Re: [Groff] nop request

[Ralph Corderoy]

Hi Werner and Ted,

Werner wrote:
> The .nop is meant as syntactical sugar only.  I believe that code
> like
> 
> .if a \{\
> .  if b \{\
> .    nop Hallo!
> .  \}
> .\}
> 
> is easier to read than
> 
> .if a \{\
> .  if b \{\
> Hallo!
> .  \}
> .\}
> 
> and better to understand than
> 
> .if a \{\
> .  if b \{\
> .    if 1 Hallo!
> .  \}
> .\}

Wow, that's a strange belief to hold :-)  I look at troff input as
plain text interspersed with commands so I want Hallo! to be at the
start of a line so it stands out as plain text and not a command.  Same
with the C preprocessor.

    #if FEATURE_FOO             #if FEATURE_FOO
    #  if DEBUG                 #  if DEBUG
    int debug;                  #    nop int debug;
    #  endif                    #  endif
    #endif                      #endif

> Do you have a better name?

I've thought hard about this and I don't think so.  Perhaps it is hard
to name because its purpose doesn't fit well?  .nop definitely suggests
no-op which would suggest .\"'s behaviour.  There's .then but that's a
bit strange too.

    .if a \{\
    .  if b \{\
    .    then Hallo!
    .  \}
    .\}

Really, no command is mandatory here and it is hard to name something
that doesn't need to exist.

Ted wrote:
> Also, from time to time I use a definition
> 
>   .de nop
>   ..
> 
> as in
> 
>   .blm nop

That's why I though Wener's .nop was needed (when I didn't understand
its purpose), because .\" wouldn't work there.  I could be wrong.

> So, while I can see the point of Werner's proposal, I think it would
> be a very good idea to call it something else. Maybe ".pad"? I don't
> have a clearly good suggestion for the name.

.pad would suggest some form of padding in the output, like .ce or .tl.

> Finally, I think the interpretation as 'equivalent to ".if 1"' is not
> obvious: does it mean you can use
> 
>   .nop \{Some input
>   and some more input
>   .\}

Yes, I believe that works.  The implementation of .nop simple consumes
whitespace before normal parsing resumes at \{.

    % head x.tr
    .nop \{Some input
    and some more input
    .\}
    end
    % ./test-groff -Tascii < x.tr | cat -s
    Some input and some more input end

It gives the same output if the dot before \} is removed too.


Ralph.