Re: [Pharo-project] Case statement and lazy comparison in Pharo

March 15, 2010

      I would try and reduce the number of branches first. you can use guard
conditions to exit early.

This is not necessarily exact below, but you hopefully get the idea...

(self currentRow == sortedRows last and: [self currentCell isNil])
	ifTrue: [^self navigationKey: event]

self currentRow ifNil: [^self].

self currentCell ifNil:
	[^self setCurrentRowToNext]

self setCurrentCellToNext.

self currentCell ifNil: [^self].

self currentCell performKeyFocus: event inCellBounds:
	(self pvtGetCellBounds: self currentCell)

A different approach entirely is to have an object(s) that represents
the nil state for the row and cell. That way you are not checking
constantly for it being nil, and perhaps you can dispatch some
behaviour to it.

cheers,
Mike

On Mon, Mar 15, 2010 at 9:49 PM, nullPointer <epicfan@gmail.com> wrote:
...
Well, perhaps is a theme worked in another times but... is possible for Pharo
have a basic Case or elseIf statement? I know is easy create you own
structure control, but not is more useful have a "standard" for everybody?
IÂ´m tired of write code like that...
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â (self currentRow == sortedRows last and: [ self
currentCell isNil ]) ifTrue:
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â [
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â self navigationKey: event
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â ]
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â ifFalse:
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â [
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â (self currentRow notNil and: [ self currentCell isNil ]) ifTrue:
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â [
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â self setCurrentRowToNext.
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â ]
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â ifFalse:
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â [
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â (self currentRow notNil and: [ self currentCell notNil ]) ifTrue:
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â [
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â self setCurrentCellToNext.
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â self currentCell notNil ifTrue:
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â [
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â self currentCell performKeyFocus: event inCellBounds: (self
pvtGetCellBounds: self currentCell).
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â ].
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â ].
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â ].
Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â ].
Write code with that format is pathetical :(
Is valid too have a "and" and "or" lazy? Exists a not lazy with #& and #| Â ,
but could exists an #&& and #|| Â . Is more easy...
Â  Â  Â value1 == value2 and:[ <condition> ] and: [<condition>] ......
or
Â  Â  value1 == value2 && <condition> && <condition> ......... ???
Well, perhaps is a stupid question but I miss a more complete way for write
code. If in Smalltalk is possible do easy that and include it in "core" why
not do it?
Is a reasonable desire :)
Regards
--
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Re: [Pharo-project] Case statement and lazy comparison in Pharo

Michael Roberts