A drag and drop secret

Everybody knowS the old-fashioned way to start program's, like in MS-DOS


This is called a command line. We see here the prompt, the program name, and three textual arguments. The textual arguments are separated by blanks, in Forth fashion. At least on Unix. In MS-DOS one can concatenate the /S to the previous argument. The third argument is special, a so called option. It doesn't tell the what -- which files are to be treated -- but the how. The normal way to write options is with a hyphen, so -s.

The secret of drag and drop is that command lines are not old fashioned at all, but are instrumental to the drag and drop mechanism. For example if you drop the file KNIPPER.BIN on the icon of my Elektor flash program (el-flash), the system in fact executes the following command:

el-flash KNIPPER.BIN

The remainder of the secret is the installing of the icon. It is possible to include fixed options, such that the effect is

el-flash -c2 KNIPPER.BIN

In this case it means that COM2 is where the flash programmer is connected. In order to make real program's, handling command lines gets us half way. The remainder is terribly system-dependant anyway.