On 7/27/2023 4:31 AM, Mark Waddingham via use-livecode wrote:
On 2023-07-26 18:02, Paul Dupuis via use-livecode wrote:
If I have some text in a field, I can use the "charIndex" property
(see Dictionary) to obtain teh character position of the first
character of a chunk.
Does anyone know of a clever way to do the equivalent of the
charIndex for an arbitrary chunk expression for a container/variable
(i.e. not an actual field object)?
This should work I think:
function charIndexOfWord pWordIndex, pTarget
delete word pWordIndex to -1 of pTarget
return the number of characters in pTarget + 1
end charIndexOfWord
Deletion of chunks works from the first char that makes up the
computed range, so you are left with all the characters which sit
before it.
The index of the character immediately before the start of the
specified word is the just the number of characters which sit before
it; and so the index of the first char of the specified word (which is
what charIndex gives you in a field) is that +1.
The above should work for both +ve and -ve indices, and the obvious
changes will make it work for other string chunks (i.e. change 'Word'
for <chunk>).
Mark,
Thank you very much. This was a brilliant approach and I should have
thought of it myself. However, it is not quite an accurate substitute
for the charIndex property of a field. The following example illustrates
the issue:
pTarget is [The quick brown fox jumps over the lazy dog. The lazy dog
was named "Oz".]
pWordIndex is 8 (having been derived from searching for 'lazy', the 8th
word)
Using [] to quote strings.
delete word 8 to -1 of pTarget -- deletes [lazy] to ["Oz"] but not the
period (.) at the end since it is not considered part of word -1.
This leaves pTarget as [The quick brown fox jumps over the .]
The number of characters in pTarget + 1 is actually not the position of
the [l] in [lazy], which is character 36, but the [a] in [azy],
character 37, due to the period being left.
There are some similar issues, being off by or more, with sentences and
paragraphs in longer text.
Thank you very much for chiming in with a good direction to try.
Paul Dupuis
Researchware
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