Developer's Guide :: Resource strings
There is another topic on how to localize the visual interface for your application, but applications can include strings in the source code that may need to be localized.
Extracting resource strings
RPCL uses the standard PHP method to localize string, which is using gettext(). RadPHP includes a wizard that runs gettext software over all .php files on your project and creates the .po file. That .po file includes all the strings found on your source code in this format:
echo _("string to localize");
That is, are enclosed on a _() function, which is a special function that sends the value you set as input to the gettext engine to look for a match for your specific language.
Once you have a .po file for your strings, you need to edit them and create a .mo file, which is a binary version of your translation.
You can use a tool called poEdit: poEdit
Once you save the translated project, a .mo file will be created.
Using the localized version
RadPHP Internationalization wizard creates the folder structure required by gettext() to find and read .mo files.
To switch to a runtime language, you have to do the same you do to change the visual interface language, and it's to set the Language property, that change also affects the gettext() engine to switch the active language and _() functions will search on the .mo file for a match, if none is found, the original input will be shown.