I have lua function which accept the arguments. I want to get the name of the argument so that I can log the argument along with error.
Any idea how to get argument name in lua?
Use debug.getlocal.
Related
I have Avoid redundant argument values. warning in my code, and it is okay for that moment. Is there any #ignore option in dart for that?
DON'T pass an argument that matches the corresponding parameter's default value.
I have written a simple function named is_zero in Erlang which checks if the argument to the function is zero. The code is as follows.
-module(match).
-export([is_zero/1]).
% defining a function named is_zero
% this is a function with two clauses
% these clauses are matched sequentially
is_zero(0) ->
true;
is_zero(X) ->
false.
As I try to compile the code using c(match).(the file is also named as match.erl) it returns a warning saying variable "X" is unused.
If I run is_zero(0). in spite of the warning, the shell throws an exception error saying undefined shell command is_zero/1
What am I doing wrong?
I cannot think of any rectification neither can I find any advice that will help.
Functions in Erlang are defined inside modules. To distinguish functions from different modules, you need to prepend the module name to a function. In this case, you need to run match:is_zero(0). Instead of just is_zero(0)..
To avoid the warning saying variable "X" is unused, use the underscore variable:
is_zero(_) ->
false.
Note that variable names can be useful even if unused, to improve readability. If you want to name your variable and still avoid the compiler warning, prepend the underscore to the name:
is_zero(_Num) ->
false.
I have a generator called with yo generator:module [ModuleName] .
I want to handle the error when ModuleName argument is undefined and still be able to use generator:module --help without arguments.
First, you'll need to make the arguments non required.
Then if the argument was not provided, handle the case yourself as you see fit.
I've been trying to write a script-fu script for GIMP 2.6+ that uses one of the built-in script-fu methods, namely the script-fu-add-bevel method. My problem is that whenever I call it, either in the console or in my script, I get:
Error: Procedure execution of gimp-drawable-type-with-alpha failed on invalid input
arguments: Procedure 'gimp-drawable-type-with-alpha' has been called with an
invalid ID for argument 'drawable'. Most likely a plug-in is trying to work on a layer that
doesn't exist any longer.
This is really strange because I can clearly see by calling gimp-image-get-active-drawable with my image ID as the parameter that the layer ID that I'm passing to the script-fu method exists. The script is erroring while calling gimp-drawable-type-with-alpha, but I can call this method with the same ID in the console with no error. How can I fix this problem?
From this forum post, I learned that when calling a script-fu method, you shouldn't pass in the run-mode argument. This is done behind the scenes, and if you pass anything for that value, it will be interpreted as the second argument! This means that every argument you send in will be one parameter off, and it's only a matter of time before the script crashes.
So calling script-fu-add-bevel from another script-fu would look something like this:
(script-fu-add-bevel img layer bevel-width FALSE FALSE)
I have a LUA CLI which takes in the lua command,
Something like this
(lua)> #
Now here inorder to execute the lua file I run the command
(lua)> # dofile("a.lua")
I want a command which will execute the file and also pass a argument to it.
Now here I want to pass a argument to the "a.lua" file which will take this argument and call one more lua file, and this 2nd lua file is called according to the argument, So, I need to parse this argument.
Please, can somebody tell me about the parsing commands that will be used in a.lua. I mean what are the functions to be used to parse it.
Please, can somebody tell me how to pass a argument to this file "a.lua".
Now here inorder to execute the lua file I run the command
This is generally not how you execute Lua files. Usually, if you have some Lua script, you execute it with this command: lua a.lua. You don't type lua and then use the interface there to execute it.
Using a proper command line to execute the script, you can pass string parameters to the file: lua a.lua someParam "Param with spaces". The a.lua script can then fetch these parameters using the standard Lua ... mechanic:
local params = {...}
params[1] -- first parameter, if any.
params[2] -- second parameter, if any.
#params -- number of parameters.
However, if you insist on trying to execute this using your method of invoking the interpreter (with lua) and typing commands into it one by one, then you can do this:
> GlobalVariable = assert(loadfile(`a.lua`))
> GlobalVariable(--[[Insert parameters here]])
However, if you don't want to do it in two steps, with the intermediate global variable, you can do it in one:
> assert(loadfile(`a.lua`))(--[[Insert parameters here]])