====== Using ECL (Embeddable Common-Lisp) on SDF ====== ===== What is ECL? ===== ECL stands for //Embeddable Common-Lisp// and is a free open source ANSI Common-Lisp implementation. Its distinguishing attributes are maintaining a small-footprint, and being embeddable with existing C/C++ applications. ECL is LGPL licensed and hosted at [[http://ecls.sourceforge.net/|ecls.sourceforge.net]]. ECL-11.1.1 is currently available to MetaARPA members on most SDF hosts. ===== ECL vs CLISP ===== There are currently two Common-Lisp implementations available on SDF; ECL and CLISP. Both are largely compliant with the ANSI Common-Lisp standard. Each supports various object systems, debugging, bytecode compiling, unicode, sockets, streams, etc. CLISP comes with built-in readline support; ECL doesn't, though it can be added; see the [[#asdf|ASDF]] section. In addition to being smaller and faster than CLISP, ECL can be embedded in C/C++ programs, allow embedded C/C++ code in Lisp programs, and produce stand-alone ELF executables. ECL is also very well documented. ===== ECL Basics ===== By default ECL starts up in interactive mode. Log into SDF host //miku// and type "'ecl'"; you should see something like below: ECL (Embeddable Common-Lisp) 11.1.1 Copyright (C) 1984 Taiichi Yuasa and Masami Hagiya Copyright (C) 1993 Giuseppe Attardi Copyright (C) 2000 Juan J. Garcia-Ripoll ECL is free software, and you are welcome to redistribute it under certain conditions; see file 'Copyright' for details. Type :h for Help. Top level. > The default ECL prompt is ">". Enter Common-Lisp commands in the usual way: > (+ 1 2 3) 6 > (* 4 5) 20 > (format t "hello SDF~&") hello SDF NIL > In-line help is available ; type :h for options. The debugger can be entered using "(break)" ; once entered typed :h to see options. To exit the ECL interactive session type ":exit" . ===== ECL one-liners ===== To use ECL as a script executor (ie. CGI) the //-shell// and/or //-eval// options can be used. The //-norc// is often a good addition so as to avoid unnecessary loading of modules, etc. ex: hello.lsp % echo '(format t "~&Hello SDF~&")' > hello.lsp % ecl -norc -script hello.lsp Hello SDF It's also possible to use ECL to execute simple Common-Lisp one-liners at the command line (note that //princ// is needed for screen output): % ecl -norc -shell /dev/null -eval "(princ (* 1 2 3))" 6 A nicer way to accomplish the same is to create a small shell script: #!/bin/sh # lispit - executes a lisp expression and dumps it to stdout LSP_EXPR=${@} if [ "$#" -eq 0 ]; then echo "lispit - executes a lisp expression" echo " usage: lispit '(lisp_expression)'" echo "" exit 1 fi ecl -norc -shell /dev/null -eval "(princ ${LSP_EXPR} )" echo "" exit 0 Example run: % lispit '(mapcar (lambda (x) (expt x 2)) `(1 2 3 4 5))' (1 4 9 16 25) ===== ASDF / enabling readline ===== ASDF (//Another System Definition Facility//) is an extensible build facility for Common-Lisp software. ECL comes with ASDF bundled in, however on SDF, users must setup their own ASDF repository under their $HOME directory. The following outlines the process, using the //ecl-readline// module (adds GNU readline support to ECL) as example: 1) Create the user-level ASDF repository: % mkdir -p $HOME/LISP/ASDF 2) Create the ASDF config directory and config file*: % cd $HOME % mkdir -p .config/common-lisp/source-registry.conf.d % vi .config/common-lisp/source-registry.conf.d/asdf.conf # ../asdf.conf ;;additional directory for ASDF to search (no recursion): (:directory "/LISP/ASDF/") *note: you can call the conf file anything you want. 3) Download ecl-readline module and copy select files to $HOME/LISP/ASDF: % cd /tmp % snarf http://www.common-lisp.net/project/ecl-readline/releases/ecl-readline-0.4.1.tar.gz % tar xzf ecl-readline-0.4.1.tar.gz % cd ecl-readline-0.4.1/ % cp ecl-*.* $HOME/LISP/ASDF/ 4) Create the ECL startup file: # $HOME/.eclrc (require 'asdf) (asdf:operate 'asdf:load-op 'ecl-readline) (ecl-readline::enable) The next time you startup ECL it will compile the ecl-readline module and launch an interactive session. With ecl-readline enabled the default ECL prompt is "//CL-USER[n]>//" and you should then be able to use Emacs-style command editing and history recall. If you don't like the provided prompt you can change it by editing the //ecl-readline.lisp// file. ===== Customizations ===== Additional modifications can be made to the ECL startup file, such as user-defined functions and tweaks to various modules. Below is a more nuanced example which reduces the verbosity at startup, modifies ecl-readline's history file location, and adds an external SHELL function similar to that found in CLISP: # $HOME/.eclrc (require 'asdf) (setf ASDF:*ASDF-VERBOSE* nil) ; quiets ASDF output some (setf *load-verbose* nil) ; quiets the LOAD process some (asdf:operate 'asdf:load-op 'ecl-readline) (ecl-readline::enable :history-file "/var/tmp/.ecl-history") ;; ;; customizations ;; GNU clisp-like SHELL cmd (defun shell (&optional (shell_cmd "$SHELL")) "Args: (&optional shell_cmd) SHELL calls the EXT:SYSTEM function. Executes SHELL_CMD if given, otherwise User sub-shell is spawned. SHELL_CMD be string or symbol, 256 characters max." (ext:system shell_cmd)) ===== References: ===== * //ecl(1)// and //ecl-config(1)// manpages * http://ecls.sourceforge.net/ * [[http://common-lisp.net/project/asdf/|http://common-lisp.net/project/asdf]] * [[http://common-lisp.net/project/ecl-readline/|http://common-lisp.net/project/ecl-readline]] * [[http://www.cliki.net/Getting%20Started|Getting Started with Common-Lisp]] ---- $Id: ecl_tutorial.html,v 1.4 2011/12/12 18:10:28 Exp jgw $ [[http://sdf.org/?tutorials/ecl_tutorial|Using ECL (Embeddable Common-Lisp) on SDF]] - traditional link (using [[wp>Revision_Control_System|RCS]])