EusLisp tutorial

About

EusLisp is a Lisp dialect designed for robot programming.

This tutorial is aimed to ones that already have some experience with other programming languages, but are completely new to EusLisp.

Ones that want to learn more about the inner processes or to have more detailed explanations should refer to the original documentation.

For more information on robotic engineering, please refer to an appropriate textbook.

EusLisp main features

  • Is a language specialized in robot programming.
  • Solid 3D modeling library.
  • Is applicable to any robot supported by ROS and/or OpenHRP.

Install

To install ROS, please follow instructions on the following link: ROS/Installation. It is recommended to also install wstool and catkin-tools.

sudo apt-get install python-wstool python-catkin-tools

When finished with installation, create a catkin workspace like in the following.

mkdir ~/catkin_ws
cd ~/catkin_ws
wstool init src
catkin init
catkin build
source ~/catkin_ws/devel/setup.bash

Manual installation from ROS

Packages like ros-<ROS_DISTRO>-roseus are provided. For instance, in indigo EusLisp can be installed as follows.

sudo apt-get install ros-indigo-roseus

In order to run the robot model used by this tutorial, the install of rtmros_common is also necessary.

sudo apt-get install ros-indigo-hrpsys-ros-bridge ros-indigo-euscollada ros-indigo-pr2eus

Finally, download rtmros_tutorials into the previously created catkin workspace.

cd <catkin_ws>/src
wstool set rtm-ros-robotics/rtmros_tutorials https://github.com/start-jsk/rtmros_tutorials.git --git
wstool update rtm-ros-robotics/rtmros_tutorials
cd rtm-ros-robotics/rtmros_tutorials/hrpsys_ros_bridge_tutorials
catkin bt

Installer for ROS, HRPSYS and EusLisp

jsk_common makes possible to install a variety of tools for robot programming, including ROS, hrpsys and EusLisp.

Basic Usage

Launching the Interpreter

EusLisp is mainly used from the interpreter. With ROS installed, the common is to use "roseus".

  • Minimal usage
eusgl
  • Launch with irteus expansion + GUI
irteusgl
  • Launch with irteusgl + ROS interface
roseus

Since the EusLisp interpreter does not support readline, it is not able to:

  • Navigate through the history
  • Use cursor keys

In order to avoid this problem, it is recommended to use emacs shell. After starting emacs, doing M-x shell will launch the shell. In emacs shell, the history can be navigated with M-p, the cursor keys can be used, results can be accumulated in the buffer, besides many other benefits.

Using the Interpreter

In EusLisp interpreter, there is no difference between capital and lowercase letters, and the outer parenthesis () can be omitted.

For example:

(+ 1 2)

Is equal to:

+ 1 2

However, it is necessary to use inner parenthesis.

+ (- 3 2) 1

Variables can be set with setq.

(setq a (+ 1 2))

* can be used to access the previous result.

For example, in the following * is substituted with the previous result, that is, 3.

(+ 1 2)
(setq a *)

** and *** work similarly, accessing the 2nd last result and 3rd last result.

Session can be finished with exit or Ctrl+D.

(exit)

Writing programs

EusLisp programs conventionally use the extension .l. Loading one of these files in the interpreter is equivalent to typing all of its contents. No compile is performed when loading, and there is no entry point (main functions).

A file test.l can be loaded by starting the interpreter with the file name as argument

roseus test.l

or by calling the load function from the interpreter.

(load "test.l")