D - Suggestion: way to get switch() value
- Russ Lewis (18/18) Mar 27 2002 How about this code:
- Pavel Minayev (16/29) Mar 27 2002 Sorta BASIC? Well, since current object is "this", we could call it
- OddesE (10/40) Mar 27 2002 Cool yes.
- Christophe Bouchon (23/53) Mar 27 2002 And how do you get the value of and outer switch from cases of an inner
- Pavel Minayev (19/78) Mar 27 2002 Yes. If one really need "it" from upper level, he can always catch it:
- Stephen Fuld (9/28) Mar 27 2002 snip
- OddesE (19/37) Mar 27 2002 Do you mean something like this?
- DrWhat? (5/20) Mar 28 2002 switch( temp = foo.bar().baz().fred().wilma().barney() )
- Pavel Minayev (8/11) Mar 28 2002 'cause you have to declare temp outside of switch(), and it will
- DrWhat? (11/26) Mar 28 2002 sorry as I did not know the type foo returns I ommitted specifying the
- Pavel Minayev (9/16) Mar 28 2002 Yes, so what? Another keyword is not a big price for this,
- DrWhat? (13/18) Mar 28 2002 Well so long as I can increase the scope of the variables to that of the...
- Pavel Minayev (8/12) Mar 28 2002 block,
- Russ Lewis (18/18) Mar 28 2002 BOGGLE...here's a weird idea. What if you could declare a named switch,
- Russ Lewis (8/9) Mar 28 2002 I meant "int", not "in":
- Pavel Minayev (4/11) Mar 28 2002 Then, it'd be better to use for-syntax:
- Ben Cohen (7/16) Mar 28 2002 I thought of an idea like this. The next step would be to say that rath...
- Russ Lewis (9/11) Mar 28 2002 Yeah, there's a certain coolness factor to it...but seems like it would ...
- Sean L. Palmer (22/35) Mar 28 2002 The only thing this thread does for me is make me want the old Pascal 'w...
- Pavel Minayev (7/10) Mar 28 2002 Because myVar will now be clattering the namespace, while it's
- Walter (5/8) Apr 23 2002 'with'
- Pavel Minayev (5/7) Apr 23 2002 It is a good idea. I even think it would be better if it worked with
- Walter (4/11) Apr 23 2002 truth,
- Richard Krehbiel (14/27) Mar 28 2002 I hate to be a nay-sayer for interesting ideas... but some things are to...
- Sean L. Palmer (6/10) Mar 28 2002 Yes I like that idea... but most of the time you wouldn't want to decla...
- Richard Krehbiel (14/23) Mar 28 2002 the
How about this code:
switch(foo.bar().baz().fred().wilma().barney())
{
case 0..12:
blah
break;
default:
blah2
break;
}
It would be cool to have a keyword/automatic variable that contains the
value that was put into th switch() clause so that I don't have to call
the long string of functions again (or to have a temporary variable).
--
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.[ (the fox.(quick,brown)) jumped.over(the dog.lazy) ]
.[ (a version.of(English).(precise.more)) is(possible) ]
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Mar 27 2002
"Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message
news:3CA22EAD.6CFF0221 deming-os.org...
How about this code:
switch(foo.bar().baz().fred().wilma().barney())
{
case 0..12:
blah
break;
default:
blah2
break;
}
It would be cool to have a keyword/automatic variable that contains the
value that was put into th switch() clause so that I don't have to call
the long string of functions again (or to have a temporary variable).
Sorta BASIC? Well, since current object is "this", we could call it
"it". =) It would also be nice to have the same feature in with():
with (foo.bar.baz)
{
if (!okay)
kill(it);
}
// -- OR --
switch (foo.bar.baz.okay)
{
case 1:
kill(it);
}
Something I wanted to see in some language for a long time already...
Mar 27 2002
"OddesE" <OddesE_XYZ hotmail.com> "Pavel Minayev" <evilone omen.ru> wrote in message news:a7te3p$2og9$1 digitaldaemon.com..."Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message news:3CA22EAD.6CFF0221 deming-os.org...Cool yes. Better than 'caseval' anyway (see my other reply)... :) -- Stijn OddesE_XYZ hotmail.com http://OddesE.cjb.net _________________________________________________ Remove _XYZ from my address when replying by mailHow about this code: switch(foo.bar().baz().fred().wilma().barney()) { case 0..12: blah break; default: blah2 break; } It would be cool to have a keyword/automatic variable that contains the value that was put into th switch() clause so that I don't have to call the long string of functions again (or to have a temporary variable).Sorta BASIC? Well, since current object is "this", we could call it "it". =) It would also be nice to have the same feature in with(): with (foo.bar.baz) { if (!okay) kill(it); } // -- OR -- switch (foo.bar.baz.okay) { case 1: kill(it); } Something I wanted to see in some language for a long time already...
Mar 27 2002
And how do you get the value of and outer switch from cases of an inner
(nested) switch ? Local(s) variable(s) is(are) back ?
Local declaration (like in for (...) in C++) should be ok:
switch(int it1 = foo.bar().baz().fred().wilma().barney())
{
case 0..12:
switch (int it2 = foo.bar().baz().fred().wilma().casey())
{
case 23..41:
do(it1 + it2);
...
}
// it2 out of scope here
...
}
// it1 out of scope here
By the way, I'd like something like:
var v = expr;
declaration where "= expr" is required and v type is expr static type. This
is not an untyped variable, only an automatic typeof(expr). Sometimes, it
realy bugs me to have to search for the spelling of a type or to have to do
plenty of types copy/paste.
"Pavel Minayev" wrote:
"Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message
news:3CA22EAD.6CFF0221 deming-os.org...
How about this code:
switch(foo.bar().baz().fred().wilma().barney())
{
case 0..12:
blah
break;
default:
blah2
break;
}
It would be cool to have a keyword/automatic variable that contains the
value that was put into th switch() clause so that I don't have to call
the long string of functions again (or to have a temporary variable).
Sorta BASIC? Well, since current object is "this", we could call it
"it". =) It would also be nice to have the same feature in with():
with (foo.bar.baz)
{
if (!okay)
kill(it);
}
// -- OR --
switch (foo.bar.baz.okay)
{
case 1:
kill(it);
}
Something I wanted to see in some language for a long time already...
Mar 27 2002
"Christophe Bouchon" <cbouchon hotmail.com> wrote in message news:a7tlvg$2si8$1 digitaldaemon.com...And how do you get the value of and outer switch from cases of an inner (nested) switch ? Local(s) variable(s) is(are) back ?Yes. If one really need "it" from upper level, he can always catch it: switch (foo) { case 1: that = it; switch (bar) { case 2: that.does(it); } }Local declaration (like in for (...) in C++) should be ok: switch(int it1 = foo.bar().baz().fred().wilma().barney()) { case 0..12: switch (int it2 = foo.bar().baz().fred().wilma().casey()) { case 23..41: do(it1 + it2); ... } // it2 out of scope here ... } // it1 out of scope hereIt would be great; unfortunately, D doesn't support variable declaration in switch() and with() blocks...By the way, I'd like something like: var v = expr; declaration where "= expr" is required and v type is expr static type.Thisis not an untyped variable, only an automatic typeof(expr). Sometimes, it realy bugs me to have to search for the spelling of a type or to have todoplenty of types copy/paste. "Pavel Minayev" wrote:the"Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message news:3CA22EAD.6CFF0221 deming-os.org...How about this code: switch(foo.bar().baz().fred().wilma().barney()) { case 0..12: blah break; default: blah2 break; } It would be cool to have a keyword/automatic variable that containscallvalue that was put into th switch() clause so that I don't have tothe long string of functions again (or to have a temporary variable).Sorta BASIC? Well, since current object is "this", we could call it "it". =) It would also be nice to have the same feature in with(): with (foo.bar.baz) { if (!okay) kill(it); } // -- OR -- switch (foo.bar.baz.okay) { case 1: kill(it); } Something I wanted to see in some language for a long time already...
Mar 27 2002
"Pavel Minayev" <evilone omen.ru> wrote in message news:a7te3p$2og9$1 digitaldaemon.com..."Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message news:3CA22EAD.6CFF0221 deming-os.org...snipHow about this code: switch(foo.bar().baz().fred().wilma().barney()) { case 0..12: blah break; default: blah2 break; } It would be cool to have a keyword/automatic variable that contains the value that was put into th switch() clause so that I don't have to call the long string of functions again (or to have a temporary variable).Sorta BASIC? Well, since current object is "this", we could call it "it". =) It would also be nice to have the same feature in with():Something I wanted to see in some language for a long time already...The first computer language with pronouns! I love it. :-) But if we have trouble keeping the antecedents straight in English, I fear it might be harder in a computer language. :-( -- - Stephen Fuld e-mail address disguised to prevent spam
Mar 27 2002
"Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message
news:3CA22EAD.6CFF0221 deming-os.org...
How about this code:
switch(foo.bar().baz().fred().wilma().barney())
{
case 0..12:
blah
break;
default:
blah2
break;
}
It would be cool to have a keyword/automatic variable that contains the
value that was put into th switch() clause so that I don't have to call
the long string of functions again (or to have a temporary variable).
--
The Villagers are Online! villagersonline.com
.[ (the fox.(quick,brown)) jumped.over(the dog.lazy) ]
.[ (a version.of(English).(precise.more)) is(possible) ]
?[ you want.to(help(develop(it))) ]
Do you mean something like this?
switch(foo.bar().baz().fred().wilma().barney())
{
case 0..12:
Func (caseval);
break;
default:
Func (caseval +2);
break;
}
I like it, kinda like 'this' for objects.
--
Stijn
OddesE_XYZ hotmail.com
http://OddesE.cjb.net
_________________________________________________
Remove _XYZ from my address when replying by mail
Mar 27 2002
Russ Lewis wrote:
How about this code:
switch(foo.bar().baz().fred().wilma().barney())
{
case 0..12:
blah
break;
default:
blah2
break;
}
It would be cool to have a keyword/automatic variable that contains the
value that was put into th switch() clause so that I don't have to call
the long string of functions again (or to have a temporary variable).
switch( temp = foo.bar().baz().fred().wilma().barney() )
{ ... }
Why not?
C 2002/3/28
Mar 28 2002
"DrWhat?" <blackmarlin nospam.asean-mail.com> wrote in message
news:a7v17r$ger$3 digitaldaemon.com...
switch( temp = foo.bar().baz().fred().wilma().barney() )
{ ... }
Why not?
'cause you have to declare temp outside of switch(), and it will
thus interfere with other switch blocks out there. If only
we could declare variables like in for:
switch (int temp = foo.bar.baz)
But even then, why not let the compiler do it, since it's
rather common?
Mar 28 2002
Pavel Minayev wrote:"DrWhat?" <blackmarlin nospam.asean-mail.com> wrote in message news:a7v17r$ger$3 digitaldaemon.com...sorry as I did not know the type foo returns I ommitted specifying the variable define (damn nitt pickers :-)) - what I ment was effectively switch( typeReturnedByFoo temp = foo.bar .... and so onswitch( temp = foo.bar().baz().fred().wilma().barney() ) { ... } Why not?'cause you have to declare temp outside of switch(), and it will thus interfere with other switch blocks out there. If only we could declare variables like in for: switch (int temp = foo.bar.baz)But even then, why not let the compiler do it, since it's rather common?Because that would probably require either another keyword to access. We could use a variable with local scope to the switch block, or auto type define on a = ... the first would require a lot of compiler support and the second can be tricky to implement. So why bother when it is easy to declare a tempory variable, after all in object oriented programming procedures (methods) are normally quite short and having a few extra tempory references should not be an enormous problem.
Mar 28 2002
"DrWhat?" <blackmarlin nospam.asean-mail.com> wrote in message news:a7v78o$k4t$1 digitaldaemon.com...Because that would probably require either another keyword to access.Yes, so what? Another keyword is not a big price for this, I think.We could use a variable with local scope to the switch block, or auto type define on a = ... the first would require a lot of compiler support and the second can be tricky to implement. So why bother when it is easy to declare a tempory variable, after all in object oriented programming procedures (methods) are normally quite short and having a few extra tempory references should not be an enormous problem.You mean declaring temporary outside of switch block? Then why bother declaring counter inside for? I believe that variables should be as local as possible, so, for the value of switch expression, it should be local to switch - whatever way it is done.
Mar 28 2002
Pavel Minayev wrote:You mean declaring temporary outside of switch block? Then why bother declaring counter inside for? I believe that variables should be as local as possible, so, for the value of switch expression, it should be local to switch - whatever way it is done.Well so long as I can increase the scope of the variables to that of the entire procedure I have no problem with allowing variables to be even more local - I really dislike the way VHDL forces you to use locals to for loops which dissappear after the loops exits, stopping you reading the final value. However the D syntax seems to make this senario highly improbable. I would be quite happy with allowing variables to be scoped within a block, so long as we do not end up allowing (as some languages do) ... int x; switch( int x = foo() ) { ... } After all I am not writing the compiler. C 2002/3/28
Mar 28 2002
"DrWhat?" <blackmarlin nospam.asean-mail.com> wrote in message news:a7vnhi$th8$1 digitaldaemon.com...I would be quite happy with allowing variables to be scoped within ablock,so long as we do not end up allowing (as some languages do) ... int x; switch( int x = foo() ) { ... }This is exactly how D works. You can have a variable local to block rather than function, but you cannot have two locals with the same name at once. Now if we get that in-place declaration for switch(), I guess the problem is solved.
Mar 28 2002
BOGGLE...here's a weird idea. What if you could declare a named switch,
kind of like declaring a variable?
int myVar switch(foo.bar().baz().fred().wilma().barney())
{
case 0..12:
DoStuff(myVar); break;
default:
DoOtherStuff(myVar);
}
The scope of the variable would be just the switch block. Or what about
this syntax:
switch(foo.bar().baz().fred().wilma().barney()) as in myVar {...}
Thoughts?
--
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Mar 28 2002
Russ Lewis wrote:
switch(foo.bar().baz().fred().wilma().barney()) as in myVar {...}
I meant "int", not "in":
switch(...) as int myVar {...}
--
The Villagers are Online! villagersonline.com
.[ (the fox.(quick,brown)) jumped.over(the dog.lazy) ]
.[ (a version.of(English).(precise.more)) is(possible) ]
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Mar 28 2002
"Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message
news:3CA335AA.E367FCB4 deming-os.org...
BOGGLE...here's a weird idea. What if you could declare a named switch,
kind of like declaring a variable?
int myVar switch(foo.bar().baz().fred().wilma().barney())
The scope of the variable would be just the switch block. Or what about
this syntax:
switch(foo.bar().baz().fred().wilma().barney()) as in myVar {...}
Thoughts?
Then, it'd be better to use for-syntax:
switch (int myVar = foo.bar().baz()...)
Mar 28 2002
On Thu, 28 Mar 2002 15:24:26 +0000, Russ Lewis wrote:
BOGGLE...here's a weird idea. What if you could declare a named switch,
kind of like declaring a variable?
int myVar switch(foo.bar().baz().fred().wilma().barney()) { case
0..12:
DoStuff(myVar); break;
default:
DoOtherStuff(myVar);
}
I thought of an idea like this. The next step would be to say that rather
than doing "continue/goto case 12" you could simply set myVar to 12 and
"continue". If you wanted to break you could do so as normal.
This gives you a kind of state-machine switch loop. Nice and very
powerful but perhaps a bit dangerous:-)
Ben.
Mar 28 2002
Ben Cohen wrote:This gives you a kind of state-machine switch loop. Nice and very powerful but perhaps a bit dangerous:-)Yeah, there's a certain coolness factor to it...but seems like it would be confusing. Putting a switch inside a while loop would probably be more readable :) -- The Villagers are Online! villagersonline.com .[ (the fox.(quick,brown)) jumped.over(the dog.lazy) ] .[ (a version.of(English).(precise.more)) is(possible) ] ?[ you want.to(help(develop(it))) ]
Mar 28 2002
The only thing this thread does for me is make me want the old Pascal 'with'
statement. Even that had some flaws. I wasn't aware that D had a with
statement. I should go look that up.
I just can't see why you can't merely do this:
int myVar = foo.bar().baz().fred().wilma().barney();
switch (myVar)
{
case 0..12:
DoStuff(myVar); break;
default:
DoOtherStuff(myVar);
}
I don't see what you're gaining in the below. Also, both the syntaxes below
just look wonky to me.
Some way to declare the variable inside the switch expression ala 'for'
loops would be great. Same with 'while' and 'if', although it's hard to
combine a declaration with a comparison to produce the needed boolean.
if (char c = GetChar() < ' ')
TranslateWhiteSpace(c);
Sean
"Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message
news:3CA335AA.E367FCB4 deming-os.org...
BOGGLE...here's a weird idea. What if you could declare a named switch,
kind of like declaring a variable?
int myVar switch(foo.bar().baz().fred().wilma().barney())
{
case 0..12:
DoStuff(myVar); break;
default:
DoOtherStuff(myVar);
}
The scope of the variable would be just the switch block. Or what about
this syntax:
switch(foo.bar().baz().fred().wilma().barney()) as in myVar {...}
Thoughts?
Mar 28 2002
"Sean L. Palmer" <spalmer iname.com> wrote in message news:a7vsn9$1076$1 digitaldaemon.com...I just can't see why you can't merely do this: int myVar = foo.bar().baz().fred().wilma().barney(); switch (myVar)Because myVar will now be clattering the namespace, while it's only needed _inside_ the switch (like in most cases the loop counter is only needed inside the loop). Of course, an additional pair of braces could be added... but it is a hack.
Mar 28 2002
"Sean L. Palmer" <spalmer iname.com> wrote in message news:a7vsn9$1076$1 digitaldaemon.com...The only thing this thread does for me is make me want the old Pascal'with'statement. Even that had some flaws. I wasn't aware that D had a with statement. I should go look that up.I'll save you the trouble <g>. D has a with statement. To tell the truth, I'm not that sure it's a good idea, but it is there.
Apr 23 2002
"Walter" <walter digitalmars.com> wrote in message news:aa336i$274n$1 digitaldaemon.com...I'll save you the trouble <g>. D has a with statement. To tell the truth, I'm not that sure it's a good idea, but it is there.It is a good idea. I even think it would be better if it worked with structures too, especially when filling large WinAPI structs (WNDCLASS, LOGFONT etc).
Apr 23 2002
"Pavel Minayev" <evilone omen.ru> wrote in message news:aa3lsj$2rhv$1 digitaldaemon.com..."Walter" <walter digitalmars.com> wrote in message news:aa336i$274n$1 digitaldaemon.com...truth,I'll save you the trouble <g>. D has a with statement. To tell theThat's a good idea. -WalterI'm not that sure it's a good idea, but it is there.It is a good idea. I even think it would be better if it worked with structures too, especially when filling large WinAPI structs (WNDCLASS, LOGFONT etc).
Apr 23 2002
"Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message
news:3CA22EAD.6CFF0221 deming-os.org...
How about this code:
switch(foo.bar().baz().fred().wilma().barney())
{
case 0..12:
blah
break;
default:
blah2
break;
}
It would be cool to have a keyword/automatic variable that contains the
value that was put into th switch() clause so that I don't have to call
the long string of functions again (or to have a temporary variable).
I hate to be a nay-sayer for interesting ideas... but some things are too
easily done to be worth simplifying further.
I can't think of any problem with saying:
int c = foo.bar().baz().fred().wilma().barney();
switch(c) {
But one other suggestion, that of putting the declaration in the switch, as
in "switch(int c = foo.bar().baz().fred().wilma().barney())", suggests the
notion that a declaration with an initializer is an expression with a value.
That might be worth thinking about.
--
Richard Krehbiel, Arlington, VA, USA
rich kastle.com (work) or krehbiel3 comcast.net (personal)
Mar 28 2002
But one other suggestion, that of putting the declaration in the switch,asin "switch(int c = foo.bar().baz().fred().wilma().barney())", suggests the notion that a declaration with an initializer is an expression with avalue.That might be worth thinking about.Yes I like that idea... but most of the time you wouldn't want to declare variables inside a complex expression. I suppose their scope would usually just be the scope of the statement. Sean
Mar 28 2002
"Sean L. Palmer" <spalmer iname.com> wrote in message news:a7vt2l$10ac$1 digitaldaemon.com...theBut one other suggestion, that of putting the declaration in the switch,asin "switch(int c = foo.bar().baz().fred().wilma().barney())", suggestsI think I'd prefer that it have the same scope as if the declaration came in the immediately preceeding statement. { int a; // ... b not visible here... a = (int b = c * 5); // b visible here, and extends to closing brace. } -- Richard Krehbiel, Arlington, VA, USA rich kastle.com (work) or krehbiel3 comcast.net (personal)notion that a declaration with an initializer is an expression with avalue.That might be worth thinking about.Yes I like that idea... but most of the time you wouldn't want to declare variables inside a complex expression. I suppose their scope would usually just be the scope of the statement.
Mar 28 2002