[texhax] To not expanding macros, is there anything else besides \string?

[Joseph Wright]

On 05/01/2011 19:07, Paul Isambert wrote:
> Le 05/01/2011 16:40, Philip Taylor (Webmaster, Ret'd) a écrit :
>>
>> Barhorst, Alan wrote:
>>
>>> Hello, I am sorry for the naivety of this question, but here it
>>> goes. I am trying to use \immediate\write on file 14 and 15 for
>>> information that is generated/input in my main LaTeX session.
>>> They are solutions to problems that I want to assemble in an
>>> appendix. The problem is that any macro I pass to the write
>>> command gets immediately expanded, and all I have found in the
>>> literature is that I need to put \string in front of every
>>> macro. What I am hoping is that there is one big wrapper macro
>>> I can place around anything I want to write to a file for later
>>> expansion. If there is such a creature I would appreciate
>>> someone who could point it out to me. There seems to be hints
>>> of this in styles such as inlinedef, but it seems to not work or
>>> I don't understand how it works.
>>
>> Alan, check the e-TeX Reference Manual : there are many new
>> primitives in e-TeX intended to address exactly this sort
>> of problem.
>>
>> http://www.tug.org/texmf-dist/doc/etex/base/etex_ref.html
>
> What Phil alludes to is:
> First, you're running under eTeX, even though you might not know it.
> Second, eTeX has a primitive called \unexpanded, which, as its name
> indicates, returns its argument with no expansion in such contexts as
> writing to an external file. I.e.:
>
> \write15{\unexpanded{<Your material here>}}
>
> will write what you feed it as is.

Even without e-TeX you can avoid expansion here using a toks.

\begingroup
   \toks@{<Your material here}%
   \write15{\the\toks@}%
\endgroup
-- 
Joseph Wright