This is basicly a copy of the BASIC mid$ function...
mid-string: func [string offset length] [copy/part at string offset length]
--Ryan
"KELLEHER,KEVIN (Non-HP-Roseville,ex1)" wrote:
> Is there a way in Rebol to extract a substring using offsets?
> For example, if I have a string 100 characters long, and
> I want to get characters 25-50, what can I do?
>
> If there is a simple positive answer to that question,
> you can stop here. If not, read the following:
>
> To put this question in context, what I'm trying to do is
> extract a table block out of an html page. What I do is
> this:
> ----------------------------------------------------------------------------
> -----------
> ; --- read the page into a variable
>
> ad: read %index.html
>
> ; --- get the offsets on the open-table tags
>
> htmlTables: make block! 40
> parse ad [any [to "<table" mark: thru ">"
> (append htmlTables index? mark
> append htmlTables "+")]
> ]
>
> ; --- get the offsets for the close-table tags
>
> parse ad [any [to "</table" mark: thru ">"
> (append htmlTables index? mark
> append htmlTables "-")]
> ]
>
> ; --- order them by offset
>
> sort/skip htmlTables 2
>
> ; --- get the seventh open-table tag (it just happens to be the one I want)
>
> openTagCount: 0
> while [openTagCount < 7] [
> openTable: copy/part htmlTables 2
> remove/part htmlTables 2
> if openTable/2 = "+" [ openTagCount: openTagCount + 1 ]
> ]
>
> ; --- get the corresponding close tag (remember that tags can be nested)
>
> openTagCount: 1
> while [openTagCount > 0] [
> closeTable: copy/part htmlTables 2
> remove/part htmlTables 2
> either closeTable/2 = "+"
> [ openTagCount: openTagCount + 1 ]
> [ openTagCount: openTagCount - 1 ]
> ]
>
> ----------------------------------------------------------------------------
> ------------------
>
> Okay, so now I have the offsets; can I do anything with them?
> Do I need to take a different approach?
>
> Kevin Kelleher
>
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