On 19 Aug 2018, at 7:56pm, Warren Young <[email protected]> wrote: > On Aug 19, 2018, at 10:03 AM, Norman Dunbar <[email protected]> wrote: > >> Duck Typing? Never heard that before. > > It’s a pretty common term of art in the software development world: > > https://en.wikipedia.org/wiki/Duck_typing
That article was written 20 years too late. Duck Typing was around before everything had methods and properties. An early form of Duck Typing looked like this (pseudocode, not a real language): * Attempt to figure out what kind of value is in A * without risking the program crashing * A is source, B is result, T is temporary and can be lost * LET T = A + 11 * If A is a string, plus appends, and T is now a string ending in "11" * If A is a number, T is a number, but cannot be 2 characters longer * IF LEN(T) = LEN(A) + 2 THEN LET B = "string" ELSE LET B = "number" Because of the limitations of programming languages at the time, you were often limited to passing just one parameter or one variable. But using a string function on a number, or vice versa, would crash the program with an error message. Hence code like that. Simon. _______________________________________________ sqlite-users mailing list [email protected] http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
