Searching magma string indices

[Brent Pinkney]

Hi Chris,

> Hi Brent!
> 
> I think you've cleverly solved your own question..  By indexing the reversed value, its no different than a keyword index where you can already query on the presence of multiple keywords, as in:
> 
>     myArticles where: [ : each | (each keywords equals: 'Squeak') & (each keywords equals: 'Magma') ]
> 
> So you would just have to convert the wildcards to multiple conjunctions, for example, 'foo%bar' would just have to be translated to:
> 
>     self people where:
>         [ : each |
>         (each familyName startsWith: 'foo')
>         & (each familyName endsWith: 'bar') ]
> 
> and the index would have something like:
> 
>     startsWith: aString
>         self equals: aString
> 
>     endsWith: aString
>         self equals: aString reversed
> 
> You don't even need a separate "reversed" index, just add two entries (the forward and reversed) for each object added to the collection.

Domo arigato gozaimasu Sensei

> Now, the expression '%foo%bar%' goes beyond the first requirement of just searching on a prefix and/or a suffix..  For this a different type of index would be needed that adds every possible value for "Fredfoon Tobart", the following values:
> 
>     fredfoon tobart
>     redfoon tobart
>     edfoon tobart
>     dfoon tobart
>     foon tobart
>     oon tobart
>     on tobart
>     n tobart
>      tobart
>     tobart
>     obart
>     bart
>     art
>     rt
>     t
> 
> Your '%foo%bar%' expression would then need to translate to
> 
>     (familyName from: 'foo' to: 'foo' maAlphabeticalNext)
>     & (familyName from: 'bar' to: 'bar' maAlphabeticalNext)
> 
> to find the object(s) that had "Fredfoon Tobart".

I must admit I am not following you here. Is this one of those Magma keyword indices which I have never managed to grok ?

Also, whilst you are hunting elephants, SQL has both % and ? wildcards: % is any sequence of characters inlcuding the empty string and ? is precicely one character.
So foo??bar would match fooABbar but not fooCDEbar and not fooFbar.

Any chance you could bend Magma's indices into managing expressions with a fixed number of ?s (e.g. ?foo????bar??baz???)

It is to darn hot here to think.



Brent