Hello Lambdas! Anonymous Functions in GDScript - Godot 4
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- Опубліковано 6 гру 2023
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As a JS dev I love this.
Just realized that I've been using lambda functions without knowing
As JS dev I am sorry for such horrible lambda and calbacks in Godot. It looks like ancient technology if compare to modern JS.
I've noticed this as i'm going through a godot course on udemy. I started with godot 3.1.7 now onto 4.0 because a thing on my game wasn't working, which made it work correctly. I'm glad it is adding Lambda onto godot. I am loving it so far. It is a nice welcome into godot. I just got back into godot to the half a year now after a 3 year break. it's been a fun journey.
Have to say this is an extremely helpful feature and im very glad it was added, saved me tons of headaches and keeping my code clean
I'm really excited for the Godot 4 tutorials coming up next year.
HELLO GORDON!
Lambda? I cannot help to think of Black Mesa.
Hello Mr. Freeman
Unforeseen consequences.
hello gordon
The right function in the wrong code can make all the difference in the world
@@pablopereyra7126 Perfect
This video changes my life! is the feature I didn't know that I needed but solve a lot of my problems on my recently new programing paradigm focused more on functions as behaviors itself than encapsulating them on objects.
Finally i can understand what lambdas are, they seem pretty useful. I may used them in my code some day.
Thanks for explaining these abstract concepts since these are very hard to understand with mere words!
Hey i can clearly understand this than previous video :)
This is a super useful feature; excited to see it in GDScript! People who are complaining about it should realize they don't have to use them if they don't want to 😅
Nice, thanks
i would need to watch this video 10 times but still amazing feature
Syntax could be improved but I'm glad that feature is there!
Nice!
amazing
what are the dynamics of using those functions with `.bind()` and similar? in a looping function for example, how do i connect a signal to a lanbda that takes the iteration number?
Nice. When will interfaces be available in Godot?
In GDScript they are planned in the form of traits, and I believe that implementation work has started on this already, but as with everything in a free software project, it will come out when it's ready: github.com/godotengine/godot-proposals/issues/6416
Can this be used only when connecting signals or as a comparison function for sorting?
Something like this: sort(list, func(a, b): return a.name < b.name)
It can pretty much be used anywhere you can pass a function. So yes, you can use it for filtering, sorting, mapping... (The sorting function in Godot is sort_custom).
Very javascript!
very scheme.
Lots of languages support anonymous functions; Rust, Kotlin, C++, C#.. They're super useful :)
WHOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO LETS GOOOOOOOOOOOOOOO
lambdas are such a godsend
I appreciate the added functionality but to me it looks more convoluted and prone to mistakes than the old way of doing it. Dtill more options for people the better
oh, yes... making a function call to the interpreter evaluator with the function name as a string and arguments as array is simpler than a callback?
@PaulSpades I have no issue with callbacks, happy they are here I have issue with anonymous functions because without reading whole function I don't know what it does spaw_boss() is good name I know what soul happen immediately func() is rubbish because I need to read the rest of a lines to know what happens in this function.
Callbacks are NOT lambda I am pleased that Godot is moving away from strings everywhere. But I am yet to see good practical example of use of lambda function that doesn't make it harder for me to read.
Notice that I am using word ME in my sentences. They work for you then fantastic use them. The old way works for me great I will use that. The way I code my games doesn't in anyway affect you
Dunno if you saw but you can optionally name them. I do often name them these in my code (typically when it's more than 1-2 lines of code). That way it's more like the functions as we knew them in Godot 3, just with a local scope.
@Gdquest that makes more sense missed the part where you can also give them a name
@@FeniksGaming Well, implementing first order functions into the language was a prerequisite for callbacks, adding support for lambdas is just a cherry on top. I get what you're saying, you can have and use one without the other, and lambdas sort of are an acquired taste.
Personally, the less things I get to name, the less bad names I have in the codebase, and I'm good at following the flow of callbacks. But everybody's different, you prefer to explicitly declare the function with a name. And that's fine, I pull out bigger lambdas into separate functions, sometimes. Cheers!
ok im switching
How do I register to the new school site with my mavenseed data? It doesn't accept my current credentials. :(
We will transfer all accounts and courses from Mavenseed (webiste where you have an account) to GDSchool (our new platform) by the end of the year. You don't have to do anything for that.
If you'd like to purchase a Godot 4 course separately, and you have an account on our old platform (Mavenseed), please use the same email to register on school.gdquest.com. We will link your accounts and port your old courses to the new platform at the end of the year.
@@Gdquest Oh so I didn't need to create an account on the new site, but anyway, I used the same email so I should be fine. Merci!
How do you disconnect?
If you need to disconnect at a specific time while your node/object is still alive, with lambda functions, you'd store the function in a variable.
Minimal example:
var my_func = func():
pass
pressed.connect(my_func)
pressed.disconnect(my_func)
Of course, if you need to disconnect the signal elsewhere in your script, and you need to access the function in different scopes, then you'll need to define a method/regular script function.
And more often than not we don´t need to manually disconnect signals as they automatically get cleaned up when deleting the node/object, so lambda functions are especially useful in that common case.
It's me
But you can't reuse lambda functions. They are nameless, counter-intuitive, and .... what for?!
You can name and reuse them. You can use them as locally scoped functions, so, to avoid spreading code too much, as shown in the video. When you make complex applications, code is much easier to read if the signal connection and callbacks are all in one place.
They're "first-class functions"! You can store lambdas in arrays, use them as input to a function and return them from functions. There's a whole world of "functional programming" which uses this, including modern web development, and most popular languages have added these in the last ~10 years if they didn't already have them (they were invented on *paper* in the 1950's :D)
Ngl I understand what you were thinking when you wrote this comment. This was my opinion about lambdas the first time I heard about them. But I can assure you lambdas are the bomb. (at least in other languages because I'm a uber noob in Godot and haven't used them in it yet)
What's actually counterintuitive is the fact that GSCript doesn't support closures yet. It's when you return a function from a function AND the returned function "remembers" the context it had inside the fuction that returned it. It sounds very abstract, and it is, but it's supported in almost all languages that support lambdas.
can you store one in a dictionary?
Yes
@@Gdquest thanks
lambdas are.... not clean code... :/
you sound like a java developer
hahahahaha