Re: guile scheme tutorial

[amirouche]

On 2019-05-07 04:15, rendaw wrote:
> On 5/4/19 8:02 PM, address@hidden wrote:
> > On 2019-05-04 08:08, rendaw wrote:
> > > On 5/3/19 9:45 PM, address@hidden wrote:
> > > > Hello!
> > > (Whoops, replied with the wrong account.)
> > >
> > > Oh, this is great!  I've actually been putting together a small Guix
> > > guide here:
> > > https://gitlab.com/rendaw/blog/blob/master/how_to_guix_for_those_who_dont.md
> > >
> > >
> > > It has a small Guile primer, but it doesn't go into depth or have any
> > > hands on examples like yours.  My goal was to cover just enough so 
> > > that
> > > people could understand Guix configs (or at least 90% of them), so no
> > > recursion, etc.  I'm glad you got into records, I just kind of 
> > > handwaved
> > > that away ("they're functions", not 100% sure this is correct 
> > > either).
> >
> > That is good. The beginning looks like guix is not worthwhile and then
> > you continue in the second page with an introduction to guile and 
> > guix.
> > I find it nice actually.
> >
> > I spotted a minor error:
> >
> >   (system* (string-append #$openssl "/bin/openssl")
> >            "genrsa" "-out" private-key "2048"))
> >
> >  
> > https://gitlab.com/rendaw/blog/blob/master/how_to_guix_for_those_who_dont.md#running-executables
> >
> > Indeed you can run programs like that but in guix it is preferred to 
> > run
> > with invoke, see the source :)
> >
> > Thanks for sharing!
>
> Oh awesome, thanks!  I saw the recommendation to use invoke (in the
> package guide?) but actually I'd like to know what the difference
> between invoke and system* are... the code above was something I 
> grabbed
> from the Guix source somewhere (cups.scm?)
>
> I just checked now (defined in guix/build/utils.scm) and it looks like
> invoke raises an exception if the command has a non-zero exit, but
> otherwise they're the same.

Also it returns #t which is expected in every phase procedure.