Message in macro printed twice - macros

I wrote a function which can accept any kind, any number of arguments and so that it can print the name and value of the arguments. The function works as expected. But I don't like the function call requires me to pass a quote of value like this (my-message 'emacs-version 'emacs-copyright). I want to simplified to (my-message emacs-version emacs-copyright). Therefore I use macro to rewrite the function.
(defmacro my-message (&rest args)
(if args
(progn
(message "This is the start of debug message.\n")
(dolist (arg args)
(cond
((stringp arg)
(message arg))
((numberp arg)
(message (number-to-string arg)))
((boundp arg)
(pp arg)
(message "")
(pp (symbol-value arg)))
((not (boundp arg))
(pp arg)
(message "Undefined")))
(message "\n"))
(message "This is the end of debug message."))
(message "This is a debug message ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~")))
However, the some of the message are printed twice.
(my-message emacs-version emacs-copyright 12345 "HelloWorld" foobar)
This is the start of debug message.
emacs-version
"24.5.1"
[2 times]
emacs-copyright
"Copyright (C) 2015 Free Software Foundation, Inc."
[2 times]
12345
[2 times]
HelloWorld
[2 times]
foobar
Undefined
[2 times]
This is the end of debug message.
What is the problem?

You are using macros for a wrong reason.
A macro is not just a gimmick to avoid an extra character in your code.
Macros operate on code.
IOW, the code you wrote is executed at compile time (or macroexpansion time, if not compiled) and the result is then used instead of the macro form.
So, the symbol (and, more generally, sexp) section of your macro should look like
`(message "symbol: %s, value: %s" ',arg ,arg)
Read up on backquote if you don't understand the above.
However, let me repeat: macros are "advanced material" and you might prefer to avoid them until you are more comfortable with Lisp.

I think the message
[2 times]
in your output refers to an extra newline character.
This behavior can be reproduced by evaluating
(progn
(message "HelloWorld")
(message "\n"))
in *scratch*. The output in *messages* is
HelloWorld
[2 times]
"
"
I wonder if this behavior is intended.
Maybe I did misunderstand your question since my answer has nothing to do with macros.

Related

How to evaluate Common Lisp code in non-slime buffers?

I'd like to be able to get my SBCL 1.4.5 (Linux x86_64)
Emacs 'inferior-lisp-process' to evaluate a S-Expression (sexp)
in some Emacs buffer that is not the 'slime' buffer - I have
latest quicklisp and slime-2.20 .
I thought this was exactly the same issue as in :
How to run Common Lisp code with Slime in Emacs Lisp
but it is not - my issue is that when I try to run 'slime-eval' or
any slime 'run in inferior-lisp-process' method ALL symbols seem to be
being looked up in ONLY in the SWANK-IO-PACKAGE namespace :
In my Emacs '*scratch*' buffer:
(slime-eval '(symbolp '+) "CL-USER")
Produces a backtrace error:
The function SWANK-IO-PACKAGE::SYMBOLP is undefined.
[Condition of type UNDEFINED-FUNCTION]
Restarts:
0: [CONTINUE] Retry calling SWANK-IO-PACKAGE::SYMBOLP.
1: [USE-VALUE] Call specified function.
2: [RETURN-VALUE] Return specified values.
3: [RETURN-NOTHING] Return zero values.
4: [*ABORT] Return to SLIME's top level.
5: [ABORT] abort thread (#<THREAD "worker" RUNNING {100262C8E3}>)
Backtrace:
0: ("undefined function" SWANK-IO-PACKAGE::+)
1: (SB-INT:SIMPLE-EVAL-IN-LEXENV \
(SWANK-IO-PACKAGE::SYMBOLP (QUOTE SWANK-IO-PACKAGE::+)) \
#<NULL-LEXENV>)
2: (EVAL (SWANK-IO-PACKAGE::SYMBOLP (QUOTE SWANK-IO-PACKAGE::+)))
It makes no difference whether I do :
(slime-eval '(symbolp :+) "CL-USER")
OR
(slime-eval '(symbolp '+))
I still get the same error because '+ and :+ are
always looked up only in the SWANK-IO-PACKAGE namespace.
I found this by simply trying to run, for my first test:
(slime-eval '(+ 2 2) "CL-USER")
which prints in the output buffer another backtrace
The function SWANK-IO-PACKAGE::+ is undefined.
[Condition of type UNDEFINED-FUNCTION]
I did try the code snippet from Question #22456086 :
(require 'slime)
(defun slrepl (str)
"Eval STR as Common Lisp code."
(unless (slime-current-connection)
(let ((wnd (current-window-configuration)))
(slime)
(while (not (and (slime-current-connection)
(get-buffer-window (slime-output-buffer))))
(sit-for 0.2))
(set-window-configuration wnd)))
(let (deactivate-mark)
(cadr (slime-eval `(swank:eval-and-grab-output ,str)))))
So doing:
(slrepl '(symbol-function '+))^X^E
Still results in :
The function SWANK-IO-PACKAGE::SYMBOL-FUNCTION is undefined.
[Condition of type UNDEFINED-FUNCTION]
Access to the default SB_INT namespace seems to be denied .
How to enable it for such cases ?
I'd like to be able to send forms to and read results from the same emacs inferior-lisp-process (sbcl) from any buffer, not just from the slime
'slime repl sbcl' buffer . Is there any way to do this?
Obviously, I can write an Emacs Lisp function to switch-to the
slime repl buffer and evaluate in that buffer.
Of course, all the above examples, eg. (eval '(symbolp '+)) ,
work fine in the slime-repl buffer. I guess there is no way
around switching-to the slime-repl buffer?
This might clarify:
In 'scratch' :
(slime-eval '(SB-INT:symbolp 'SB-INT:+) "CL-USER")^X^E
In slime output buffer:
Invalid protocol message:
The symbol "SYMBOLP" is not external in the SB-INT package.
Line: 1, Column: 26, File-Position: 26
Stream: #<SB-IMPL::STRING-INPUT-STREAM {1002A1CD63}>
(:emacs-rex (SB-INT:symbolp (quote SB-INT:+)) "CL-USER" t 78)
So, in the slime-repl buffer, I can do:
CL-USER> (PROGN (IN-PACKAGE "COMMON-LISP-USER") (+ 2 2))
4
CL-USER> (PROGN (IN-PACKAGE "SB-IMPL") (symbol-function '+))
#<FUNCTION +>
CL-USER> (PROGN (IN-PACKAGE "SB-IMPL") (symbol-function '+))
#<FUNCTION +>
SB-IMPL> (PROGN (IN-PACKAGE "SB-INT") (symbol-function '+))
#<FUNCTION +>
But if I try to run the same 'slime-eval' function in any
other buffer, eg. 'scratch' :
(slime-eval '(PROGN (COMMON-LISP-USER:IN-PACKAGE "COMMON-LISP-USER")
(symbol-function '+)) :COMMON-LISP-USER)
Invalid protocol message:
The symbol "IN-PACKAGE" is not external in the
COMMON-LISP-USER package.
Line: 1, Column: 46, File-Position: 46
I have tried ALL the likely PACKAGE names listed above in the
slime-eval with same results.
The same thing happens whether I use the 'slrepl' code snippet or just plain
slime-eval - no lisp standard syntax symbols are available. Do I need to
load the lisp syntax table or something ?
RE: can I switch to slime repl buffer and do it ? : NO ! :
(require 'slime)
(let ((slbuf (get-buffer "*slime-repl sbcl*")))
(if (eq nil slbuf)
(error "please start slime (M-x slime)")
(progn (set-buffer slbuf)(slime-eval '(+ 2 2) "COMMON-LISP-USER"))
)
)^X^E
Still results in :
The function SWANK-IO-PACKAGE::+ is undefined.
[Condition of type UNDEFINED-FUNCTION]
I am a rusty / returning LISP user and new to SBCL and slime .
I'd really like to integrate Emacs' great Editing and File management
& interacation facilitties with external CL XML & HTML generation & parsing
tools. But to start, I'd just like to get to the root of this problem...
Common Lisp symbols like + and symbolp are in the COMMON-LISP package. Short name CL. These symbols are usually not exported from package CL-USER. Thus symbolp can be referenced as cl:symbolp. These symbols are accessible in package CL-USER, but not exported from there. Thus you can also reference cl:symbolp as cl-user::symbolp -> note the two colons.
CALLING IN-PACKAGE in a form does not have an effect on the form itself, since the form is already read. Though it has an effect calling reader functions or functions like find-symbol.
CL-USER 5 > (defpackage "FOO" (:use))
#<The FOO package, 0/16 internal, 0/16 external>
CL-USER 6 > (progn (in-package "FOO")
(list 'bar (read-from-string "BAR")))
(COMMON-LISP-USER::BAR BAR) ; we now print from package "FOO"
Using SLIME-EVAL in Emacs Lisp
Best use it with a form, that reads the expression on the Common Lisp side and does not involve the Emacs Lisp reader/printer:
ELISP> (slime-eval '(cl:eval (cl:read-from-string "(+ 1 2)")) "CL-USER")
3 (#o3, #x3, ?\C-c)
ELISP> (slime-eval '(cl:eval (cl:read-from-string "'foo")) "CL-USER")
common-lisp-user::foo
But here you see that the result is brought back into Emacs Lisp via the Emacs Lisp reader - where packages don't exist.
Thus SLIME-EVAL makes very little sense as a simple remote execution interface...
This now works! Thanks !
(require 'slime)
(defun CL$ (str)
(let ((slbuf (get-buffer "*slime-repl sbcl*")))
(if (eq nil slbuf)
(error "Please start slime (M-x slime).")
(progn
(set-buffer slbuf)
(slime-eval str "CL")
)
)
)
)
(CL$ '(cl:+ 2 2))
=> 4
But I don't fully understand why I have to prepend all symbols with CL or
why this still does not work:
(slime-eval '(+ 2 2) "CL")
but this does:
(slime-eval '(cl:+ 2 2) "CL")
I thought the third parameter was meant to be made into the current package?
So why do I have to append 'cl' to every symbol .
But thanks for the help, and an otherwise great slime + sbcl .

Suppress output from print function in Lisp

I'm fairly new to Lisp, and I've run into a printing issue. I have one function which does printing to the standard output (among other things). I want to then run this function through another function where it still runs the same but instead nothing gets printed to the standard output.
Here is a simple example of what I mean. I have the following two functions described:
(defun does-printing()
(print "This goes to standard output."))
(defun run-other-function (function)
(funcall function)
(values))
Here's a dribble of what happens when I run this,
;; Dribble of #<IO TERMINAL-STREAM> started on 2014-10-05 21:49:49.
#<OUTPUT BUFFERED FILE-STREAM CHARACTER #P"example.out">
[7]> (run-other-function #'does-printing)
"This goes to standard output."
[8]> (dribble)
;; Dribble of #<IO TERMINAL-STREAM> finished on 2014-10-05 21:50:09.
Note that the printing function still prints to the standard output. It'd like to be able to suppress this printing somehow when running does-printing through run-other-function. I have tried many different variations of phrasing of my problem when searching for solutions, but nothing is getting at what I would like to do.
The simplest solution is to create an empty broadcast stream.
(with-open-stream (*standard-output* (make-broadcast-stream))
(call-some-function-1)
...
(call-some-function-n))
If a broadcast stream has no component stream all output will be discarded. Above binds the *standard-output* to such a stream. This does not cons up any data and it is portable.
You can just redirect your standard-output to some place. For example into /dev/null if you have one in your operating system. It looks like very idiomatic UNIX-way output suppressing.
Note, that you shouldn't set it to NIL, because print will signal type error in this case.
(defun does-printing()
(print "This goes to standard output."))
(defun run-other-function (function)
(with-open-file (*standard-output*
"/dev/null"
:direction :output
:if-exists :supersede)
(funcall function)
(values)))
CL-USER> (run-other-function #'does-printing)
; No value
Other option (and it may be better) is to use with-output-to-string, so you can capture this output value or just ignore it. Is think it's better, because why to do IO if we don't need it, and also it must work on any OS.
(defun run-other-function (function)
(with-output-to-string (*standard-output*
(make-array '(0)
:element-type 'base-char
:fill-pointer 0 :adjustable t))
(funcall function)
(values)))
If you doing it a lot, you can wrap it into macro or even function, to use in place of funcall.
(defun does-printing()
(print "This goes to standard output.")
"My result")
(defun funcall-with-no-output (fn)
(with-output-to-string (*standard-output*
(make-array '(0)
:element-type 'base-char
:fill-pointer 0 :adjustable t))
(funcall fn)))
CL-USER> (funcall-with-no-output #'does-printing)
"My result"
But i think macro will be more general and idiomatic for this case (may be I'm wrong).
(defmacro with-suppressed-output (&body body)
`(with-output-to-string (*standard-output*
(make-array '(0)
:element-type 'base-char
:fill-pointer 0 :adjustable t))
,#body))
So you can call many forms in with-suppressed-output.

AUCTeX: Run Compile Command n-times

I'd like to have a function that asks for a number n and executes the default compile command n-times afterwards. That is to say unlike C-c C-c (i.e. TeX-command-master) I don't want to be asked which command to run, it should select the default compile command based on the AUCTeX settings. Naturally if any error occurs the execution should stop.
I know about TeX-texify, however, this doesn't statisfy my needs because sometimes I just want emacs to run pdflatex five times indepent of what the AUCTeX parser thinks is adequate.
Any help is much appreciated!
Edit: I have looked into this a little further and using code from the above reference I have started writing a function that does this. However, it has one major flaw. Let me first give you the code:
(defcustom TeX-MultiTeX-Command "LaTeX" "Default MultiTeX command" :type 'string :group 'TeX-command)
(defun TeX-MultiTeX (n)
"Run TeX-command n-times"
(interactive "nRun TeX/LaTeX how many times: ")
(while (> n 0)
(TeX-command TeX-MultiTeX-Command 'TeX-master-file)
(setq n (- n 1))))
As you can see, I have implemented a config variable for selecting the correct compilation command. Now let me present the problem:
The compilation of the LaTeX document takes some time, however, my function instantly calls the second (and following) executions of the compile command. Maybe someone can provide help in finding a solution that checks whether compilation has finished successfully prior to executing (TeX-command TeX-MultiTeX-Command 'TeX-master-file), then executes said function or prints some error message if compilation finished with an error.
With the help of the code of the TeX-texify function I have developed a function that does what I want, the code is given below.
I'd like to thank user4815162342; although this solution is not based on his suggestion, I think his solution might be of use for a different problem. Also I'd like to thank TN, the author of TeX-texify, I shamelessly took and adapted his code for my problem. ;)
(defcustom TeX-MultiTeX-Command "LaTeX"
"Default MultiTeX command"
:type 'string :group 'TeX-command)
(defun TeX-MultiTeX-sentinel (&optional proc sentinel)
"Non-interactive! Call the standard-sentinel of the current LaTeX-process.
If there is still something left do do start the next latex-command."
(set-buffer (process-buffer proc))
(funcall TeX-MultiTeX-sentinel proc sentinel)
(let ((case-fold-search nil))
(when (string-match "\\(finished\\|exited\\)" sentinel)
(set-buffer TeX-command-buffer)
(unless (plist-get TeX-error-report-switches (intern (TeX-master-file)))
(TeX-MultiTeX TeX-MultiTeX-num-left)))))
(defun TeX-MultiTeX (n)
"Run TeX-command n-times"
(interactive "nRun TeX/LaTeX how many times: ")
(when (or (called-interactively-p 'any)
(null (boundp 'TeX-MultiTeX-num-left)))
(setq TeX-MultiTeX-num-left n))
(if (>= TeX-MultiTeX-num-left 1)
(progn
(TeX-command TeX-MultiTeX-Command 'TeX-master-file)
(setq TeX-MultiTeX-num-left (- TeX-MultiTeX-num-left 1))
(setq proc (get-buffer-process (current-buffer)))
(setq TeX-MultiTeX-sentinel (process-sentinel proc))
(set-process-sentinel proc 'TeX-MultiTeX-sentinel))))
It seems that you need a synchronous way to run TeX-command. I haven't word with TeX-command, but if it uses the compilation API, it can be made to wait for the compilation to finish, although it's not exactly obvious how to do that. Here is an example that uses compilation-finish-functions to achieve the desired effect:
(require 'cl) ; for lexical-let
(defun compile-and-wait (compilefun)
(interactive)
(lexical-let ((done nil) finish-callback)
(setq finish-callback
;; when the compilation is done, remove the callback from
;; compilation-finish-functions and interrupt the wait
(lambda (buf msg)
(setq compilation-finish-functions
(delq finish-callback compilation-finish-functions))
(setq done t)))
(push finish-callback compilation-finish-functions)
(funcall compilefun)
(while (not done)
(sleep-for .1))))
EDIT
AUC TeX is not using compilation mode to spawn TeX, so the above cannot work. Since it's still useful for other compilation buffers, I'm leaving it in the answer. Another way to implement TeX-MultiTeX is by binding TeX-process-asynchronous to nil, which should ensure that AUC TeX waits for the command to finish.

Body of defmacro not being executed

I've noticed a trend in my code of repeating the same (with-current-buffer .... over and over again so I decided to define a macro based off that macro definition of with-current-buffer - this is what I have so far:
(defmacro with-assembla-buffer(asm-buffer-name heading-str &rest body)
"Create buffer with name of ASM-BUFFER-NAME, or uses it if exists,
preps it with readonly/erase/heading - executes `body' - then puts
readonly back on, goes to beginning of buffer, and switches to it."
(with-current-buffer (get-buffer-create asm-buffer-name)
(assembla-mode)
(toggle-read-only -1)
(erase-buffer)
(insert (format "-- %s --------------------" heading-str))
(newline)
`(progn ,#body)
(toggle-read-only 1)
(goto-char (point-min))
(switch-to-buffer (current-buffer))))
The body of this is never being executed, however when it's switched to defun instead of defmacro is does work perfectly. So aside from why is body never executed, my other question is - does this make more sense as a macro than a defun?
Remember, a macro generates code. Your macro looks like it does not. Check out a macro expansion of an example call. The first step of debugging a macro is to check the macro expansion of some code.
....
(with-current-buffer (get-buffer-create asm-buffer-name)
Above: why is this as code in the macro and not as source code? This code will be executed when the macro is expanded, it won't appear in the generated code. You probably want to backquote it.
(assembla-mode)
(toggle-read-only -1)
(erase-buffer)
(insert (format "-- %s --------------------" heading-str))
(newline)
`(progn ,#body)
Above: this won't do what you want. You need to backquote ALL the code you want to generate - not just this form.

elisp mapcar + lambda + defmacro help

I am trying to generate functions using a macro:
(defmacro make-my-emacs-command-region (cmd name)
(list 'defun (intern (format "my-emacs-command-%s-%s" cmd name))
'(&optional arg)
(list 'interactive "p")
(list (intern (format "mark-%s" name)) 'arg)
(list (intern (format "my-emacs-command-%s-region" cmd))
'(region-beginning) '(region-end))))
generator:
(mapcar (lambda (a) (make-my-emacs-command-region a buffer))
'(foo bar))
But I get:
my-emacs-command-a-buffer
What am I doing wrong? How can I force to pass value of a?
A major point of lisp macros is that the arguments are not evaluated. Read up on the macro pages in the manual, specifically the expansion of macros. The macroexpand function would be of use in debugging the problem. Also, backquote might help you write the body of the macro a little more succinctly.
My elisp is a bit rusty, but until someone comes up with the actual explanation: I could get your examples to work a bit more as expected my replacing cmd with (eval cmd) (possibly same with name) in the macro definition body.
Hope this helps.