ifTrue ifFalse help

Given:

| binnum index bool|
binnum := 'abc'.
index := 1.
bool:=(binnum at: index).
(bool = 'a')
        ifTrue: [Transcript show: 'ifTrue'; cr]
        ifFalse: [Transcript show: 'ifFalse'; cr].
Transcript show: bool; cr.

Why does this result in:

ifFalse
a

and not

ifTrue
a

I've tried both = and == with no success.

Any help is much appreciated!

try

  bool = $a

to get what you expect. A String consists of Characters (Character is
a separate class).

You could also do

  'abc' inspect

to see what's going on :)

Cheers

Matthias

On Wed, Apr 27, 2011 at 08:05, calcrisk33 <[hidden email]> wrote: _______________________________________________
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bool = $a worked like a charm!  So what exactly does $ do?  I'm more familiar with Java and am trying to break that thought process... relating Squeak to Java.  

Appreciate it!

$a is a way to input the Character "a". Just like you use 'Hello' to
input the string "Hello". In other words, it is a Character literal.

Does that make sense?

Matthias

On Wed, Apr 27, 2011 at 08:35, calcrisk33 <[hidden email]> wrote: _______________________________________________
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Am 2011-04-27 um 08:35 schrieb calcrisk33:

> bool = $a worked like a charm!  So what exactly does $ do?  I'm more familiar
> with Java and am trying to break that thought process... relating Squeak to
> Java.  

Note that Java has not notion of first-class Characters.
Every character is just a string of the length 1 (just like you used it in the first place).

Think of a Smalltalk string as a collection of characters,
then, if you break it apart (with #index: or likewise), you'll
get Characters back.

So Long,
        -Tobias_______________________________________________
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>>>>> "Tobias" == Tobias Pape <[hidden email]> writes:

Tobias> Every character is just a string of the length 1 (just like you
Tobias> used it in the first place).

Not really.

That would imply $a is 'a'.  And it's very much not, which is what the
OP is discovering.

--
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<[hidden email]> <URL:http://www.stonehenge.com/merlyn/>
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calcrisk33 pisze:
> bool = $a worked like a charm!  So what exactly does $ do?  I'm more familiar
> with Java and am trying to break that thought process... relating Squeak to
> Java.  
>
> Appreciate it!
>

Some analogies:

If you know C:
Smalltalk|C
'abc'    |"abc"
$a       |'a'

If you know some philosophy:

compare the relations:
is a kind of
is a part of
or
compare sets in set theoretical and mereological meaning
(in mereological meaning {a}=a)

If you know some linguistics:
compare count nouns with mass nouns

If you know nothing about those:
compare:
half of a car isn't a car
half litre of water is water

is a character a string?
in Smalltalk the answer is NO.


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On Wed, 27 Apr 2011 18:06:29 +0200, Mateusz Grotek

>is a character a string?
>in Smalltalk the answer is NO.

But of course in Smalltalk you can have a string with only one character in
it.  But:

$a is not equal to 'a'
$a is equal to 'a' first or 'a' at: 1.

Having a Character class in Smalltalk is valuable because there are
messages one might want to send to a character that wouldn't make sense
sending to a string, even one of length 1.

Lou
-----------------------------------------------------------
Louis LaBrunda
Keystone Software Corp.
SkypeMe callto://PhotonDemon
mailto:[hidden email] http://www.Keystone-Software.com

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a String in smalltalk: 'hello'
aString in java : "hello"
a Character in smalltalk : $h
a character in java: 'h'

Cheers
Alain

"calcrisk33" <[hidden email]> a écrit dans le message de news:
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Thanks for all the feedback and analogies to Java.  In addition to the original question...

Given:
| a b c |
a := 6 // 2.
b := a asCharacter.
c := b isMemberOf: Character.
Transcript show: 'Member of Char: ', c, '   b = ', b; cr.

Result:
Member of Char: true   b =

I was wondering why b is not getting displayed.

Thanks in advance!



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Hi Rick,

6 // 2 results in an integer value of 3.  3 asCharacter results in a
character with a value of 3 but that is not the printable character of $3
which has an integer value of 51.  Try sending #inspect (like: 3
asCharacter inspect) to objects, it should help you see what/how things are
stored.

Lou

On Thu, 28 Apr 2011 09:26:34 -0400, Richard Wallace
<[hidden email]> wrote:
-----------------------------------------------------------
Louis LaBrunda
Keystone Software Corp.
SkypeMe callto://PhotonDemon
mailto:[hidden email] http://www.Keystone-Software.com

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