On 18 juin 2013, at 11:10, Stéphane Ducasse wrote: > is it not slower?
Yes a bit slower. > and I would remove as much as method as possible from Object. > > why >> | temp | >> temp := <a long expression>. >> temp <aComplexTest> >> ifTrue: [ temp <something> ] >> ifFalse: [ temp <something else> ]. > > is not good enough? If it is the whole content of a method it is good. But in complex methods you end up with a bunch of temps that do are not needed and that decrease readability. > > And finally we should kill as much as possible of these if…. so > > >> Hello everyone. >> >> I see a lot of code that follows the following pattern: >> >> <a long expression> <aComplexTest> >> ifTrue: [ <a long expression> <something> ] >> ifFalse: [ <a long expression> <something else> ]. >> >> The classic refactoring is to store <a long expression> in a temp to avoid >> repetition: >> >> | temp | >> temp := <a long expression>. >> temp <aComplexTest> >> ifTrue: [ temp <something> ] >> ifFalse: [ temp <something else> ]. >> >> Then <a long expression> is evaluated once and the name of the temp can >> carry a meaningful name that helps reading the code. >> But this is more verbose than the first version. >> But if you add the following method in Object: >> >> if: conditionBlock then: trueBlock else: falseBlock >> ^ (conditionBlock cull: self) >> ifTrue: [ trueBlock cull: value ] >> ifFalse: [ falseBlock cull: value ] >> >> You can then rewrite it like that: >> >> <a long expression> >> if: [ :obj | obj <aComplexTest> ] >> then: [ :obj | <something> ] >> else: [ :obj | <something else> ] >> >> The names of the block args can give a meaningful name depending on the >> result of the test (something like ... if: #notEmpty then: [ :collection | >> ... ] else: [ :emptyCollection | ... ]). Using cull: for the three block >> also enable a good flexibility: you can omit the arg when irrelevant. >> >> Likewise, we could also have Object>>#while:do: >> >> while: conditionBlock do: actionBlock >> ^ [ conditionBlock cull: self ] whileTrue: [ actionBlock cull: self ] >> >> What do you think? >> >> Camille >
