R devel - Aug 2019 - Appetite for eliminating dependency on Perl

Preamble: I am in no way opposed to Perl in general - I love Perl and
probably always will.

R currently has Perl as both a build-time and run-time dependency.  This
adds about 200 Mb, give or take, to the required environment size (as
measured in CentOS - looks like it might be a bit smaller in Ubuntu?).

Not such a huge deal, really, but the actual benefit R gets from the
dependency is quite small.  From my poking around in the R sources (using
`git grep -P '\bperl\b(?! ?= ?(?:TRUE|FALSE))' ` as a filter), it looks
like it's only used in the following nooks & crannies:

* tools/help2man.pl
* tools/install-info.pl
* configure:      INSTALL_INFO="perl
\$(top_srcdir)/tools/install-info.pl"
* m4/R.m4:      INSTALL_INFO="perl
\$(top_srcdir)/tools/install-info.pl"

Ultimately that's only two scripts.  `help2man.pl` seems like it's part
of
the build process, but not used at runtime.  `install-info.pl` seems like
maybe it's runnable at runtime, but requires user initiation to run, at
which point the user is expected to have perl installed.  Either one of
them could probably be ported to another language pretty easily, maybe even
R.

Anything else I missed?

If someone were to volunteer the porting work, would there be any appetite
for eliminating the dependency?

  -Ken

	[[alternative HTML version deleted]]

Dunno about runtime. We used to have much more - all the Rdconv stuff used to be
based on pattern matching by Perl scripts, but they were converted to R scripts
and later to use proper parsers.

For building, if you ever need to regenerate a configure script or write your
own for a package, notice that aclocal & friends are Perl scripts.

-pd
> On 9 Aug 2019, at 00:37 , Ken Williams <kenahoo at gmail.com> wrote:
> 
> Preamble: I am in no way opposed to Perl in general - I love Perl and
> probably always will.
> 
> R currently has Perl as both a build-time and run-time dependency.  This
> adds about 200 Mb, give or take, to the required environment size (as
> measured in CentOS - looks like it might be a bit smaller in Ubuntu?).
> 
> Not such a huge deal, really, but the actual benefit R gets from the
> dependency is quite small.  From my poking around in the R sources (using
> `git grep -P '\bperl\b(?! ?= ?(?:TRUE|FALSE))' ` as a filter), it
looks
> like it's only used in the following nooks & crannies:
> 
> * tools/help2man.pl
> * tools/install-info.pl
> * configure:      INSTALL_INFO="perl
\$(top_srcdir)/tools/install-info.pl"
> * m4/R.m4:      INSTALL_INFO="perl
\$(top_srcdir)/tools/install-info.pl"
> 
> Ultimately that's only two scripts.  `help2man.pl` seems like it's
part of
> the build process, but not used at runtime.  `install-info.pl` seems like
> maybe it's runnable at runtime, but requires user initiation to run, at
> which point the user is expected to have perl installed.  Either one of
> them could probably be ported to another language pretty easily, maybe even
> R.
> 
> Anything else I missed?
> 
> If someone were to volunteer the porting work, would there be any appetite
> for eliminating the dependency?
> 
>  -Ken
> 
> 	[[alternative HTML version deleted]]
> 
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-- 
Peter Dalgaard, Professor,
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Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com