Updated the developers' manual to reflect the new situation

[pspp-builds.git] / doc / dev / i18n.texi

diff --git a/doc/dev/i18n.texi b/doc/dev/i18n.texi
index 039e32b29f04756ffb989fb94ebb725cbded4f20..3ab86c3d2ec349fb85267ac934bb7c721d9eb304 100644 (file)
--- a/doc/dev/i18n.texi
+++ b/doc/dev/i18n.texi
@@ -11,9 +11,9 @@ in which they are addressed.
 Pspp has three ``working'' locales:
 
 @itemize
-@item The local of the user interface.
-@item The local of the output.
-@item The local of the data. Only the character encoding is relevant.
+@item The locale of the user interface.
+@item The locale of the output.
+@item The locale of the data. Only the character encoding is relevant.
 @end itemize
 
 Each of these locales may, at different times take 
@@ -53,7 +53,6 @@ Any string data stored in a @union{value} will be encoded in the
 dictionary's character set.
 
 
-
 @section System files
 @file{*.sav} files contain a field which is supposed to identify the encoding
 of the data they contain (@pxref{Machine Integer Info Record}).  
@@ -71,7 +70,7 @@ remains unset.
 @section GUI
 The psppire graphic user interface is written using the Gtk+ api, for which 
 all strings must be encoded in UTF8.
-All strings passed to the Gtk+/Glib library functions (except for filenames)
+All strings passed to the GTK+/GLib library functions (except for filenames)
 must be UTF-8 encoded otherwise errors will occur.
 Thus, for the purposes of the programming psppire, the user interface locale 
 should be assumed to be UTF8, even if setlocale and/or nl_langinfo
@@ -81,12 +80,12 @@ indicates otherwise.
 The GLib API has some special functions for dealing with filenames.
 Strings returned from functions like gtk_file_chooser_dialog_get_name are not, 
 in general, encoded in UTF8, but in ``filename'' encoding.
-If that filename is passed to another Glib function which expects a filename, 
+If that filename is passed to another GLib function which expects a filename, 
 no conversion is necessary.
 If it's passed to a function for the purposes of displaying it (eg. in a 
 window's title-bar) it must be converted to UTF8 --- there is a special 
 function for this: g_filename_display_name or g_filename_basename.
-If however, a filename needs to be passed outside of Gtk/Glib (for example to fopen) it must be converted to the local system encoding.
+If however, a filename needs to be passed outside of GTK+/GLib (for example to fopen) it must be converted to the local system encoding.
 
 
 @section Existing locale handling functions
@@ -103,25 +102,20 @@ It is the caller's responsibility to free the returned string when no
 longer required.
 @end deftypefun
 
+In order to minimise the number of conversions required, and to simplify 
+design, PSPP attempts to store all internal strings in UTF8 encoding.
+Thus, when reading system and portable files (or any other data source),
+the following items are immediately converted to UTF8 encoding:
+@itemize
+@item Variable names
+@item Variable labels
+@item Value labels
+@end itemize
+Conversely, when writing system files, these are converted back to the
+encoding of that system file.
 
-For example, in order to display a string variable's value in a label widget in the psppire gui one would use code similar to
-@example
-
-struct variable *var = /* assigned from somewhere */
-struct case c = /* from somewhere else */
-
-const union value *val = case_data (&c, var);
-
-char *utf8string = recode_string (UTF8, dict_get_encoding (dict), val->s,
-      var_get_width (var));
-
-GtkWidget *entry = gtk_entry_new();
-gtk_entry_set_text (entry, utf8string);
-gtk_widget_show (entry);
-
-free (utf8string);
-
-@end example
+String data stored in union values are left in their original encoding.
+These will be converted by the data_in/data_out functions.