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Book titles

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> > it to learn Lisp.  Basically, for a list of book titles I wanted to 
> > return a list of position in text and the book title, so 
> > (build-book-index "wjhedbwjhbMarkajbdadbGenesis" *books*) 
> 
> > gave: ((21 "Genesis") (10 "Mark")). 
> 
> > I had an approach working but it looked horrid so I thought I would try 
> > loop.  I came up with this: 
> 
> > (defun build-book-index (text books) 
> >  (loop for book in books 
> >     when (search (string-downcase book) (string-downcase text)) collect 
> >     (list it book))) 
> 
> > Of course, ...collect it ... worked but the version above gave: 
> 
> > in: LAMBDA NIL 
> > ;     (LIST IT BOOK) 
> > ; caught WARNING:  undefined variable: IT 
> 
> > Is this expected?   
> 
> Yes. 
> 
> > How can I get round it? 
> 
> Not using IT. 
> 
> (defun build-book-index (text books) 
>   (loop 
>      for book in books 
>      for my-it = (search (string-downcase book) (string-downcase text)) 
>      when my-it collect (list my-it book)))

Factor:

USING: locals ascii sequences.extras ;

:: build-book-index ( books text -- seq )
  text >upper :> utext
  { } books
  [| book |  book >upper utext start [ book 2array suffix ] when* ]
  each
;

{ "Typee" "Mardi" "Pierre" "x" } "pierretypeemardi" build-book-index .

{ { 6 "Typee" } { 11 "Mardi" } { 0 "Pierre" } }

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Book titles "WJ" <w_a_x_man@yahoo.com> - 2013-04-09 04:06 +0000

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