENSE.