OpenEuphoria

Re: Looking for the best "Parse"...

• Posted by Jiri Babor <jbabor at PARADISE.NET.NZ> Oct 25, 2001
• 388 views

Hi, Cassidy,

the function below is probably faster, because it avoids both
recursion and repeated conversions of the same text to lower case. But
you can gain more by simply replacing Rob's elegant, but inefficient
lower() function in wildcard.e by something like this:


constant DIFF = 'a' - 'A'

global function lower(object x)
    integer c
    if atom(x) then
        if x >= 'A' then
            if x <= 'Z' then
                return x + DIFF
            end if
        end if
    else
        for i = 1 to length(x) do
            c = x[i]
            if c >= 'A' then
                if c <= 'Z' then
                    x[i] += DIFF
                end if
            end if
        end for
    end if
    return x
end function

(Note: I did not use 'short-circuit' evaluation, simply because it is
much slower than its equivalent. I hope Rob can fix that soon.)


function parse(sequence text, sequence esc, sequence replace)
    sequence e, r, s
    integer m, n, i, j, p

    e = lower(esc)
    n = length(esc)
    s = lower(text)
    i = 0
    r = {}
    j = match(e, s)
    while j do
        r = (i + j) & r
        i += j + n - 1
        s = s[j+n..length(s)]
        j = match(e, s)
    end while
    m = length(r)
    if m then
        for k = 1 to m  do
            p = r[k]
            text = text[1..p-1] & replace & text[p+n..length(text)]
        end for
    end if
    return text
end function

--jiri

----- Original Message -----
From: "Cassidy Napoli" <gonzotek at yahoo.com>
To: "EUforum" <EUforum at topica.com>
Sent: Friday, 26 October 2001 03:39
Subject: Looking for the best "Parse"...


>
> I want to be able to let the user specify a string of text with
> variables in it that my program will replace.  The goal is to put
the
> current winamp song into a line of text.  I wrote this function,
which
> works, but after reading the "Best Join" discussion, I realized
there
> might be a better way of doing it.  So I am looking for any faster
or
> simpler methods, if there are any.  I'll gladly accept any comments
on
> my coding style, too.  I want to improve it.
>
> [begin code]
> include wildcard.e
>
> global function parseUserText(sequence unParsedText, sequence
escape,
> sequence replace )
> sequence ParsedText
> integer varPos
> varPos = match(lower(escape), lower(unParsedText))
> if not varPos then
>    return unParsedText
> elsif varPos = (length(unParsedText) - length(escape) + 1 ) then
>          ParsedText = unParsedText[1..(length(unParsedText) -
> length(escape))] & replace
>          return parseUserText(ParsedText, escape, replace)
> else
>    if varPos = 1 then
>          ParsedText = replace & unParsedText[(length(escape) +
> 1)..length(unParsedText)]
>          return parseUserText(ParsedText, escape, replace)
>    else
>        ParsedText = unParsedText[1..(varPos - 1)] & replace &
> unParsedText[(varPos + (length(escape)))..length(unParsedText)]
>        return parseUserText(ParsedText, escape, replace)
>    end if
> end if
> end function
> --ex. text = parseUserText("The $A jumped over the lazy
> dog.","$A","quick brown fox")
>
> puts (1, parseUserText("The $A jumped over the lazy
dog.","$A","quick
> brown fox"))
> [end code]
>
>
>