Re: [Groff] \[-+] not available? why?

[Werner LEMBERG]

> nroff(1) says
> 
>     If neither the GROFF_TYPESETTER environment variable nor the -T
>     command line option (which overrides the environment variable)
>     specifies a (valid) device, nroff checks the current locale to
>     select a default output device.
> 
> Why is it useful to have nroff ignore a duff -T value and fall back as
> if it was unspecified?

I can't remember...

>     $ echo '\[-+]' | nroff -Tlatin1 | grep .
>     -+
>     $
> 
> latin1(7) here says
> 
>     Oct   Dec   Hex   Char   Description
>     ───────────────────────────────────────────
>     ...
>     261   177   B1     ±     PLUS-MINUS SIGN
> 
> and that seems defined in the device's fonts
> 
>     $ fgrep +- font/devlatin1/R
>     +-      24      0       0261
>     t+-     "
>     $
> 
> so why isn't grotty outputing the single byte for it?

It does.  However, in your nroff line above, you are searching for
\[-+], not \[+-], which is not the same.

>     $ echo '\[-+]' | groff >/dev/null
>     <standard input>:1: warning: can't find special character `-+'
>     $
> 
> The PostScript glyph name is `plusminus'.

Again, this is \[+-], not \[-+].


    Werner