[squeak-dev] Smalltalk string API

Levente Uzonyi leves at elte.hu
Sat Feb 19 02:24:47 UTC 2011

On Wed, 16 Feb 2011, Nicolas Cellier wrote:

> I started referencing Smalltalk idioms at
> http://en.wikipedia.org/wiki/Comparison_of_programming_languages_(string_functions)
> I could have focused on ANSI but have chosen Squeak/Pharo. Feel free
> to correct me and to complete me.
> This is a very enlighting exercize, especially for pointing when API
> turns to be not that bright.
> During my perigrination, I notably noticed this:
> #compare: returns 1, 2, or 3 : this is both very object oriented, very
> intuitive and very standard and the rest of the world is stupid,
> unless...

1, 2 and 3 was a bad choice, -1, 0 and 1 would have been better, though I 
don't like those either.

> #findLastOccurrenceOfString:startingAt: in its current form is stupid
> to my taste, because
> 1) implementation is inefficient
> 2) the startingAt: only skip the beginning of the string which seems
> odd for a rfind operation
> I would rather expect this kind of usage:
> last := aString findLastOccurrenceOfString: 'to' startingAt: aString size.
> lastButOne := aString findLastOccurrenceOfString: 'to' startingAt: last - 1.


> The CamelCase is sometimes abusive like #includesSubString:

This part of the system is really messy. There are also several methods 
for doing the same (or very similary) things. For example:



or my favorites



> There is no format. I know, purists will tell me that encoding a
> format in a cryptic string is not in the Smalltalk spirit, but please
> then tell me how to specify a formatting efficiently and also remove
> cryptic regex encoding (a pity, it's not in trunk).

Should we create our own fork of VB-Regex or should we resurrect the PCRE 
regex support (it's available on SqueakMap IIRC)?

> I let a few holes (split/join etc...)

I badly needed #join: yesterday. Writing the following multiple times is 
not fun:
String streamContents: [ :stream | foo asStringOn: stream delimiter: bar ]

What Wikipedia contains* as the Squeak/Pharo implementation of join is 

array_of_strings reduce: [:left :right | left , separator , right ])

- it's inefficent (O(n^2) worst case runtime, unnecessary allocations)
- it suggests that _ in a valid character in Smalltalk variable names



> Cheers

More information about the Squeak-dev mailing list