xgettext: Extract Translatable Messages from R Files in a Package

Description

For each file in the R directory (including system-specific subdirectories) of a package, extract the unique arguments passed to stop, warning, message, gettext and gettextf, or to ngettext.

Usage

xgettext(dir, verbose = FALSE, asCall = TRUE)
xngettext(dir, verbose = FALSE)
xgettext2pot(dir, potFile, name = "R", version, bugs)

Arguments

dir

the directory of a source package.

verbose

logical: should each file be listed as it is processed?

asCall

logical: if TRUE each argument is returned whole, otherwise the strings within each argument are extracted.

potFile

name of po template file to be produced. Defaults to R-pkgname.pot where pkgname is the basename of dir.

name, version, bugs

as recorded in the template file: version defaults the version number of the currently running R, and bugs to "bugs.r-project.org".

Value

For xgettext, a list of objects of class "xgettext" (which has a print method), one per source file that potentially contains translatable strings.

For xngettext, a list of objects of class "xngettext", which are themselves lists of length-2 character strings.

Details

Leading and trailing white space (space, tab and linefeed) is removed for calls to gettext, gettextf, stop, warning, and message, as it is by the internal code that passes strings for translation.

We look to see if these functions were called with domain = NA and if so omit the call if asCall = TRUE: note that the call might contain a call to gettext which would be visible if asCall = FALSE.

xgettext2pot calls xgettext and then xngettext, and writes a PO template file for use with the GNU Gettext tools. This ensures that the strings for simple translation are unique in the file (as GNU Gettext requires), but does not do so for ngettext calls (and the rules are not stated in the Gettext manual, but msgfmt complains if there is duplication between the sets.).

If applied to the base package, this also looks in the .R files in R_HOME/share/R.

Examples

Run this code

# NOT RUN {
## in a source-directory build of R:
xgettext(file.path(R.home(), "src", "library", "splines"))
# }