Setting up languages in emacs - emacs

So i started working with emacs as a programming editor, well i was wondering how you set the language path for a language? Im using python and its giving a error saying searching for directory: no such file or directory,python.

There is no general mechanism, it depends upon the specific language support mode.
For Python, there is the variable python-python-command. It's default value is just python, but if that doesn't work on your system, you can set it to a path (e.g. with M-x customize-variable).
You can also change the python command without changing the configuration by invoking run-python with a prefix, i.e. C-u M-x run-python.

Related

How and where to set the default load location for sbcl / slime / emacs on Ubuntu 18

I have emacs / sbcl / slime working.
I'm going through a tutorial and hit the following example:
CL-USER> (load "hello.lisp")
; Loading /home/peter/my-lisp-programs/hello.lisp
The author doesn't specify how or where he set things up to default the load location to his example.
I've tried creating the EMACSLOADPATH environment variable and have tried a setq for load-path all with no positive results.
If I load a .lisp file using the entire path as in /home/bill/lisp/hello.lisp, it load and I can run it. Id like to know how and where to set the default to "~/lisp" so I can avoid an absolute path reference.
Before the answer, EMACSLOADPATH (or load-path) isn't related to common-lisp or sbcl (which is a common-lisp implementation). It is an emacs related variable. The root of the confusion is understandable, as emacs is a tool build on its own variant of lisp, elisp, and you write elisp code to extend or configure emacs. Emacs tool has its own elisp engine that runs those elips commands. And then you start using emacs as an editor to write common-lisp code, using plugins like slime to make it easier to interact with sbcl interpreter (or any other slime compatible common-lisp interpreter, for that matter).
For the default load location of common-lisp, load function of sbcl uses *default-pathname-defaults* to form the pathname from the argument, and it is generally set to the current directory (by slime at least - check swank:set-default-directory).
However, if you want an approach similar to python's import, where the function uses a list of directories to search for, I believe there are two options to start with.
Use quicklisp or asdf, as they are equivalent to python-import, but that probably means you define a 'system' (python: 'module') and use asdf:load-system. Here is an answer for this solution: example of using external libs in common-lisp
Write a load function yourself, and search for a predefined list of directories for the file name, and form an absolute path then call cl:load with the absolute path you decide.

"illegal terminating character after a colon: #\" in portacle, though no colons in code

I've recently set up Portacle 1.3 for learning common lisp on Win 7. However, whenever I run my code I get the error, even if there is no code.
Running individual lines works fine, however. The error only shows when I run the whole file.
I tried putting some code in an EVAL function, but I believe that only accepts one argument at a time, so I couldn't run a whole program in it.
I've found a similar error in this stackoverflow page, but their code contains colons and that's where their error lies.
I think it might be an error in the code that runs mine, seeing as I get the error even if I compile with no code, however I know nothing.
The full error:
main.lisp:1:1:
read-error:
READ error during COMPILE-FILE:
illegal terminating character after a colon: #\
Line: 1, Column: 13, File-Position: 12
Stream: #<SB-INT:FORM-TRACKING-STREAM for "file [path to file]\\main.lisp" {1005F5F0D3}>
Compilation failed.
Portacle is a standalone Emacs packaged with everything needed for Common Lisp development and which uses SBCL as the Common Lisp implementation.
I believe what you do when you say 'compile the whole file' is call slime-compile-and-load-file which is bound to the key sequence C-c C-k by default. There are a lot of moving components here:
Emacs is the text editor here. It also takes care of launching all the necessary components for Common Lisp development.
Slime is one such component. It serves as interface between Emacs and your Common Lisp implementation (SBCL in this case, but supports any Lisp in theory). Basically it sends the code you wrote in Emacs to your Lisp for evaluation.
SBCL is the Common Lisp implementation. In this case it is a compiler. This is what evaluates the code it receives and spews out the answers to the user interface in Emacs, through Slime. It also 'lives', in the sense that you interact with it by modifying the state of the loaded Lisp image, keeping track of defined functions, global dynamic variables and much more. This is why you can have the REPL, and why you need Slime to interact with it.
So to debug your problem, I would try to:
Launch SBCL from the Windows shell and run a simple .lisp file to check that everything works. You can put for example (format t "~a" (lisp-implementation-type)) in a .lisp file and run it in SBCL from the shell by calling (load "...\\file.lisp"). It should return "SBCL".
Create a completely new file using Emacs (and not weird Windows programs that could mess up the files) (C-x C-f), and try to call the compile from there (C-c C-k).
And I believe you made the right choice of IDE. Portacle is arguably the simplest tool out there if you are a total beginner in Common Lisp and do not know Emacs configuration. The keybindings are a bit daunting though.

Emacs CEDET: Jumping to symbols

I have read Alex Ott's fantastic guide to CEDET for Emacs, and I think I know how to set up my EDE projects correctly.
However, when I try to jump to a local symbol (e.g. the main() function in C++) using the command semantic-complete-jump-local (C-c , j), I get the error [no match] even though I am calling this command from within the .cpp file where the symbol is defined.
Also, when I try to jump with semantic-complete-jump-global (C-c , J) to a symbol with multiple definitions on different files (e.g. multiple main() functions), CEDET complains with [not unique] but it does not give me a way to choose which symbol I want to see. The only way to find the symbol I am interested in is to cycle through all the options with <TAB> buffer by buffer until I find the one I am interested in. Is there a way to get a list of symbols from where I can choose ? Ideally, it would be great to get an autocomplete list similar to those that Emacs helm (formerly known as Anything) provides.
This is all with Emacs 24.2.1 on Linux with CEDET 1.1.
Had you tried to use semantic-ia-fast-jump command? It uses not only Semantic, but also other data sources, to calculate where to jump. I just tried it, and it correctly jumped to variable, that was declared in the parent class, 3 levels higher in hierarchy.

Reliably navigating to correct function definition with tags in Emacs

So I've been using Exuberant ctags with Emacs to navigate my way around a Linux kernel driver I'm trying to understand. I just spent a day debugging a problem which boiled down to me reading the wrong function definition, because foo() was defined (differently) in two separate files, and using M-. to navigate to the function definition took me to the irrelevant one of the two possible options. Is there a way to reliably navigate to a function definition in Emacs? I've given Vim a try with C-] and that seems to take me to the correct function definition, but I'm not normally a Vim user. So I'm looking for an Emacs specific solution, not a "switch from Emacs to Vim".

Best way to customize auto-formatting/auto-indenting in vim for Common Lisp

I would like to know the best way to customize auto-formatting/auto-indenting in vim for Common Lisp.
Auto-formatting (I usually do this by typing '==' in command mode per line) works very well for the base lisp language in vim (e.g., defmacro, defun, lambda, if, with-output-to-string), but any time that new language constructs are defined (e.g., using macros), I find that the formatting for the new construct is often not what I'd like it to be.
For example, here's how vim formats 'when (standard lisp construct) and 'awhen (commonly-used anaphoric version of 'when; not part of lisp standard)
(when 'this
(process 'this))
(awhen 'this
(process it))
I would like 'awhen to auto-format like 'when. Any ideas how I can do this?
Edit: Thanks Gilligan and Tamas for the Slimv recommendation. As a test, I downloaded MacVim (will need this working with terminal vim, but that's a different problem) and slimv, rsynched the slimv download into ~/.vim, launched MacVim, and loaded a .lisp file.
I then started up the lisp server (done through a GUI with MacVim), which loaded up my default lisp executable and core file.
And* since my core file is already loaded with the language extensions that I commonly use (awhen being one of them), awhen formatted correctly right out of the box.
I really like this solution. Instead of [1] having to learn how to tell vim to indent particular functions properly, and [2] writing the code that does this explicitly for each language extension that I define, and [3] updating that code every time I add a new language construct. Instead I leverage slimv to do the formatting for me. And slimv can 'learn' new language extensions, as long as those macros are already loaded into the lisp core that the server session is using. Pretty slick!
I have found that this works well for a particular class of language extensions. Usually ones defined as a macro, using the &body keyword. This seems to 'do the right thing' most of the time, but there are macros I use that still don't properly auto-format. Although I'd say that this is more likely to be an issue with how the macro is written (non-standard language extension) than anything else.
So, this solution works well for me for most cases, and I didn't have to code (and maintain) anything. Great stuff!
This might not be a direct answer to your question but I strongly suggest that you install
the slimv plugin: http://www.vim.org/scripts/script.php?script_id=2531
Its a great plugin which integrates SLIME functionality into vim and besides many other things it also comes with an improved indentation for clisp&clojure. It won't indent awhen the way you want though.
For those who are looking for this topic and don't want to run Slimv, because they aren't working with Common Lisp or other reasons, here is the scoop.
Vim's Lisp indentation is not like that for other languages; it has a special "Lisp mode". This mode is turned on by
:set lisp
which is done automatically for .lisp files. Lisp mode isn't a Vim invention; classic Vi implementations have a Lisp mode turned on with :set lisp. (It's not described by POSIX, unfortunately).
Vim's Lisp mode has a simple mechanism for recognizing forms that require operator-style indentation: namely, there is a parameter called lispwords which holds a comma-separated list of identifiers.
You can prove to yourself that this is the identifier list which is used, even when you're editing a Common Lisp .lisp file with syntax highlighting and all. Simply do :set listwords[TAB] and edit the list to remove something from it, such as defun. Then try to reindent a defun: you will see the function-style indentation now instead of the operator-style.
The syntax highlighting support for Common Lisp is separate from Lisp mode's lispwords parameter; it has its own list of identifiers. For example, in Vim 7.3 if you enter this:
(symbol-macrolet ((foo bar))
you get indented out to here!)
This is in spite of the fact that symbol-macrolet is recognized and colored. Why? It's because symbol-macrolet does not appear in the rather scanty lispwords list, whereas it does appear in the lisp.vim syntax highlighting definition file.
The upshot is that you can cob together some script which scans your directory of .lisp files for macros and generates a set lispwords=... command that is placed into a directory .vimrc.
Or if you are working on a custom Lisp dialect, you can just make its Vim syntax highlighting file customize lispwords when it loads.
Here is an implementation oversight: the lispwords option has no local value; you cannot use setlocal lispwords ... to give it a buffer-specific value. In other words, it appears that (at least in the Vim 7.3 I'm using under Ubuntu) you can't have two or more buffers open holding different dialects of Lisp with different identifiers for indentation. The default contents of lispwords contains a smattering of Lisp and Scheme symbols to try to be a kind of "one size almost fits all" solution.
If you filetype is 'lisp' then I think you need to add indenting rules for your special case in the 'lisp.vim' file in the '/vim7x/indent' directory. You can find a bit more info in help at :h indent-expr and :h indentexpr.
Someone may be able to tell you better, but I believe the default lisp.vim indent file basically does nothing because the built-in function lispindent() is used to get indent values. You will want to:
(1) set function used to get indent values (i.e., indentexpr) to a function in your own indent/lisp.vim file, e.g., GetLispIndent().
(2) in your your GetLispIndent() function you will use lispindent() to get indent values to return for all lines except your special case. See other languages' indent files and read the docs to get an idea for how indentexpr works, e.g, java.vim.
#Kaz's answer is completely correct, but they don't go all the way to answering the original question. Vim's lispwords config string is a comma-delimited list of words; when any of the words in lispwords is found at the beginning of an S-expression, Vim will change the way that S-expression is indented. In other words, it defines the "standard lisp constructs" to which the OP refers. If you view your current lispwords config with :set lispwords, you'll see "when" is included, but "awhen" is not, resulting in the following indentation:
(when 'this
(process 'this))
(awhen 'this
(process it))
To fix this, simply add "awhen" to the config string somewhere in your config, like so:
set lispwords+=awhen,
The trailing comma isn't strictly necessary, but the default value includes it, and is probably wise in case you or a plugin modifier elsewhere. That would turn the original formatting into this:
(when 'this
(process 'this))
(awhen 'this
(process it))
(Tested on my current installation of Vim 9.0)
Note that, as #Kaz points out, this config string is universal, so if you have different dialects of lisp their indentation will all be controlled by this setting. Vim is pretty good about auto-detecting lisps, but you may need so :set lisp if it doesn't recognize your filetype or dialect.