Sorry to drudge up old news, but this is an embarrassingly old issue, be nice to have a filter option in the API by now.
Here was my solution because I didn't like the fact that it could possibly overwrite a file accidentally using TIGs approach (untitled != untitled.txt for example). Anyhow it can be a burden to hit save twice, but I'd rather do that 100x then accidentally save over something important.
Where:
EXT = "txt"
default_dir = "c;\\temp\\"
default_file = "untitled"
The following while loop:
name_valid = false
while name_valid == false
path_to_save_to = UI.savepanel("Save Code File", default_dir, default_file)
#path_to_save_to = path_to_save_to.tr("\\","/") # This maybe required.
fileext = File.extname(path_to_save_to) # filename with prefix stripped
filebase = File.basename(path_to_save_to, ".#{EXT}")
#puts fileext.inspect
if fileext == "" || fileext == nil
default_file = filebase + ".#{EXT}"
UI.messagebox "Oops! Including the file extension '#{EXT}'\nThis is an embarrassing workaround...\nPlease hit save again."
#puts default_file.inspect
else
filename = filebase + ".#{EXT}"
path_to_save_to = File.dirname(path_to_save_to) + "\\" + filename
name_valid = true
end
end
