an elegant way to return a result

Stef,

So we're finding more and more problems in just a single line of code ;-)

Do you see advantages in this piece of code? Would it be friendlier to the Compiler/VM or a programmer in your opinion?

|nextOrNextAfterNext|

nextOrNextAfterNext := stream next ifNil: [stream next].
^nextOrNextAfterNext

Joachim



Am 02.07.15 um 23:23 schrieb stepharo:

Hi matthieu

on my side:
   
    stream next ifNil: [^stream next].

When you execute a block (far away from the place it was created), it acts as an exception, it stops the execution of currently executed methods and
return to its home context (method that led to the creation of the block) Read deep into Pharo because this is a great chapter.
So people should avoid to put return statement into a block since a block returns already the value of its last expression.

So for me
    arg: [ ^ ... ]

is a big warning.

Stef

Le 1/7/15 23:55, Matthieu Lacaton a écrit :

This whole conversation really makes me want to ask: How do you know if some code is bad, good or completely ugly ? I've not been programming for long but I've already heard sentences like this: "Damn this piece of code is so bad !" so often that I am really wondering. What are the rules ? Performant code makes total sense but it seems there is something else.

Le 1 juil. 2015 23:36, "stepharo" <[hidden email]> a écrit :

I know :D

Le 1/7/15 15:19, [hidden email] a écrit :

Stef,

you're shooting the wrong man! ;-) The crime was committed in your team ;-))))

See you in Brescia

Joachim

Am 30.06.15 um 19:19 schrieb stepharo:

Le 30/6/15 14:39, [hidden email] a écrit :

Ah, Okay, you are mentioning the one and only one case in which this could make sense.... ;-)

Something like

stream next ifNil: [^stream next].

so ugly.
Please we should not teach how to do exception with blocks :)

So there may be cases where the two sends do not return the same result. But that is, of course, not what the OP suggested. Nevertheless, I was too fast in criticizing ;-)

I would consider code like that "less easy" to maintain, however.

Nice thinking Kata ;-)

Joachim



Am 30.06.15 um 14:22 schrieb Esteban Lorenzano:

ah yeah :)

I assumed

first "something aMsg" ~= second "something aMsg”

In case is the same, the correct way is as you say:

^ something aMsg ifNil: [ anotherResult ]

(sorry, he :P)

On 30 Jun 2015, at 13:43, [hidden email] wrote:

Am 30.06.15 um 13:40 schrieb Peter Uhnák:

Make sense if there's code in between.

not sure what you're saying. I mean, sending the message twice makes sense if you already know the outcome? Hmmm...

something aMsg ifNil:[ ^ something aMsg ]. "yay for guards!"
"much more code"
^ aNotherResult

Peter

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Well, thanks for the documentation, the first article was quite interesting and I'm gonna get this book asap :)

When you execute a block (far away from the place it was created), it acts as an exception, it stops the execution of currently executed methods and
return to its home context (method that led to the creation of the block) Read deep into Pharo because this is a great chapter.
So people should avoid to put return statement into a block since a block returns already the value of its last expression.

So for me
    arg: [ ^ ... ]

is a big warning.

Thanks for the explanation, I need to read this chapter, right :p

By the way, I've always used return statements in blocks to "break" out of loops since i didn't find any "break" method in Pharo. Is that bad too ?

2015-07-03 10:11 GMT+02:00 Peter Uhnák <[hidden email]>:

by the way

 

nextOrNextAfterNext := stream next ifNil: [stream next].

I would argue that almost every person who would read this would think it's a bug and it should be ifNotNil:

Also there would be no point in saving it to a variable if you will just return.

^ stream next ifNil: [ stream next ]

By the way, I've always used return statements in blocks to "break" out of loops since i didn't find any "break" method in Pharo. Is that bad too ?

It's still the same thing. Could you provide an example where you do such a thing? When I started with Smalltalk I had also this habit of forcing loops everywhere and breaking them, and only later I realized that it is very often much better expressed as collections with do:/select:/collect:/...

Peter