Evaluate compatibility of Medley Common Lisp (formerly XCL) with popular books about Common Lisp

[masinter]

As a Lisp learning environment, divergence from the spec in obscure edge cases may not matter as much. This might be a good goal on the way:

Evaluate and document divergence from exercises and examples for PCL and PAIP.

• paip is short for paradigms of artificial intelligence programming by peter norvig https://github.com/norvig/paip-lisp/
• pcl is practical common lisp by peter seibel https://gigamonkeys.com/book/
• http://cs.cmu.edu/~dst/lispbook/book.pdf "Gentle Introduction"
• Common Lisp: An Interactive Approach is recommended
  • The notes from an on-line course, CSE 202, using this book, and given in Fall, 2000, is available.z

This is a step toward ANSII Common Lisp compatibility which would be useful.

[reflektoin]

As a beginner using the environment it took me a while to load the CLOS in the online version. Hopefully these steps are helpful for someone in the future. So to load the CLOS I did the following steps:

1. Open Interlisp Exec. Steps for opening the Exec are explained for example here.
2. Navigate to clos folder with command "cd medley>medley>clos"
3. type "(LOAD 'DEFSYS.DFASL)" into Interlisp Exec
4. Type "(CLOS::LOAD-CLOS)" into Interlisp Exec.

Now you should be able to do class definitions using "(CLOS:DEFCLASS ...)"

[masinter]

@reflektoin I've been meaning to take this and put it in the wiki as a How To in the "Experiments" section.
Should we load CLOS by default when you ask for "Common Lisp"?
@fghalasz #742

[masinter]

@fghalasz do you think it would be useful for now to link to this issue?

[reflektoin]

@masinter: Was the question "Should we load CLOS by default when you ask for "Common Lisp"?" directed to fghalasz?

By the way, in your first post the link http://cs.cmu.edu/~dst/lispbook/book.pdf gives me "Document not found". I could access the file from link https://www.cs.cmu.edu/~dst/LispBook/book.pdf. It seems that character casing plays a role here.

[masinter]

@reflektoin you, thanks. Anyone responding to this issue.

[reflektoin]

No problem.

About loading CLOS by default. Yes I would prefer that it would be loaded by default. And that might lower the barrier for people to experiment with Common Lisp when they don't have to do extra steps on order to run CLOS code.

[pamoroso]

I'm going through Peter Seibel's book Practical Common Lisp and testing the code of each chapter on Medley to see how far I can go.

Here's my process. I evaluate the code at a XCL Exec, usually via copy-paste. If I need to load a source file I adapt and load it as explained here.

So far I completed the first three chapters. Chapter 1. Introduction: Why Lisp? has no code.

Chapter 2. Lather, Rinse, Repeat: A Tour of the REPL

Chapter 2 contains these expressions, all of which are evaluated and work as expected:

2/6> 10
10
2/7> 
(+ 2 3)
5
2/8> 

2/8> "hello, world"
"hello, world"
2/9> 
(format t "hello, world")
hello, world
NIL
2/10> 

2/10> (defun hello-world () (format t "hello, world"))
HELLO-WORLD
2/11> 

2/11> (hello-world)
hello, world
NIL
2/12> 

2/12> (defun hello-world ()
  (format t "Hello, world!"))

New FUNCTIONS definition for HELLO-WORLD.
HELLO-WORLD
2/13> 

2/13> (hello-world)
Hello, world!
NIL
2/14> 

2/14> (load "hello.lisp")

; Loading {DSK}<home>medley>il>demo>hello.lisp;1
; Finished loading {DSK}<home>medley>il>demo>hello.lisp;1, 68 bytes read
IL:|{DSK}<home>medley>il>demo>hello.lisp;1|
2/15> 

2/15> (hello-world)
Hello, world!
NIL
2/16> 

2/16> (load (compile-file "hello.lisp"))
Compiling DEFUN HELLO-WORLD ... Done

; Loading {DSK}<home>medley>il>demo>hello.DFASL;1
XCL Compiler output for source file {DSK}<home>medley>il>demo>hello.lisp;1
Source file created Friday, 8 March 2024, 7:36:06
FASL file created Friday, 8 March 2024, 7:39:58

IL:|{DSK}<home>medley>il>demo>hello.DFASL;1|

The chapter also contains an intentional call to an undefined function which enters a break loop in the example output of the book. Medley prints an error instead:

2/6> (hello-world)
Undefined car of form
HELLO-WORLD

Chapter 3. Practical: A Simple Database

I loaded the code of chapter 3 from a source file. The function make-comparisons-list calls loop with options Medley doesn't support, so I rewrote it using do like this:

(defun make-comparisons-list (fields)
  (do (result)
      ((null fields) (nreverse result))
    (push (make-comparison-expr (pop fields) (pop fields)) result)))

With this change the code works as expected and lets me call select and where, which in Seibel's code rely on the loop version of make-comparisons-list:

NIL
2/6> (load "packages.lisp" :package (find-package "XCL-USER"))

; Loading {DSK}<home>medley>il>demo>packages.lisp;4
; Finished loading {DSK}<home>medley>il>demo>packages.lisp;4, 95 bytes read
IL:|{DSK}<home>medley>il>demo>packages.lisp;4|
2/7> (load "simple-database.lisp" :package (find-package "XCL-USER"))

; Loading {DSK}<home>medley>il>demo>simple-database.lisp;4
; Finished loading {DSK}<home>medley>il>demo>simple-database.lisp;4, 2150 bytes read
IL:|{DSK}<home>medley>il>demo>simple-database.lisp;4|
2/8> (setf *package* (find-package "COM.GIGAMONKEYS.SIMPLE-DB"))
#<Package COM.GIGAMONKEYS.SIMPLE-DB>
2/9> (add-cds)
Title: The Little Interlisper
Artist: W.R. Iter
Rating: 9
Ripped [y/n]: y
Another? [y/n]: n
NIL
2/10> (select (where :title "The Little Interlisper"))
((:TITLE "The Little Interlisper" :ARTIST "W.R. Iter" :RATING 9 :RIPPED T))
2/11> (select (where :rating 9))
((:TITLE "The Little Interlisper" :ARTIST "W.R. Iter" :RATING 9 :RIPPED T))
2/12> (dribble)

[pamoroso]

Concerning the earlier comments on CLOS, I believe it comes preloaded with recent builds and it's no longer necessary to load it manually.