Re: [Groff] read-only number register

[Ingo Schwarze]

Hi,

SGT. Garcia wrote on Mon, Mar 02, 2015 at 07:32:18PM -0500:
> On Mar 03  00:40 +0100, Ingo Schwarze wrote:

>> A roff document can read from the number register (for example
>> using the \n espace sequence) but cannot change the value of
>> the register (for example, assigning to it with the .nr request
>> won't work).

> i guess i'm looking for a glossary.

http://www.gnu.org/software/groff/manual/html_node/Concept-Index.html

is probably as close to a glossary as it gets.

The Heirloom roff manual

  http://n-t-roff.github.io/heirloom/doctools/troff.pdf

is slightly shorter than the groff manual and may consequently be
somewhat easier to skim through to get a first impression of the
most important terms, but it doesn't include a glossary either.

> for example, what's a request?

A request is a command that is built into the the roff language,
somewhat similar to a reserved word in a programming language,
except that it can only occur after a leading dot or apostrophe
at the beginning of an input line.

> how is it different from a macro?

A macro is a user-defined command, analoguous to a user-defined
function in a procedural programming language.

> and why would one want to read the number register.

That depends on which register; reading and manipulating registers
is most often useful when defining your own macros.

Yours,
  Ingo