ethereum/solidity

The Solidity Contract-Oriented Programming Language - By chatting here you agree to the https://github.com/ethereum/solidity/blob/develop/CODE_OF_CONDUCT.md

Lauri Peltonen

@microbecode

so just check the past transaction logs to see which events have been emitted

GreatYoungShaw

@GreatYoungShaw

oh thank you

Lauri Peltonen

@microbecode

Khuram Shahzad

@KhuramS11116070_twitter

@yubrew

Hello all, I'm wondering if there's a current example (ideally in production) of a dividend token, where eth is split across many token holders?

Christopher

@csplawn918

These all consist of growing pains . Clearly time will heal all Kat errors .

Rahul Soshte

@rahul-soshte

I want to have a token with a infinite supply while decreasing rate of inflation every X number of blocks.How do I do that?

Lauri Peltonen

@microbecode

while decreasing...what?

AKSHAY V G

@akshayvg1133_gitlab

hi what is the necessity of mapping in solidty? i couldnt understand how it works and how one can use mapping

Lauri Peltonen

@microbecode

you don't need to use it. it's just another data structure. it's basically a list which has extra indexes for the first value

Lauri Peltonen

@microbecode

(that is actually a pretty lousy explanation...)

jacekv

@jacekv

@akshayvg1133_gitlab It is like a dictionary or map (depending on language). You have a key which points to a value (key => value).
Example:

map = {
a : 5,
b: 10
}

map[a] => 5
map[b] => 10

Andrew Redden

@androolloyd

This message was deleted

Rahul Soshte

@rahul-soshte

how do I hard fork my token?

Shalu

@shalu0628

hi, new bie here.. Is it possible to retrieve all the array values from a struct in Solidity in Remix itself?

Eric

@efalken

If I have a dynamic array, like "bytes32[] mylist", currently with 4 items, then "mylist.length" equals 4. I saw some code where "mylist.length--" was used to truncate this array by one, so that this would delete the last item in the array, leaving the first 3 items. That makes sense, but I have not seen anything written about it in the documentation, and would like confirmation that this is what is happening (eg, it could be that only the attribute 'length' was affected).

Alex Coventry

@coventry

I'm getting TypeError: Member <methodname> not unique after argument-dependent lookup in contract. There is definitely no explicit collision in the contract or any contracts it inherits from. Can this be caused by a collision in the function selectors? Is there an easy tool which will extract the function selectors for me?

Eric

@efalken

Is it worthwhile to create a separate uint variable for the number of items in an array? For example, I could access the length of a dynamic array via "mylist.length", but also with a variable that incremented when items were added, eg 'numberInList". Is there any memory or other problem created by just accessing "mylist.length"?

Eric

@efalken

Just a Public Service Announcement that mylist.length is much more expensive to call, so if you can afford the extra variable and use it a lot, it will be a lot cheaper. Accessing the length of a 5-dimensional array 10 times costs about 20k gas using the .length method, but only about 0.7k when you assign it to a variable.

Lauri Peltonen

@microbecode

Even if it might be cheaper (you have to calculate also the cost of incrementing the variable etc) it's a big possibility for an error once you forget to increment it or so. It's probably not worth the risk, especially as contracts should always be as simple as possible

AKSHAY V G

@akshayvg1133_gitlab

@jacekv thanks for the help! :-)

jacekv

@jacekv

@efalken Here you have the information about the mylist.length member https://solidity.readthedocs.io/en/v0.5.10/types.html#array-members

@akshayvg1133_gitlab You are welcome :)

Condor

@oijae05wncKMiSv_twitter

Hi there, I am not a developer, content writer, so my question may seem dumb, but still: here are some examples in inline assembly usage https://solidity.readthedocs.io/en/v0.5.3/assembly.html. Can the code from examples be rewritten in plain solidity without assembly? If yes, are there any examples of conversion?

jacekv

@jacekv

@oijae05wncKMiSv_twitter
Sure you can.

mul(1, add(2, 3)) => example: uint a = (2+3) * 1;

Condor

@oijae05wncKMiSv_twitter

Thanks a lot! is there any reference guide to the purpose or whatever)?

jacekv

@jacekv

This might help:
https://medium.com/shyft-network-media/solidity-and-inline-assembly-37871dc582a6

Condor

@oijae05wncKMiSv_twitter

Thanks a lot, I expected no answer in the first place)

jacekv

@jacekv

You are welcome :D

Eric

@efalken

@jacekv Perfect. I wish the Solidity docs had a better search algorithm. Sometime deferring to Google's search is better, in that they actually weight results, while the search box on the Solidity Docs site seems to merely look for keywords regardless of relevance.

Eric

@efalken

@microbecode It's a little scary, but Solidity can't afford the many redundant checks we are used to. So if the only places where dynamic arrays are changed have the counter adjusted accordingly, I do not see how these could become out of sync. For example:

mylist.length--;
mylistlength--;

mylist.push(id);
mylistlength++;

salihu24

@salihu24

Hello guys

Please I have no programming experience, is it possible for me to learn solidity?

Lauri Peltonen

@microbecode

sure it is possible, but it's not the easiest language to start with

salihu24

@salihu24

OK please advise me how do I go about it?

Although I started Java but dropped it

Lauri Peltonen

@microbecode

umh. I'm not sure if there are guides for Solidity with zero coding experience. you should start with some other similar simple language, such as JavaScript which has plenty of beginner guides

salihu24

@salihu24

Like wise python and Java scripts

Lauri Peltonen

@microbecode

well, start with any of those basic languages. any of those will do

learn data structures, loops, variables, all the basics

salihu24

@salihu24

Well to say the fact I have some ideas about these

I even did a nano degree for android development for beginners

But it's been long

About two years back

Schalk Dormehl

@sjalq

@chriseth or any of the other Jedi;
Is there a specific edge case that would cause a transaction to revert when pushing a struct to an array of structs?

        simple memory s = simple({
            a: 1,
            b: 2
        });
        simples.push(s);

Lauri Peltonen

@microbecode

running out of gas?

static array size?

Schalk Dormehl

@sjalq

No static size is specified.

Schalk Dormehl

@sjalq

It also doesn't indicate that this is due to gas. Everwhere i've run it says it reverts.

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