I'd like to use Code.format_string!/2 of Elixir 1.6 in my escript code. For the compatibility between different Elixir versions, I planed to use function_exported?/3 to see if format_string is supported in user's environment. But I found it doesn't work as expected. It always returns false in Macbook(Elixir is 1.6), but it can be called normally.
I created a demo to describe this problem:
https://github.com/tony612/escript_export
function_exported?/3 assumes the module is already loaded in memory. You probably want to do this:
if Code.ensure_loaded?(Code) and function_exported?(Code, :format_string!, 2) do
...
Related
In short
How to force python interpreter to load the most up-to-date code version of my module everytime I make some changes in the module code?
Or at least reload the last modified version by typing
>>> from myModule import *
into console, without necessity to restart whole python console and setup everything again and again anytime I make some changes? This is extremely unpleasant behavior for debugging.
--------- LONGER STORY -----------
I tried to delete the .pyc file, and import it again - but it has no effect. It does't even create .pyc file again - so I expect it completely ignore my "import" command if the module is already loaded.
this also does not help:
>>> mymodule.myfunc() # the old version
>>> del myModule # unload mymodle from python conole / interpeter
... # now I removed .pyc
... # now I make some modifications in mymodule.myfunc() code
>>> mymodule.myfunc() # module is unknonwn, ... OK
>>> import myModule # try to load modified version
>>> mymodule.myfunc() # stil the old version :(((((, How it can remember?
I have tried also Spyder where is this feature called "User Module Deleter (UMD)"
http://pythonhosted.org/spyder/console.html#reloading-modules-the-user-module-deleter-umd
which I thought should do exactly this, but it seem it doesn't (Yes, I checked that it is turned on).
Maybe I'm missing something - can somebody explain me how is it supposed to be used?
Is this somehow affected by the fact that the imported module is not in "Working directory" but in PYTHONPATH ?
(Spyder dev here) I think at the moment you are not able to reload a module directly in the console (but we are considering to change this in the future).
The idea about UMD is that it will reload your modules but only if you run a file from the editor that imports them. It doesn't work if you want to reload them directly in the console.
Let's say you developed a module, then you are probably using it in a different script that (most likely) you'll be writing in our editor and send it to run to our console. UMD is a little bit of magic that reloads it for you when that happens.
Maybe useful for others. In Spyder 3.0.0, the modules can be reloaded by,
Tools -> Update modules names list.
It worked for me.
I've been learning Ruby/Rails with vim. Tim Pope's rails.vim seems like a really good tool to traverse files with, but I keep getting these pesky "E345 can't find file in path" errors. I'm not vim expert yet, so the solution isn't obvious. Additionally, I've tried this and it doesn't apply to my problem.
As an example of the problem. I have a method format_name defined in app/helpers/application_helper.rb and it is used in app/helpers/messages_helper.rb. Within the latter file I put my cursor over the usage of format_name and then hit gf and I get that error. Similar disfunction with commands like ]f and [f
However, it works sometimes. I was able to gf from user to the app/models/user.rb
Ideas?
I think that is a limitation of rails.vim. It does not support “finding” bare methods. Supporting something like that would require one of the following:
an exhaustive search of all the source files for each “find” request
(which could be expensive with large projects),
“dumb” indexing of method names
(e.g. Exuberant Ctags and gControl-]; see :help g_CTRL-]), or
smart enough parsing of the code to make a good guess where the method might be defined
(which is hard to do properly).
If you know where the method is, you can extend many of the navigation commands with a method name:
:Rhelper application#format_name
But, you do not have to type all of that in. Assuming the cursor is on format_name you can probably just type:RhTabspaceappTab#Control-R Control-W (see :help c_CTRL-R_CTRL-W).
The include directive is usually used for a .hrl file at the top of an .erl file.
But, I would like to use include from the Erlang console directly.
I am trying to use some functions in a module. I have compiled the erl file from the console. But, the functions I want to use do not work without access to the hrl file.
Any suggestions?
"But, the functions I want to use do not work without access to the hrl file."
This can't be true, but from this I'll take a shot at guessing that you want access to records in the hrl file that you don't (normally) have in the shell.
If you do rr(MODULE) you will load all records defined in MODULE(including those defined in an include file included by MODULE).
Then you can do everything you need to from the shell.
(Another thing you may possibly want for testing is to add the line -compile(export_all) to your erl file. Ugly, but good sometimes for testing.)
Have you tried the compile:file option? You can pass a list of modules to be included thus:
compile:file("myfile.erl", [{i, "/path/1/"}, {i, "/path/2/"}])
It's worth nothing that jsonerl.hrl doesn't contain any functions. It contains macros. As far as I know, macros are a compile-time-only construct in Erlang.
The easiest way to make them available would be to create a .erl file yourself that actually declares functions that are implemented in terms of the macro. Maybe something like this:
-module(jsonerl_helpers).
-include("jsonerl.hrl").
record_to_struct_f(RecordName, Record) ->
?record_to_struct(RecordName, Record).
... which, after you compile, you could call as:
jsonerl_helpers:record_to_struct_f(RecordName, Record)
I don't know why the author chose to implement those as macros; it seems odd, but I'm sure he had his reasons.
I have tried :
c(module_name).
: but this only works from the shell, and gives an error when I try to run it from within a module.
If you want exactly that behaviour, c:c(module_name) will call the same function called by the shell. I would hesitate to put code that calls user_default (c) functions in production code, so you might want to look at the source for the function and replicate it in your own code so you don't get bitten by a behaviour change in a future erlang release.
You might want to have a look to the compile module and to the compile:file/2 function in specific.
I'm using a closed-source application that loads Lua scripts and allows some customization through modifying these scripts. Unfortunately that application is not very good at generating useful log output (all I get is 'script failed') if something goes wrong in one of the Lua scripts.
I realize that dynamic languages are pretty much resistant to static code analysis in the way C++ code can be analyzed for example.
I was hoping though, there would be a tool that runs through a Lua script and e.g. warns about variables that have not been defined in the context of a particular script.
Essentially what I'm looking for is a tool that for a script:
local a
print b
would output:
warning: script.lua(1): local 'a' is not used'
warning: script.lua(2): 'b' may not be defined'
It can only really be warnings for most things but that would still be useful! Does such a tool exist? Or maybe a Lua IDE with a feature like that build in?
Thanks, Chris
Automated static code analysis for Lua is not an easy task in general. However, for a limited set of practical problems it is quite doable.
Quick googling for "lua lint" yields these two tools: lua-checker and Lua lint.
You may want to roll your own tool for your specific needs however.
Metalua is one of the most powerful tools for static Lua code analysis. For example, please see metalint, the tool for global variable usage analysis.
Please do not hesitate to post your question on Metalua mailing list. People there are usually very helpful.
There is also lua-inspect, which is based on metalua that was already mentioned. I've integrated it into ZeroBrane Studio IDE, which generates an output very similar to what you'd expect. See this SO answer for details: https://stackoverflow.com/a/11789348/1442917.
For checking globals, see this lua-l posting. Checking locals is harder.
You need to find a parser for lua (should be available as open source) and use it to parse the script into a proper AST tree. Use that tree and a simple variable visibility tracker to find out when a variable is or isn't defined.
Usually the scoping rules are simple:
start with the top AST node and an empty scope
item look at the child statements for that node. Every variable declaration should be added in the current scope.
if a new scope is starting (for example via a { operator) create a new variable scope inheriting the variables in the current scope).
when a scope is ending (for example via } ) remove the current child variable scope and return to the parent.
Iterate carefully.
This will provide you with what variables are visible where inside the AST. You can use this information and if you also inspect the expressions AST nodes (read/write of variables) you can find out your information.
I just started using luacheck and it is excellent!
The first release was from 2015.