Is there a way to define built-in functions in Maxima?
I have a function which I would like to use in several .wxm files without defining them in every file.
You can put the functions in a file, let's say it is named foo.mac, and then call load("foo.mac") to load the functions into Maxima or wxMaxima.
Note that load needs to be able to find foo.mac. If foo.mac is not in one of the usual folders, you can help load find it in a few different ways:
(1) State the fully-qualified path, e.g. load("/Users/myfolder/myfunctions/foo.mac").
(2) Put your folder on the list of folders to search and then call load. E.g.
push ("/Users/myfolder/myfunctions/###.mac", file_search_maxima);
load ("foo.mac");
Note that file_search_maxima is a global variable which tells all the folders in which load searches.
Related
I have rule A implemented with a macro that uses declare_directory to produce a set of files:
output = ctx.actions.declare_directory("selected")
Names of those files are not known in advance. The implementation returns the directory created by declare_directory with the following:
return DefaultInfo(
files = depset([output]),
)
Rule A is included in "srcs" attribute of rule B. Rule B is also implemented with a macro. Unfortunately the list of files passed to B implementation through "srcs" attribute only contains the "selected" directory created by rule A instead of files residing in that directory.
I know that Args class supports expansion of directories so I could pass names of all files in "selected" directory to a single action. What I need, however, is a separate action for every individual file for parallelism and caching. What is the best way to achieve that?
This is one of the intended use cases of directory outputs (called TreeArtifacts in the implementation), and it's implemented using ActionTemplate:
https://github.com/bazelbuild/bazel/blob/c2100ad420618bb53754508da806b5624209d9be/src/main/java/com/google/devtools/build/lib/actions/ActionTemplate.java#L24-L57
However, this is not exposed to Starlark, and has only a couple usages currently, in the Android rules AndroidBinary.java and C++ rules CcCompilationHelper.java. The Android rules and C++ rules are going to be migrated over to Starlark, so this functionality might eventually be made available in Starlark, but I'm not sure of any concrete timelines. It would probably be good to file a feature request on Github.
I want to make a small "library" to be used by my future maxima scripts, but I am not quite sure on how to proceed (I use wxMaxima). Maxima's documentation covers the save(), load() and loadFile() functions, yet does not provide examples. Therefore, I am not sure whether I am using the proper/best way or not. My current solution, which is based on this post, stores my library in the *.lisp format.
As a simple example, let's say that my library defines the cosSin(x) function. I open a new session and define this function as
(%i0) cosSin(x) := cos(x) * sin(x);
I then save it to a lisp file located in the /tmp/ directory.
(%i1) save("/tmp/lib.lisp");
I then open a new instance of maxima and load the library
(%i0) loadfile("/tmp/lib.lisp");
The cosSin(x) is now defined and can be called
(%i1) cosSin(%pi/4)
(%o1) 1/2
However, I noticed that a substantial number of the libraries shipped with maxima are of *.mac format: the /usr/share/maxima/5.37.2/share/ directory contains 428 *.mac files and 516 *.lisp files. Is it a better format? How would I generate such files?
More generally, what are the different ways a library can be saved and loaded? What is the recommended approach?
Usually people put the functions they need in a file name something.mac and then load("something.mac"); loads the functions into Maxima.
A file can contain any number of functions. A file can load other files, so if you have somethingA.mac and somethingB.mac, then you can have another file that just says load("somethingA.mac"); load("somethingB.mac");.
One can also create Lisp files and load them too, but it is not required to write functions in Lisp.
Unless you are specifically interested in writing Lisp functions, my advice is to write your functions in the Maxima language and put them in a file, using an ordinary text editor. Also, I recommend that you don't use save to save the functions to a file as Lisp code; just type the functions into a file, as Maxima code, with a plain text editor.
Take a look at the files in share to get a feeling for how other people have gone about it. I am looking right now at share/contrib/ggf.mac and I see it has a lengthy comment header describing its purpose -- such comments are always a good idea.
For principiants, like me,
Menu Edit:configure:Startup commands
Copy all the functions you have verified in the first box (this will write your wxmaxima-init.mac in the location indicated below)
Restart Wxmaxima.
Now you can access the functions whitout any load() command
I'm trying to make a mod for the game Don't Starve Together, which makes use of Lua. For this reason, I can't modify their source variables/files.
In order to try to modify the world generation, I need to access a local table that was instantiated in another file (the file is called "levels.lua"). The variable name is "levellist". Is there a way to access the variable so that I can add certain elements to the table?
Namely, I want to add {"task_set", "cave_custom"} to levellist[DST_CAVE].overrides.
If someone could help or even just tell me if this is possible or not, that would be great. Thanks!
What you are trying to do simply doesn't make sense. Local variables are accessible only from the scope it was defined in, and it's nested scopes. There is no, normal, way to change it from different scopes, let alone an entirely different script.
If you want variables that all your scripts use, use globals.
Of course you can't get to local variables (i.e. "pointers") used by another function, save for obscure debug methods that are rarely exposed to user sandbox, but you don't need to. Because you do not want to modify some local variable (i.e. make it point to another table for example), but get to some table and modify value inside it. So you just need to find any place where it is exposed to you in any way.
You should somehow edit in relevant content in your question because it is PITA to Alt-Tab back and forth to your files. According to structure from comments/chat AddLevel(LEVELTYPE.SURVIVAL, ...) inserts an entry into levellist[LEVELTYPE.SURVIVAL] table. If you check levels.lua you can also see that it returns table with sandbox_levels assigned exactly to this.
So:
local levels = require "levels"
print(levels.sandbox_levels)
-- Will print "table: SOMENUMBERS" - i.e. address of levellist[LEVELTYPE.SURVIVAL]
You now can iterate it with for idx = 1, #levels.sandbox_levels or ipairs and find entry belonging to "DST_CAVE". I can't tell how field with ID will be called or how it will be structured because data is preprocessed with function Level before inserting that you did not include in the files you posted.
As others have suggested, this may not be your best strategy.
But depending on your environment, it may be possible to abuse some more esoteric features of the runtime to let you indirectly modify values that aren't "yours". Have a look at debug.sethook and setfenv.
I'm trying to use phpBB3 (forum app) along with ZF2. For that, I have to include a file from the phpBB3. In theory this is as simple as:
include('/path/to/phpbb3/common.php');
$user->session_begin(); //$user is defined in common.php file
In common.php a lot of globals are defined, and after that are required some files which are using those globals.
In ZF2 simply including the common.php would not work, because the scope of the globals will not span over the required files, so I tried a little trick:
//in Application/Forum/Service
public function callForumAPI(){
$zf_dir = getcwd();
chdir('/var/www/html/phpBB3');
include('common.php');
$user->session_begin();
chdir($zf_dir);
}
Neither in this case the scope of the global variables didn't span over the required files, so all the globals where NULL in those files.
How could I solve this issue?
I consider 2 main problems:
1. Loading resources
I dont know if you changed the code of phpBB3, since if you dont, your problem is other.
Phpbb3, as many systems, doesnt let you access directly to any file, you have to go through index.php. As you can see in common.php
if (!defined('IN_PHPBB'))
{
exit;
}
IN_PHPBB is defined in index.php, so you can simply use
Also, common.php and other files, makes use of $phpbb_root_path, that is defined in index.php.
So, at least, when you are going to include common.php you need
$zf_dir = getcwd();
chdir('/var/www/html/phpBB3');
define('IN_PHPBB', true);
$phpbb_root_path = (defined('PHPBB_ROOT_PATH')) ? PHPBB_ROOT_PATH : './';
include('common.php');
...
chdir($zf_dir);
probably there are some other things you have to take care about.
2. Variable scopes
Also, consider than in PHP, like in almost every language, a variable declared inside a function, is considered local, and will be undefined outside that function. So for sure, if you do that inside callForumAPI(), you wont have any variable outside, and moreover, depending on where you are doing that includes...it could be actually inside a function, no matter you can notice it or not, since ZF2 is a framenwork with a complex, non-obvius architecture.
So, what i recomend, as soon as you load the file, is to use the ZF2 service manager to store all the variables and object than you would use in your application. This is a good measure even if you didnt need it,since this way you can have everything integrated as much as possible, it is important to minimize and localize access to phpbb3, since it is not meant to be a library, maintenance could be tricky, so if everyhing is in the same file, and then you create your own internal api through the service manager, it will more encapsulated and nicer. I assume you already know how to do this, if you dont, just let me know.
try this, and tell me if its enough or we need more research
I'm currently writing some functions that are related to lists that I could possibly be reused.
My question is:
Are there any conventions or best practices for organizing such functions?
To frame this question, I would ideally like to "extend" the existing lists module such that I'm calling my new function the following way: lists:my_funcion(). At the moment I have lists_extensions:my_function(). Is there anyway to do this?
I read about erlang packages and that they are essentially namespaces in Erlang. Is it possible to define a new namespace for Lists with new Lists functions?
Note that I'm not looking to fork and change the standard lists module, but to find a way to define new functions in a new module also called Lists, but avoid the consequent naming collisions by using some kind namespacing scheme.
Any advice or references would be appreciated.
Cheers.
To frame this question, I would ideally like to "extend" the existing lists module such that I'm calling my new function the following way: lists:my_funcion(). At the moment I have lists_extensions:my_function(). Is there anyway to do this?
No, so far as I know.
I read about erlang packages and that they are essentially namespaces in Erlang. Is it possible to define a new namespace for Lists with new Lists functions?
They are experimental and not generally used. You could have a module called lists in a different namespace, but you would have trouble calling functions from the standard module in this namespace.
I give you reasons why not to use lists:your_function() and instead use lists_extension:your_function():
Generally, the Erlang/OTP Design Guidelines state that each "Application" -- libraries are also an application -- contains modules. Now you can ask the system what application did introduce a specific module? This system would break when modules are fragmented.
However, I do understand why you would want a lists:your_function/N:
It's easier to use for the author of your_function, because he needs the your_function(...) a lot when working with []. When another Erlang programmer -- who knows the stdlb -- reads this code, he will not know what it does. This is confusing.
It looks more concise than lists_extension:your_function/N. That's a matter of taste.
I think this method would work on any distro:
You can make an application that automatically rewrites the core erlang modules of whichever distribution is running. Append your custom functions to the core modules and recompile them before compiling and running your own application that calls the custom functions. This doesn't require a custom distribution. Just some careful planning and use of the file tools and BIFs for compiling and loading.
* You want to make sure you don't append your functions every time. Once you rewrite the file, it will be permanent unless the user replaces the file later. Could use a check with module_info to confirm of your custom functions exist to decide if you need to run the extension writer.
Pseudo Example:
lists_funs() -> ["myFun() -> <<"things to do">>."].
extend_lists() ->
{ok, Io} = file:open(?LISTS_MODULE_PATH, [append]),
lists:foreach(fun(Fun) -> io:format(Io,"~s~n",[Fun]) end, lists_funs()),
file:close(Io),
c(?LISTS_MODULE_PATH).
* You may want to keep copies of the original modules to restore if the compiler fails that way you don't have to do anything heavy if you make a mistake in your list of functions and also use as source anytime you want to rewrite the module to extend it with more functions.
* You could use a list_extension module to keep all of the logic for your functions and just pass the functions to list in this function using funName(Args) -> lists_extension:funName(Args).
* You could also make an override system that searches for existing functions and rewrites them in a similar way but it is more complicated.
I'm sure there are plenty of ways to improve and optimize this method. I use something similar to update some of my own modules at runtime, so I don't see any reason it wouldn't work on core modules also.
i guess what you want to do is to have some of your functions accessible from the lists module. It is good that you would want to convert commonly used code into a library.
one way to do this is to test your functions well, and if their are fine, you copy the functions, paste them in the lists.erl module (WARNING: Ensure you do not overwrite existing functions, just paste at the end of the file). this file can be found in the path $ERLANG_INSTALLATION_FOLDER/lib/stdlib-{$VERSION}/src/lists.erl. Make sure that you add your functions among those exported in the lists module (in the -export([your_function/1,.....])), to make them accessible from other modules. Save the file.
Once you have done this, we need to recompile the lists module. You could use an EmakeFile. The contents of this file would be as follows:
{"src/*", [verbose,report,strict_record_tests,warn_obsolete_guard,{outdir, "ebin"}]}.
Copy that text into a file called EmakeFile. Put this file in the path: $ERLANG_INSTALLATION_FOLDER/lib/stdlib-{$VERSION}/EmakeFile.
Once this is done, go and open an erlang shell and let its pwd(), the current working directory be the path in which the EmakeFile is, i.e. $ERLANG_INSTALLATION_FOLDER/lib/stdlib-{$VERSION}/.
Call the function: make:all() in the shell and you will see that the module lists is recompiled. Close the shell.
Once you open a new erlang shell, and assuming you exported you functions in the lists module, they will be running the way you want, right in the lists module.
Erlang being open source allows us to add functionality, recompile and reload the libraries. This should do what you want, success.