F# What is this [<something>]? - f#

I have come across something like this:
[<Activity (Label = "setView", MainLauncher = true)>]
several times and i have been wondering what is [<something>] and what does it do? I would gladly read up on it but i can't since i have no clue what it is called or what it does?

Related

Avalonia: How to display PNG as image?

I haven't seen an F# example of accomplishing this, or any examples similar enough to what I am trying to do, so hopefully a solution here will be helpful to others.
I am using Avalonia with F# to build a simple UI. I want to include images in my UI, but have spent hours looking at documentation and examples and everything I've seen looks to be overcomplicated (maybe it really is just that complicated?).
I am creating an image like:
let b = (Avalonia.Media.Imaging.Bitmap #"C:\Images\icon.png")
Image.create [
Image.source b
]
This just displays nothing. What am I missing here?
To add more detail to my comment above, here's what works for me:
let view =
Component(fun ctx ->
let b = new Avalonia.Media.Imaging.Bitmap("Small.png")
Image.create [
Image.source b
]
)
Result is:

wxMaxima: how to get decimal number results?

This should be easy but I am struggling on that.
I googled already but nothing seems to work.
(I am using wxMaxima 15.08.1 on Windows)
My example code looks like this:
kill (all);
numer:true;
sigma_z: 1000.0$ /*[N/mm²]*/
sigma_b_zul : simga_z*0.7;
sigma_b_zul : simga_z*0.7, numer;
sigma_b_zul : simga_z*0.7, numer:true;
float(sigma_b_zul);
the output is every time:
0.7 simga_z
the next cell looks like:
d_d: 1000$ /*dfd*/
sigma_g_f_d: d_d * 0.7;
the result is:
7.0E+2
I am completely clueless why maxima behaves like this. Can anyone help?
The variable you define is
sigma_z: 1000.0$ /*[N/mm²]*/
but then you call
simga_z*0.7;
Please, notice the difference between sigma_z and simga_z.

WoW API / Lua - Math.Random(#,#)

Always feel like I'm making something far more complicated than it has to be. I'm currently playing around with the WoW addon, Tongues, in hope of make a custom dialect filter - which is quite easy of course, very noob-friendly. At this point, there is one thing I want to accomplish-- something of which feels to have the implications far beyond this -- that is just novelty, but before I give up completely (lots of hours trying different things with no headway) I was hoping someone could come by, get a cheap laugh and perhaps help me fix this if they understand my point. And who knows, posting this new helpless questions might bump me up to being able to finally upvote!
Tongues.Affect["Drunk"] = {
["substitute"] = {
[1] = merge({
{ ["([%a]+)(%A*)$"] = "%1 ...hic!"},
Tongues.Affect["Slur"]["substitute"][1]
});
};
["frequency"] = 100;
};
What this does is simply add on the "...hic!" to sendchatmessage(); I believe it is. The frequency part seems completely broken and only the GUI slider in the game matters for that. What I was hoping to accomplish was to repurpose this and make the "...hic!" an actual randomized word. Since the mod itself handles the chance that it happens, I figured all that is needed left is to replace the string with a function=X. It's, of course, intensely way over my head, but despite checking the Lua of several mods, nothing feels like "it will fit."
The best I could come up with,
Tongues.Affect["TESTAFFECT"] = {
["substitute"] = {
[1] = merge({
{ ["([%a]+)(%A*)$"] = function(b)
local rand = Math.Random(1,2)
if (rand == 1) then
b = "test1"
return b
elseif (rand == 2) then
b = "test2"
return b
end
end
Leaves a gloriously useless message in the error mod BugSack - of course my attempt is wrong, but there's no way to know how!
I'm assuming this is enough information - as I said, very user friendly mod without any need to understand how it really works (Although I'd love to ready study it after this "project")
Anyone? Regardless, thank you for your time in simply even reading this far.
Update: Downvotes, okay! That's cool too. A little unpredictable, but sure. The error is as follows
15x Tongues\Core\dialects.lua:172: attempt to index field 'Affect' (a nil value)
Tongues\Core\dialects.lua:172: in main chunk
Locals:
175 in dialects.lua is
Tongues.Affect["Wordcut"]["substitute"][1],
Which has nothing to do with what I'm trying to accomplish, and works just fine.
Sorry that my question was an inconvenience. I asked to the best of my ability and the best of my ability to articulate the question proved to be less then stellar. The example codes I had provided were the only way I could articulate showing what I was trying to do.
I was misinterpreting the error frame and discovered that behind the useless stack that calls an error where there is, in fact, none, is a stack that calls the error in syntax at the time that broke it.
I'm sharing my results, regardless if the community finds this useless. I learned a tremendous amount from this personally, which is the only incentive in that I asked for help.
Tongues.Affect["TEST"] = {
["substitute"] = {
[1] = {
["([%a]+)"] = function(a)
return a
end;
["(%A*)$"] = function(a,b)
local rand = math.random(1,2)
if (rand == 1) then
b = "test1"
return b
end;
if (rand == 2) then
b = "test2"
return b
end;
end;
};
};
};
Hope it helps someone out there - as expected, I made it more complicated than it had to be. Simply "jiggling" the symbols is all that was needed.

Ogre::SceneManager::setAmbientLight doese not work

i am building the wiki Advanced Ogre Framework,
then i find that the Ogre::SceneManager::setAmbientLight() does not work at all.
i find nothing useful after google, anyone can give me some idea?
the code is like this:
m_pSceneMgr = OgreFramework::getSingletonPtr()->m_pRoot->createSceneManager(ST_GENERIC, "GameSceneMgr");
m_pSceneMgr->setAmbientLight(Ogre::ColourValue(0.7f, 0.7f, 0.7f));
finally i figure it out bymyslef,
in the framework, i call setAmbientLight() before these code:
DotSceneLoader* pDotSceneLoader = new DotSceneLoader();
pDotSceneLoader->parseDotScene("CubeScene.xml", "General", m_pSceneMgr, m_pSceneMgr->getRootSceneNode());
delete pDotSceneLoader;
there is a node in the CubeScene.xml set the ambient color again, which is (0,0,0), so my call can not work then.

Lua arguments passed to function in table are nil

I'm trying to get a handle on how OOP is done in Lua, and I thought I had a simple way to do it but it isn't working and I'm just not seeing the reason. Here's what I'm trying:
Person = { };
function Person:newPerson(inName)
print(inName);
p = { };
p.myName = inName;
function p:sayHello()
print ("Hello, my name is " .. self.myName);
end
return p;
end
Frank = Person.newPerson("Frank");
Frank:sayHello();
FYI, I'm working with the Corona SDK, although I am assuming that doesn't make a difference (except that's where print() comes from I believe). In any case, the part that's killing me is that inName is nil as reported by print(inName)... therefore, myName is obviously set to nil so calls to sayHello() fail (although they work fine if I hardcode a value for myName, which leads me to think the basic structure I'm trying is sound, but I've got to be missing something simple). It looks, as far as I can tell, like the value of inName is not being set when newPerson() is called, but I can't for the life of me figure out why; I don't see why it's not just like any other function call.
Any help would be appreciated. Thanks!
Remember that this:
function Person:newPerson(inName)
Is equivalent to this:
function Person.newPerson(self, inName)
Therefore, when you do this:
Person.newPerson("Frank");
You are passing one parameter to a function that expects two. You probably don't want newPerson to be created with :.
Try
Frank = Person:newPerson("Frank");

Resources