Exception handling is used a lot. Check senders of #on:do:
457 in my Pharo 3.0 That's not counting the 303 #ensure: that are used transparently in things like: aFileRef readStreamDo: [ :s | s upToEnd ] Phil On Mon, Jan 5, 2015 at 2:12 PM, kilon alios <kilon.al...@gmail.com> wrote: > I dont know javascript well nor pharo but I am coming from python and for > this scenario it would make more sense to me to use an exception than an > actual check. At least that is the way Python deals with this situation > which is an approach I really like. > > I know Pharo has exception handling as well, but unlike Python where > exception handling is very popular I have barely seen it used by pharo > coders. I am curious why . > > On Mon, Jan 5, 2015 at 3:01 PM, Sebastian Sastre < > sebast...@flowingconcept.com> wrote: > >> >> On Jan 5, 2015, at 10:38 AM, p...@highoctane.be wrote: >> >> In business apps, the need for default values happen all the time, so the >> idiom has value (not sure for the message name though). >> >> >> Totally. In real apps, having to compare against uninitialized variable >> or nil as response or empty string happens so often that having this method >> makes it quite convenient (AKA lots of code becomes one-liners). >> >> We could use >> >> x := [ self thing ] ifError: [ someDefault ] >> >> >> I understand you’re setting a similar, quite not like it example but in >> any case this one raises and catches an exception and that sounds quite >> less efficient if compared to return self (when object is not nil and is >> not an empty collection/string) >> >> for these purposes. Triggering errors is not too nice still. >> >> Now, what if self itself is nil or empty? >> >> BTW, isEmptyOrNil exists in the image for Collections and >> UndefinedObject. Empty has no meaning for Object, so why test against empty >> in the name? >> >> Note that is not a testing method, it’s a conditional executor of the >> closure. >> The reason why was already mentioned, is to allow you to write this >> one-liner convenience: >> someVar := self thing ifNilOrEmpty: [blah] >> >> `self thing` could be an expensive process that returns something or nil >> or an empty collection. *If* you get nil or empty as result then you >> would get the block values resulting in having blah at someVar >> >> >> In the image, I see that we do have #default: anObject in several places. >> It seems to serve the same intent. >> >> What is the idiom for such things in Pharo? Importing idioms from other >> languages works but if we do have one already, we will introduce confusion. >> >> >> how can you do that one-liner without introducing *ifNilOrEmpty:* ? >> >> >> >> Phil >> >> >> >> On Mon, Jan 5, 2015 at 1:19 PM, Tudor Girba <tu...@tudorgirba.com> wrote: >> >>> This is not about taste. This is about not promoting the use of nil or >>> dependency or the meaning of empty collection. >>> >>> A better way is to look at the upstream logic and modify that one so >>> that it does not need to know about nil or empty. >>> >>> Cheers, >>> Doru >>> >>> >>> >>> On Mon, Jan 5, 2015 at 1:17 PM, Sebastian Sastre < >>> sebast...@flowingconcept.com> wrote: >>> >>>> taste is taste but would you care to illustrate your point with >>>> examples? >>>> I’m curious about it >>>> >>>> >>>> >>>> > On Jan 5, 2015, at 6:12 AM, stepharo <steph...@free.fr> wrote: >>>> > >>>> > You summarise well the kind of code I do not like. >>>> > isNil everywhere and horrible tests. >>>> > >>>> > Stef >>>> > >>>> > >>>> > Le 4/1/15 23:27, Sebastian Sastre a écrit : >>>> >> Hi guys, >>>> >> >>>> >> I’ve started to use this little one: >>>> >> >>>> >> Object>>ifNilOrEmpty: aBlock >>>> >> >>>> >> self ifNil: [ ^ aBlock value ]. >>>> >> >>>> >> (self isCollection and: [ >>>> >> self isEmpty ]) ifTrue: [ ^ aBlock value ]. >>>> >> >>>> >> ^ self. >>>> >> >>>> >> >>>> >> It allows you to do the widely known JavaScript one-liner: >>>> >> >>>> >> var stuff = this.thing || ‘some default value for when this.thing is >>>> undefined, null or an empty string’. >>>> >> >>>> >> but in smalltalk in this way: >>>> >> >>>> >> stuff := self thing ifNilOrEmpty: [ ‘some default value for when >>>> self thing is nil or an empty string’ ] >>>> >> >>>> >> simple thing feels practical and nice :) >>>> >> >>>> >> >>>> >> >>>> > >>>> > >>>> >>>> >>>> >>> >>> >>> -- >>> www.tudorgirba.com >>> >>> "Every thing has its own flow" >>> >> >> >> >> >> >> >
