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.\"	Brook Milligan.  All rights reserved.
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.Dd February 23, 2017
.Dt R2PKG 8
.Os
.Sh NAME
.Nm R2pkg
.Nd create a pkgsrc package for an R package
.Sh SYNOPSIS
.Nm
.Op Fl DehqruVv
.Op Fl E Ar editor
.Op Fl R Ar dependency_file
.Op Ar package
.Sh DESCRIPTION
.Nm
takes the name of an R
.Ar package
that should be turned into a
.Xr pkgsrc 7
package in the current directory.
The generated package includes a
.Pa Makefile
and a mostly complete set of files to get the package going.
However,
the files should be reviewed and perhaps adjusted manually after
.Nm
has finished its job.
To help with this, the original versions of files created by
.Nm
are preserved for reference.
.Pp
.Nm
is intended to help the process of creating a package but is not
intended to fly on autopilot.
.Pp
The
.Pa Makefile
contains all of the variables required for an R package, with
information being taken from the package's
.Pa DESCRIPTION
file on CRAN, which is automatically fetched by
.Nm .
Likewise, the
.Pa DESCR
file is populated with information from the same file.
After
.Pa Makefile
and
.Pa DESCR
are completed,
.Nm
fetches the package and computes its checksum via the
.Ic makesum
target.
.Pp
If the user does not supply the
.Ar package
on the command line, then
.Nm
will prompt for it.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl D
Write the package's description into
.Pa DESCRIPTION .
This may be useful for verifying the information obtained from CRAN.
However, this file must be removed as it is not part of a
.Xr pkgsrc 7
package.
.It Fl E Ar editor
Use
.Ar editor
instead of the user's default editor.
.It Fl e
Do not edit Makefile and DESCR.
.It Fl h
Produce a short help message.
.It Fl q
Do not produce status messages along the way.
.It Fl R Ar dependency_file
Process dependency packages recursively using
.Pa dependency_file
to record dependency information.
This option is intended for
internal use only to implement recursion over dependencies.
Instead, the
.Fl r
option should be used to select recursion.
.It Fl r
Process dependency packages recursively.
A
.Pa depends
file is created that lists the dependencies in
.Xr tsort 1
order.
This is likely the best order for testing the resulting
dependency packages.
In particular, a useful strategy for creating
packages recursively is to (i) run
.Nm
with the
.Fl r
option, (ii) fix all the leaf packages, (iii) rerun
.Nm
with the
.Fl r
option, and (iv) continue until all packages are created.
Repeating runs of
.Nm
once the leaf dependencies are moved into the correct categories will
allow the program to capture the correct dependencies in each
.Pa Makefile .
.It Fl u
Update the
.Xr pkgsrc 7
package.
.Nm
must be run in an R package directory, which is assumed to be named as
.Pa R-package .
The name of the package to be updated will be taken from the directory
name and need not be given on the command line.
.It Fl V
Print the version.
.It Fl v
Generate verbose output.
This may be repeated to increase the verbosity.
.El
.Sh ENVIRONMENT
The following environment variables affect the execution of
.Nm :
.Bl -tag -width BLOCKSIZE
.It Ev PKGEDITOR , EDITOR
Editor used for editing
.Pa Makefile
and
.Pa DESCR .
.It Ev CRAN_URL
The URL to the CRAN mirror for downloading the package's DESCRIPTION
file.
By default,
.Pa ftp://cran.r-project.org .
.El
.Sh EXAMPLES
Use the following commands to create a
.Xr pkgsrc 7
package for the R package
.Ar foo :
.Dl cd pkgsrc/math
.Dl mkdir R-foo
.Dl cd R-foo
.Dl R2pkg foo
Remember to test the resulting package and remove any extra files
created by
.Nm .
.Sh SEE ALSO
.Xr pkgsrc 7
.Sh AUTHORS
.Nm
was written by
.An Brook Milligan Aq Mt brook@NetBSD.org .
.Sh BUGS
.Nm
does not create a finished package; instead, it facilitates the task.
However, the resulting files must be reviewed and possibly edited by
hand.
Although dependencies are included in the generated
.Pa Makefile ,
they are not fully analyzed and likely have incorrect category
information.
Packages created recursively for dependencies are placed
in a newly created, nonstandard
.Pa pkgsrc/R
category directory and must be moved to appropriate category
directories within
.Xr pkgsrc 7
and checked for correctness.