[Cuis-dev] The Cuis-Smalltalk Book Exercise 2.3: Count of methods

[Luciano Notarfrancesco]

I think we removed those messages from String a few years ago. Someone
should fix the exercise…

On Sun, Dec 3, 2023 at 21:17 Ezequiel Birman via Cuis-dev <
cuis-dev at lists.cuis.st> wrote:

> To answer myself, the fact that we can evaluate `'' raisedTo: n` without
> error seems like an unforeseen consequence of `#adaptToCollection:andSend:`
> relying on `#collect` and how the latter works with empty collections.
>
> On Fri, 1 Dec 2023 at 21:56, Ezequiel Birman <ebirman77 at gmail.com> wrote:
>
>> The exercise is:
>>
>>> How many methods are there in the arithmetic method category of the
>>> String class?
>>>
>>
>> There are no messages categorized as arithmetic in String but in
>> CharacterSequence, which String subclassifies. Maybe it was different
>> before; Squeak Strings implement arithmetic messages, exactly those
>> mentioned in the solution to the exercise:
>>
>>> the count of methods in the last right panel is 6: *, +, -, /, // and \\.
>>>
>> But `String allMethodsInCategory: 'arithmetic'` in both Cuis and Squeak
>> evaluates as:
>>
>>>  #(#* #+ #- #/ #// #\\ #raisedTo:)
>>>
>> Seven methods and yes! you can raise the empty string to the power of n
>> for n ∈ Number. WAT! The result is another empty string :) Are we able to
>> do this because of historical reasons? Strings in Squeak can be added E.g
>> `'3' + '4'` is the string '7'.
>>
>> Btw, I'm sharing my annotations
>> <https://hyp.is/k4BuJpCLEe6_Z59nfniWQQ/cuis-smalltalk.github.io/TheCuisBook/A-brief-introduction-to-the-system-Browser.html>
>> via hypothes.is publicly but you'll need to install the Chrome plugin or
>> the unofficial Firefox extension
>> <https://github.com/diegodlh/unofficial-hypothesis-extension> to see
>> them. I've requested to use their proxy so you don't have to, but it might
>> take some time. Once you install any of the plugins you'll be able to read
>> and write comments. The UI looks like this:
>> [image: imagen.png]
>>
>> --
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