Editing RS:LUA (section)

===Use the debug console===
The debug console lets you test code while you're working on it. This saves you a lot of time. It also lets you avoid saving unecessary revisions just to see if your code is working. Instead you'll only be saving known working code after you're done with adding a feature. Don't wait too long though, in case your power or internet goes out.

You can test expressions such as: <pre>= 2+2</pre> which will return <pre>4</pre> as you'd expect. 

You can also call into any function that is ''visible'' from outside. If you defined this function as part of for instance table p which you're then returning to Scribunto, you can call into this function from the debug console:

<syntaxhighlight lang='lua'>
local p = {}

function p.calculate(num)
    return num + 2
end

return p
</syntaxhighlight>

<pre>= p.calculate(3)</pre> or <pre>mw.log( p.calculate(3) )</pre> yields <pre>5</pre>

If this function were instead returning a table you could inspect it like so:

<syntaxhighlight lang='lua'>
local p = {}

function p.calculate2(num)
    return { num + 1, num + 2}
end

return p
</syntaxhighlight>

<pre>mw.logObject( p.calculate2(3) )</pre>

Sometimes you might not be interested in the output and only want to check if a function works. In the above example you could have used one of the following for that:

<pre>= #p.calculate2(3)</pre>
<pre>= type(p.calculate2(3))</pre>

Of course calling any Lua function from the outside, expects the function to only take one argument, the frame object, which we can't provide in the debug console, so we have to work around that. This is usually done by providing two entry-point functions, one which takes the frame object, grabs the arguments from it an passes it on to the ''real'' function like so:

<syntaxhighlight lang='lua'>
local p = {}

function p.calculate(frame)
    local args = frame:getParent().args

    return p._calculate(args)
end

function p._calculate(args)
    local num = args[1]

    return num + 2
end

return p
</syntaxhighlight>

Normal invocation of the module will use the p.calculate() function, but now you can debug the output from the real p._calculate() function in the debug console like so:

<pre>= p._calculate({3})</pre>