The Nineteenth Byte

9:07 PM

so i was checking the meta, to check out how things work now (i wasn't participating on this website for a long time), and i found a certain comment interesting

110

A: Default for Code Golf: Input/Output methods

Functions may output via their return value(s)

"Wait, are there languages that have functions without return values? o.O"

i actually wonder in how many programming languages that's the case, like i know it's the case in Turing-complete Rust macros, but those are part of larger language

AdmBorkBork

PowerShell functions don't have to have return values.

xfix

i mean, it's usually not the case that functions have to return values

moonheart08

@AdmBorkBork so does practically every other language on the planet :P

xfix

for instance in Java, there is void type (not really a type) which means that a function doesn't return a value

moonheart08

Same for C/C++, except void is an actual type and you can have a pointer to it

AdmBorkBork

9:13 PM

I suppose it's depending upon whether it means the function returns foo, or whether the program knows the function executed successfully.

xfix

void * is a type, not sure about void

it's sorta weird

like, in Rust macros, you strictly speaking CAN return tokens, but it's not useful unless you want to finish the computation

AdmBorkBork

I'm sure there are languages that need to have a return value.

Οurous

@AdmBorkBork most functional ones

xfix

but sometimes that return value is () or something as pointless

what is void in Java is an actual type in many functional programming languages

this has its advantages, for instance it interacts better with generics

anyway, about Rust macros, if you want to pass the result to another function, the way to go is to use continuation-passing style

or just specify the function name to return to, but that's not as flexible

Adám

@xfix APL allows proper functions without result.

xfix

9:17 PM

i'm not really interested in languages where functions may not return values

rather i'm currently interested in languages that have functions but they cannot return values in any case

quartata

anything with subroutines rather than proper functions

BASICs

xfix

yeah, that seems like one

quartata

But those then have global states obviously

DJMcMayhem

@Adám Random question. I've seen lots of examples of golfed APL, but I've never seen ungolfed APL before. Do you have a good example of idiomatic readable APL?

quartata

I suppose the purest language of all is one with no side effects and no return values ;)

Adám

9:23 PM

@DJMcMayhem Sure. Why don't you browse the GitHub repos of Dyalog and myself?

@quartata There can be return values, but in the end, nothing is displayed. Yes, that's what I always say: A pure functional language cannot be used for anything.

DJMcMayhem

Cool, thanks!

xfix

9:36 PM

in the end, a practical functional language probably should output more than 1 bit of a result (depending on whether it halts or not)

of course, due to halting problem, determining whether a program halts or not is rather tricky

where rather tricky means in many cases you can detect it, but sometimes a Turing machine just won't be able to do that

Adám

@DJMcMayhem Btw, my weekly lessons teach proper APL rather than golfed (though I occasionally mention a golfing trick). Feel free to join in anytime. We're currently doing OOP, which is very not-golfy.

xfix

(like a an argumentless function in pure programming language constantly calling itself - clearly an infinite loop)

HyperNeutrino

question: if I have a flask server running in a docker container, how do I connect to that server from another computer without using something like ngrok

I tried curl ipinfo.io/ip and then that_ip:5000 but it doesn't connect

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