Optional Variables in MEL

   My biggest problem with MEL Script is that once I’ve written a function and released it I can’t add any new variables to it.  This is an issue when you’re writing rig tools that are used across multiple studios and projects, and then an animator asks for a new addition to the rig.

   So late last year I had this idea.  What if every function I wrote had an extra input variable, a string that could contain any optional flag, which I can use to add extra options to a procedure without breaking existing uses of it?  Inside the function I could specify all my default values, that get replaced if it finds a different value in the string.

   I decided that I’m not likely to ever use tilde (~) so I’m using it to identify flags. (Maya’s own functions use the minus symbol, but it’s also used for negative numeric values, so I wanted something I’d never use)

// Create Cube Function has two input strings: name, and optional flags ;

createCube( “testCube” , “~visible 0 ~scale 2” ) ;

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