terrible programmers: my god, it's full of chars

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > YOSPOS > terrible programmers: my god, it's full of chars

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leftist heap: Feb 28, 2013; Fun Shoe

p sure java converts ALL string concats to string builder anyway

code:

public class StringTest {

	public String strTest(String a, String b) {
		return a + b;
	}
}

code:

  public java.lang.String strTest(java.lang.String a, java.lang.String b);
     0 new java.lang.StringBuilder [16]
     3  dup
     4  aload_1 [a]
     5  invokestatic java.lang.String.valueOf(java.lang.Object) : java.lang.String [18]
     8  invokespecial java.lang.StringBuilder(java.lang.String) [24]
    11  aload_2 [b]
    12  invokevirtual java.lang.StringBuilder.append(java.lang.String) : java.lang.StringBuilder [27]
    15  invokevirtual java.lang.StringBuilder.toString() : java.lang.String [31]
    18  areturn

you want to use a string builder if you're doing the concatenation in a loop though because otherwise you will get new string builders in every iteration.

# ? Apr 6, 2015 20:28

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# ? May 10, 2024 09:38

oh no blimp issue: Feb 23, 2011

gently caress programming is complicated

# ? Apr 6, 2015 20:32

Subjunctive: Sep 12, 2006; ✨sparkle and shine✨

rrrrrrrrrrrt posted:

p sure java converts ALL string concats to string builder anyway

code:

public class StringTest {

	public String strTest(String a, String b) {
		return a + b;
	}
}

code:

  public java.lang.String strTest(java.lang.String a, java.lang.String b);
     0 new java.lang.StringBuilder [16]
     3  dup
     4  aload_1 [a]
     5  invokestatic java.lang.String.valueOf(java.lang.Object) : java.lang.String [18]
     8  invokespecial java.lang.StringBuilder(java.lang.String) [24]
    11  aload_2 [b]
    12  invokevirtual java.lang.StringBuilder.append(java.lang.String) : java.lang.StringBuilder [27]
    15  invokevirtual java.lang.StringBuilder.toString() : java.lang.String [31]
    18  areturn

you want to use a string builder if you're doing the concatenation in a loop though because otherwise you will get new string builders in every iteration.

yeah, but I bet the JVM knows an awful lot about that pattern and optimizes it aggressively to avoid the SB allocation; don't care quite enough to look into the OpenJDK sources though.

# ? Apr 6, 2015 20:48

DaTroof: Nov 16, 2000; CC LIMERICK CONTEST GRAND CHAMPION
There once was a poster named Troof
Who was getting quite long in the toof

rrrrrrrrrrrt posted:

eclipse is fine but definitely needs some janitoring.

# ? Apr 6, 2015 20:55

rjmccall: Sep 7, 2007; no worries friend; Fun Shoe

i am pretty sure it does, but probably only in a second-tier mode

once upon a time javac did some simple static optimizations and the jit team bitched that it was making their analysis more difficult or actually inhibiting perfect optimization � which to be fair is easy to imagine for some transformations, like merging local variables � and so they changed javac to be blindingly stupid. that string builder transform is actually dictated by the language spec, otherwise they probably wouldn't do it

i don't know if they've revisited that decision, there is plenty of good research into what early optimizations do and do not inhibit later dynamic optimization

# ? Apr 6, 2015 20:58

Forums Terrorist: Dec 8, 2011

fwiw i was joking, i definitely don't do anything of importance with java

# ? Apr 6, 2015 21:07

CPColin: Sep 9, 2003; Big ol' smile.

If you use + with two or more string literals, the compiler will combine them all into a single literal, which is nice. It'll even helpfully inline constants from other classes for you, making your "do I need a clean build" decisions nice and easy!

Edit: I wrote a dumb article about this, last time it came up. It's unpopular!

CPColin fucked around with this message at 21:36 on Apr 6, 2015

# ? Apr 6, 2015 21:34

Valeyard: Mar 30, 2012; Grimey Drawer

Awia posted:

gently caress programming is complicated

# ? Apr 6, 2015 21:36

brap: Aug 23, 2004; Grimey Drawer

.net does this poo poo apparently http://stackoverflow.com/questions/20029868/understanding-of-net-internal-stringbuildercache-class-configuration

# ? Apr 7, 2015 02:45

Valeyard: Mar 30, 2012; Grimey Drawer

a month out from our exams and the lecturer of the functional programming class sent out an email just now saying the exam (worth 80% of the class) will be multiple choice :psyduck:

epic fail

# ? Apr 7, 2015 14:14

oh no blimp issue: Feb 23, 2011

Valeyard posted:

a month out from our exams and the lecturer of the functional programming class sent out an email just now saying the exam (worth 80% of the class) will be multiple choice epic fail

i wish my functional programming exam was multiple choice!

# ? Apr 7, 2015 14:25

Valeyard: Mar 30, 2012; Grimey Drawer

Awia posted:

i wish my functional programming exam was multiple choice!

but with a traditional paper i could write a partially correct solution and get some of the marks

with this, its all or nothing. and its negatively marked so a wrong solution is going to be detrimental compared to actually helpful

# ? Apr 7, 2015 14:27

oh no blimp issue: Feb 23, 2011

Valeyard posted:

but with a traditional paper i could write a partially correct solution and get some of the marks

with this, its all or nothing. and its negatively marked so a wrong solution is going to be detrimental compared to actually helpful

oh well that sucks, negatively marked exams are dumb

my exam is like 75% on python for some reason

# ? Apr 7, 2015 14:29

Valeyard: Mar 30, 2012; Grimey Drawer

Awia posted:

oh well that sucks, negatively marked exams are dumb

my exam is like 75% on python for some reason

when is your last exam and what are the plans after graduation?

# ? Apr 7, 2015 14:39

Shaggar: Apr 26, 2006

Forums Terrorist posted:

fwiw i was joking, i definitely don't do anything of importance with java

oh so you use c#, then.

# ? Apr 7, 2015 14:42

triple sulk: Sep 17, 2014

c# owns

# ? Apr 7, 2015 14:43

suffix: Jul 27, 2013; Wheeee!

Valeyard posted:

a month out from our exams and the lecturer of the functional programming class sent out an email just now saying the exam (worth 80% of the class) will be multiple choice epic fail

score! you'll ace it! :peanut:

# ? Apr 7, 2015 14:47

oh no blimp issue: Feb 23, 2011

Valeyard posted:

when is your last exam and what are the plans after graduation?

dissertation in for the 28th, exams some time early May.
I've got a place on a graduate scheme atm starting in September but ive got other interviews that are looking for a mid May start, so ill see what happens

what about you?

# ? Apr 7, 2015 14:49

Bloody: Mar 3, 2013

triple sulk posted:

c# owns

# ? Apr 7, 2015 15:47

Share Bear: Apr 27, 2004

intellij is fine and faster than eclipse out of the box

the vim input plugin kinda fucks up a often though

eclipse also throws a lot of poo poo at you right out of the box which you probably don't want or need and cannot disable, which i think is the main difference but thats 6 months in on java

# ? Apr 7, 2015 17:03

Forums Terrorist: Dec 8, 2011

Shaggar posted:

oh so you use c#, then.

i wish, i get to struggle through decade old java assignments instead

i don't actually know if the programming faculty even know c# exists

# ? Apr 7, 2015 17:37

triple sulk: Sep 17, 2014

# ? Apr 7, 2015 20:08

Shaggar: Apr 26, 2006

mechanically separate all non-tab users.

# ? Apr 7, 2015 20:10

fart simpson: Jul 2, 2005; DEATH TO AMERICA

i use 1 space indentation

# ? Apr 7, 2015 20:12

DimpledChad: May 14, 2002; Rigging elections since '87.

i write only manually minified javascript

# ? Apr 7, 2015 20:18

prefect: Sep 11, 2001; No one, Woodhouse.
No one.; Dead Man’s Band

fart simpson posted:

i use 1 space indentation

i don't even like two-space; my eyes are old and weak :corsair:

# ? Apr 7, 2015 20:20

jesus WEP: Oct 17, 2004

lol if you gaf about how you janitor ur indentation instead of letting visual studio 2013 do it for you

# ? Apr 7, 2015 20:22

kitten emergency: Jan 13, 2008; get meow this wack-ass crystal prison

Shaggar posted:

mechanically separate all non-tab users.

shaggar was right

# ? Apr 7, 2015 20:25

Valeyard: Mar 30, 2012; Grimey Drawer

Awia posted:

dissertation in for the 28th, exams some time early May.
I've got a place on a graduate scheme atm starting in September but ive got other interviews that are looking for a mid May start, so ill see what happens

what about you?

sounds like a plan, ill race you to the end. dissertation was handed in already, bunch of exams finishing mid May, and then starting on a grad scheme in september

# ? Apr 7, 2015 20:32

fart simpson: Jul 2, 2005; DEATH TO AMERICA

prefect posted:

i don't even like two-space; my eyes are old and weak

actually i use 4 spaces

# ? Apr 7, 2015 20:38

oh no blimp issue: Feb 23, 2011

Valeyard posted:

sounds like a plan, ill race you to the end. dissertation was handed in already, bunch of exams finishing mid May, and then starting on a grad scheme in september

cool! grad scheme interesting?

# ? Apr 7, 2015 20:42