ncjdjyh / jcscheme

Another Scheme dialect written in Java

JCScheme

The very first toy language I wrote for studying the essence of programing language.

JCScheme = Jiacai's Scheme 😊

Concepts

1. S-expression

JCScheme use S-expression internally to represent AST like any other Scheme.

FYI, diagram below is the S-expression of (+ 1 2 (* 3 4)) behind SExpression.java.

2. eval-apply cycle

As for evaluating code, JCScheme models after eval-apply cycle described in SICP 4.1

More explanations can be found in my Chinese blog 《我的第一个玩具语言 JCScheme 问世了》。

Install

git clone [email protected]:jiacai2050/JCScheme.git
cd JCScheme; mvn clean package
java -jar target/JCScheme-*.jar

You can install rlwrap to support line editing, persistent history and completion.

# ubuntu
sudo apt-get install rlwrap
# centos
sudo yum install rlwrap
# Mac
brew install rlwrap  # for Homebrew
port install rlwrap  # for MacPorts

Then, run JCScheme like this

rlwrap java -jar target/JCScheme-*.jar

Syntax

1. datatype
   • number
   • bool
   • string
   • pair
   • list
   • function
2. builtin keywords
   • if
   • def
   • lambda
3. builtin functions
   • bool: and、 or、 not
   • number: +、 -、 *、 /、 >、 <、 =
   • pair/list: cons、 car、 cdr、 list、 null?
   • string: str=?、
   • other: print

Code snippets can be found in ChangeLog

TODO

• function application using normal order. Done at 2016-03-05, details can be found at this branch

License

MIT License © Jiacai Liu