On Thu, Jul 24, 2014 at 10:07 AM, <mike(_at_)saxonica(_dot_)com> wrote:
let $x := unparsed-text-lines(...)
return ($x[1000], $x[10])
Saxon implements $x using a data structure called a MemoClosure where items
from the input are read on-demand, and then remembered. Reading $x[1000]
will cause the first 1000 items to be read and retained in memory; reading
$x[10] finds that the tenth item is already in memory
Maybe not store the 1000 lines, except the last, but just create a
map N --> offset(N) for the Nth line, N < 1000
This way, if we store what was read (or if it already is conveniently
accessible by offset), then we will retrieve it again only on demand.
Reminds me of <xsl:key> and the key() function -- and maybe something
like key() for streamed data could be designed this way -- obviously
requiring two (partial/on-demand) passes.
Just thinking aloud about this.
--
Cheers,
Dimitre Novatchev
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Truly great madness cannot be achieved without significant intelligence.
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To invent, you need a good imagination and a pile of junk
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Never fight an inanimate object
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To avoid situations in which you might make mistakes may be the
biggest mistake of all
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Quality means doing it right when no one is looking.
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You've achieved success in your field when you don't know whether what
you're doing is work or play
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To achieve the impossible dream, try going to sleep.
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Facts do not cease to exist because they are ignored.
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Typing monkeys will write all Shakespeare's works in 200yrs.Will they
write all patents, too? :)
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I finally figured out the only reason to be alive is to enjoy it.
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