RE: [Groff] Resolving Forward References

[Ted Harding]

On 02-Jan-04 Andrew J. Piziali wrote:
>    As I understand it, groff is a single-pass formatter.  As such, what
> is the recommended way to resolve a forward string or register
> reference?  For example, using the ms macros, I have a footnote:
> 
>     .FS
>     The process of using code coverage is discussed in section
>     \*[useModelSectionNumber], \(lqUse Model.\(rq
>     .FE
> 
> which references a document section number later in the document.  The
> section number is stored in the string register useModelSectionNumber,
> after it is computed by the .NH section header macro.
> 
>    Thank you for your assistance.

Hi Andy,
Single-pass indeed -- but nothing stops you using it twice in a row
under different conditions ...

One way round this problem is to set a "flag" at the beginning of the
file, say

.nr run1 1

and then, at appropriate places, put in a call to a macro which tests
\n[run1] and, if >0, writes out to a file (say xrefs.troff) a line
like

.ds useModelSectionNumber \\*[SN]

where \*[SN] (or \n[SN], depending) is the section number which,
by then, will have been constructed.

At the end of the run, you then have a file full of such definitions
which you can read in on the second pass.

More precisely, you can start your file with

.nr run1 1
.if !\n[run1] .so xrefs.troff
....

and then, for the second pass, change the first line to

.nr run1 0

I hope this helps!

Ted.


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Date: 02-Jan-04                                       Time: 20:47:35
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