Interpres

Interpres is a LISP that allows programmers to create their own language DSL, targeted at any platform. A programmer may for example decide to implemented an if and whilefunction, that compile to the JVM.

To make this possible, Interpres programs output a sequence of assembly instructions. Consider the following example for an imaginary assembly language:

; The language DSL. Defines + and print-int
(interpres/define @print-int (interpres/lambda (int)
  (interpres/list int (asm/call @"PUTINT") (asm/call @"PUTEOL"))))

(interpres/define @+ (interpres/lambda (first-integer second-integer)
  (interpres/list (asm/loadl first-integer) (asm/loadl second-integer) (asm/call @"ADD"))))

(interpres/define @asm/loadl (interpres/lambda (literal)
  (interpres/string/conat @"LOADL " literal)))

(interpres/define @asm/call (interpres/lambda (address)
  (interpres/string/concat @"CALL " address)))

Which can be used in the following way:

; An actual program, using the above definitions
(print-int (+ 1 2)) ; => ["LOADL 1", "LOADL 2", "CALL ADD", "CALL PUTINT", "CALL PUTEOL"]

Please head over to interpres-imperative to get a more specific idea of what is possible.

Features

• Adding definitions using define
• Lexical scope with bind
• Lambda functions with default arguments
• Let-in expressions
• Backtrace with line numbers and filename
• Quoting and unquoting (code as data)
• Builtin functions to work with lists, symbols, strings, characters and integers
• Requiring of files relative to current file

Usage instructions

Download the latest release from thomasbrus/interpres/releases. Place the JAR in your classpath and execute the following command:

java interpres.App my-dsl.interpres

See examples/language for a few examples. See thomasbrus/interpres-imperative/examples for some more interesting examples.

Development

Prerequisites

This project requires the following software to be installed:

• Maven
• JDK 1.8

To make sure that Maven uses the correct JDK version, alter the JAVA_HOME environment variable, or place this in your ~/.mavenrc:

export JAVA_HOME=/Library/Java/JavaVirtualMachines/<jdk-version-1.8>/Contents/Home

Use mvn --version to verify that everything is setup correctly.

Compilation

Using Maven, the project is compiled by issuing the mvn compile command. The project can then be run by providing a programming written in Interpres and passing it to the main app:

$ mvn compile
$ mvn exec:java -Dexec.mainClass="interpres.App" my-program.interpres

An alternative way is using mvn package. This will not produce as much debugging output and it does not hang for a few seconds each time.

$ mvn package
$ java -classpath target/interpres-<version>.jar interpres.App my-program.interpres

Motivation

This project was part of the Compiler Design course at the Unversity of Twente. Download final report (Dutch)

License

See LICENSE.txt.