Re: How to escape the normal interpretation of parent

On Wed, 24 May 2023 at 12:00, Roger L Costello costello@xxxxxxxxx <
xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:

> Hi Folks,
>
> My input consist of lines of text. Here is a sample input:
>
> 1 Record Type
>
> The XSLT program is to transform that line into this XML:
>
> <column>1</column>
> <field-name>Record Type</field-name>
>
> Here is another sample input:
>
> 2 thru 4 Customer/Area Code
>
> The XSLT program is to transform that line into this XML:
>
> <column>2 thru 4</column>
> <field-name>Customer/Area Code</field-name>
>
> I figured that <xsl:analyze-string and regex-group() would be suitable for
> breaking apart each line.
>
> What regex to use for column? The value of column is an integer followed
> optionally by "thru" and another integer. I figured this regex should do
> the job:
>
> ([0-9]+(\s+thru\s+[0-9]+)?)
>
> But, but, but, ....
>
> regex-group(1) means that whole regex. So with this input:
>
> 2 thru 4 Customer/Area Code
>
> regex-group(1) matches:
>
> 2 thru 4
>
> Perfect.
>
> Unfortunately, regex-group(2) matches the inner, optional part. So I end
> up with this:
>
> <column>2 thru 4</column>
> <field-name> thru 4</field-name>
>
> Eek!
>
> Wrong.
>
> How to solve this problem? Is there a way to specify that the inner,
> optional part:
>
> (\s+thru\s+[0-9]+)?
>
> belongs only to regex-group(1), not to regex-group(2)?
>
> Stated another way, is there a way to indicate that the parentheses in the
> inner, optional part are not to be considered as regex-group() syntax?
>
> Stated still another way, is there a way to "escape" the normal
> interpretation of parentheses when utilizing regex-group()?
>

 You could use non capturing group but no real need here, you haven't shown
any regex matching  the second column, something like

^\s*([0-9]+(\s+thru\s+[0-9]+)?)\s*(.*)$

then your columns are groups 1 and 3



> /Roger