This is make-msgfile.c in view mode; [Download] [Up]
/*
PROPOSAL FOR HOW THIS ALL OUGHT TO WORK
this isn't implemented yet, but this is the plan-in-progress
In general, it's accepted that the best way to internationalize is for all
messages to be referred to by a symbolic name (or number) and come out of a
table or tables, which are easy to change.
However, with Emacs, we've got the task of internationalizing a huge body
of existing code, which already contains messages internally.
For the C code we've got two options:
- Use a Sun-like gettext() form, which takes an "english" string which
appears literally in the source, and uses that as a hash key to find
a translated string;
- Rip all of the strings out and put them in a table.
In this case, it's desirable to make as few changes as possible to the C
code, to make it easier to merge the code with the FSF version of emacs
which won't ever have these changes made to it. So we should go with the
former option.
The way it has been done (between 19.8 and 19.9) was to use gettext(), but
*also* to make massive changes to the source code. The goal now is to use
gettext() at run-time and yet not require a textual change to every line
in the C code which contains a string constant. A possible way to do this
is described below.
(gettext() can be implemented in terms of catgets() for non-Sun systems, so
that in itself isn't a problem.)
For the Lisp code, we've got basically the same options: put everything in
a table, or translate things implicitly.
Another kink that lisp code introduces is that there are thousands of third-
party packages, so changing the source for all of those is simply not an
option.
Is it a goal that if some third party package displays a message which is
one we know how to translate, then we translate it? I think this is a
worthy goal. It remains to be seen how well it will work in practice.
So, we should endeavor to minimize the impact on the lisp code. Certain
primitive lisp routines (the stuff in lisp/prim/, and especially in
cmdloop.el and minibuf.el) may need to be changed to know about translation,
but that's an ideologically clean thing to do because those are considered
a part of the emacs substrate.
However, if we find ourselves wanting to make changes to, say, RMAIL, then
something has gone wrong. (Except to do things like remove assumptions
about the order of words within a sentence, or how pluralization works.)
There are two parts to the task of displaying translated strings to the
user: the first is to extract the strings which need to be translated from
the sources; and the second is to make some call which will translate those
strings before they are presented to the user.
The old way was to use the same form to do both, that is, GETTEXT() was both
the tag that we searched for to build a catalog, and was the form which did
the translation. The new plan is to separate these two things more: the
tags that we search for to build the catalog will be stuff that was in there
already, and the translation will get done in some more centralized, lower
level place.
This program (make-msgfile.c) addresses the first part, extracting the
strings.
For the emacs C code, we need to recognise the following patterns:
message ("string" ... )
error ("string")
report_file_error ("string" ... )
signal_simple_error ("string" ... )
signal_simple_error_2 ("string" ... )
build_translated_string ("string")
#### add this and use it instead of build_string() in some places.
yes_or_no_p ("string" ... )
#### add this instead of funcalling Qyes_or_no_p directly.
barf_or_query_if_file_exists #### restructure this
check all callers of Fsignal #### restructure these
signal_error (Qerror ... ) #### change all of these to error()
And we also parse out the `interactive' prompts from DEFUN() forms.
#### When we've got a string which is a candidate for translation, we
should ignore it if it contains only format directives, that is, if
there are no alphabetic characters in it that are not a part of a `%'
directive. (Careful not to translate either "%s%s" or "%s: ".)
For the emacs Lisp code, we need to recognise the following patterns:
(message "string" ... )
(error "string" ... )
(format "string" ... )
(read-from-minibuffer "string" ... )
(read-shell-command "string" ... )
(y-or-n-p "string" ... )
(yes-or-no-p "string" ... )
(read-file-name "string" ... )
(temp-minibuffer-message "string")
(query-replace-read-args "string" ... )
I expect there will be a lot like the above; basically, any function which
is a commonly used wrapper around an eventual call to `message' or
`read-from-minibuffer' needs to be recognised by this program.
(dgettext "domain-name" "string") #### do we still need this?
things that should probably be restructured:
`princ' in cmdloop.el
`insert' in debug.el
face-interactive
help.el, syntax.el all messed up
Menu descriptors: one way to extract the strings in menu labels would be
to teach this program about "^(defvar .*menu\n" forms; that's probably
kind of hard, though, so perhaps a better approach would be to make this
program recognise lines of the form
"string" ... ;###translate
where the magic token ";###translate" on a line means that the string
constant on this line should go into the message catalog. This is analagous
to the magic ";###autoload" comments, and to the magic comments used in the
EPSF structuring conventions.
-----
So this program manages to build up a catalog of strings to be translated.
To address the second part of the problem, of actually looking up the
translations, there are hooks in a small number of low level places in
emacs.
Assume the existence of a C function gettext(str) which returns the
translation of `str' if there is one, otherwise returns `str'.
- message() takes a char* as its argument, and always filters it through
gettext() before displaying it.
- errors are printed by running the lisp function `display-error' which
doesn't call `message' directly (it princ's to streams), so it must be
carefully coded to translate its arguments. This is only a few lines
of code.
- Fread_minibuffer_internal() is the lowest level interface to all minibuf
interactions, so it is responsible for translating the value that will go
into Vminibuf_prompt.
- Fpopup_menu filters the menu titles through gettext().
The above take care of 99% of all messages the user ever sees.
- The lisp function temp-minibuffer-message translates its arg.
- query-replace-read-args is funny; it does
(setq from (read-from-minibuffer (format "%s: " string) ... ))
(setq to (read-from-minibuffer (format "%s %s with: " string from) ... ))
What should we do about this? We could hack query-replace-read-args to
translate its args, but might this be a more general problem? I don't
think we ought to translate all calls to format. We could just change
the calling sequence, since this is odd in that the first %s wants to be
translated but the second doesn't.
Solving the "translating too much" problem:
The concern has been raised that in this situation:
- "Help" is a string for which we know a translation;
- someone visits a file called Help, and someone does something
contrived like (error buffer-file-name)
then we would display the translation of Help, which would not be correct.
We can solve this by adding a bit to Lisp_String objects which identifies
them as having been read as literal constants from a .el or .elc file (as
opposed to having been constructed at run time as it would in the above
case.) To solve this:
- Fmessage() takes a lisp string as its first argument.
If that string is a constant, that is, was read from a source file
as a literal, then it calls message() with it, which translates.
Otherwise, it calls message_no_translate(), which does not translate.
- Ferror() (actually, Fsignal() when condition is Qerror) works similarly.
*/
/* Scan specified C and Lisp files, extracting the following messages:
C files:
GETTEXT (...)
DEFER_GETTEXT (...)
DEFUN interactive prompts
Lisp files:
(gettext ...)
(dgettext "domain-name" ...)
(defer-gettext ...)
(interactive ...)
The arguments given to this program are all the C and Lisp source files
of GNU Emacs. .el and .c files are allowed. There is no support for .elc
files at this time, but they may be specified; the corresponding .el file
will be used. Similarly, .o files can also be specified, and the corresponding
.c file will be used. This helps the makefile pass the correct list of files.
The results, which go to standard output or to a file specified with -a or -o
(-a to append, -o to start from nothing), are quoted strings wrapped in
gettext(...). The results can be passed to xgettext to produce a .po message
file.
*/
#include <stdio.h>
#include <string.h>
#define LINESIZE 256
#define GET_LINE fgets (line, LINESIZE, infile)
#define CHECK_EOL(p) if (*(p) == '\0') (p) = GET_LINE
#define SKIP_BLANKS(p) while ((*p) == ' ' || (*p) == '\t') (p)++
enum filetype { C_FILE, LISP_FILE, INVALID_FILE };
/* some brain-dead headers define this ... */
#undef FALSE
#undef TRUE
enum boolean { FALSE, TRUE };
FILE *infile;
FILE *outfile;
char line[LINESIZE];
void scan_file (char *filename);
void process_C_file (void);
void process_Lisp_file (void);
char *copy_up_to_paren (register char *p);
char *copy_quoted_string (register char *p);
enum boolean no_interactive_prompt (register char *q);
char *skip_blanks (register char *p);
main (int argc, char *argv[])
{
register int i;
outfile = stdout;
/* If first two args are -o FILE, output to FILE. */
i = 1;
if (argc > i + 1 && strcmp (argv[i], "-o") == 0) {
outfile = fopen (argv[++i], "w");
++i;
}
/* ...Or if args are -a FILE, append to FILE. */
if (argc > i + 1 && strcmp (argv[i], "-a") == 0) {
outfile = fopen (argv[++i], "a");
++i;
}
if (!outfile) {
fprintf (stderr, "Unable to open output file %s\n", argv[--i]);
return;
}
for (; i < argc; i++)
scan_file (argv[i]);
return 0;
}
void scan_file (char *filename)
{
enum filetype type = INVALID_FILE;
register char *p = filename + strlen (filename);
if (strcmp (p - 4, ".elc") == 0) {
*--p = '\0'; /* Use .el file instead */
type = LISP_FILE;
} else if (strcmp (p - 3, ".el") == 0)
type = LISP_FILE;
else if (strcmp (p - 2, ".o") == 0) {
*--p = 'c'; /* Use .c file instead */
type = C_FILE;
} else if (strcmp (p - 2, ".c") == 0)
type = C_FILE;
if (type == INVALID_FILE) {
fprintf (stderr, "File %s being ignored\n", filename);
return;
}
infile = fopen (filename, "r");
if (!infile) {
fprintf (stderr, "Unable to open input file %s\n", filename);
return;
}
fprintf (outfile, "/* %s */\n", filename);
if (type == C_FILE)
process_C_file ();
else
process_Lisp_file ();
fputc ('\n', outfile);
fclose (infile);
}
void process_C_file (void)
{
register char *p;
char *gettext, *defun;
while (p = GET_LINE) {
gettext = strstr (p, "GETTEXT");
defun = strstr (p, "DEFUN");
if (gettext || defun) {
if (gettext) {
p = gettext;
p += 7; /* Skip over "GETTEXT" */
}
else if (defun) {
p = defun;
p += 5; /* Skip over "DEFUN" */
}
p = skip_blanks (p);
if (*p++ != '(')
continue;
if (defun) {
register int i;
for (i = 0; i < 5; i++) /* Skip over commas to doc string */
while (*p++ != ',')
CHECK_EOL (p);
if (*p == '\n')
p = GET_LINE;
}
p = skip_blanks (p);
if (*p != '\"') /* Make sure there is a quoted string */
continue;
if (defun && no_interactive_prompt (p))
continue;
fprintf (outfile, "gettext(");
if (gettext)
p = copy_up_to_paren (p);
else
p = copy_quoted_string (p);
fprintf (outfile, ")\n");
}
}
}
void process_Lisp_file (void)
{
register char *p;
char *gettext, *interactive;
enum boolean dgettext = FALSE;
while (p = GET_LINE) {
gettext = strstr (p, "gettext");
interactive = strstr (p, "(interactive");
if (gettext || interactive) {
if (!interactive)
p = gettext;
else if (!gettext)
p = interactive;
else if (gettext < interactive) {
p = gettext;
interactive = NULL;
} else {
p = interactive;
gettext = NULL;
}
if (gettext) {
if (p > line && *(p-1) == 'd')
dgettext = TRUE;
p += 7; /* Skip over "gettext" */
} else
p += 12; /* Skip over "(interactive" */
p = skip_blanks (p);
if (*p != '\"') /* Make sure there is a quoted string */
continue;
if (dgettext) { /* Skip first quoted string (domain name) */
while (*++p != '"')
; /* null statement */
++p;
p = skip_blanks (p);
if (*p != '\"') /* Check for second quoted string (message) */
continue;
}
if (interactive && no_interactive_prompt (p))
continue;
fprintf (outfile, "gettext(");
p = copy_up_to_paren (p);
fprintf (outfile, ")\n");
}
}
}
/* Assuming p points to some character beyond an opening parenthesis, copy
everything to outfile up to but not including the closing parenthesis.
*/
char *copy_up_to_paren (register char *p)
{
for (;;) {
SKIP_BLANKS (p); /* We don't call skip_blanks() in order to */
CHECK_EOL (p); /* preserve blanks at the beginning of the line */
if (*p == ')')
break;
if (*p == '\"')
p = copy_quoted_string (p);
else
fputc (*p++, outfile);
}
return p;
}
/* Assuming p points to a quote character, copy the quoted string to outfile.
*/
char *copy_quoted_string (register char *p)
{
do {
if (*p == '\\')
fputc (*p++, outfile);
fputc (*p++, outfile);
CHECK_EOL (p);
} while (*p != '\"');
fputc (*p++, outfile);
return p;
}
/* Return TRUE if the interactive specification consists only
of code letters and no prompt.
*/
enum boolean no_interactive_prompt (register char *q)
{
while (++q, *q == '*' || *q == '@')
; /* null statement */
if (*q == '\"')
return TRUE;
skip_code_letter:
if (*++q == '\"')
return TRUE;
if (*q == '\\' && *++q == 'n') {
++q;
goto skip_code_letter;
}
return FALSE;
}
char *skip_blanks (register char *p)
{
while (*p == ' ' || *p == '\t' || *p == '\n') {
p++;
CHECK_EOL (p);
}
return p;
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.