Alexander Rabtchevich wrote: > Raphaël, could you please explain me (I'm new to scheme) in a few > words, why the global variables are poor style coding? Global variables can lead to bugs if not used carefully. The use of global variables in Script-Fu is particularly bad since all scripts are read in to a single namespace. A global variable defined in one file can be altered by code in another file without the need to use a Scheme equivalent of a C extern declaration. Everything will seem ok until you add another script file from somewhere that happens to use a global variable with the same name as a global defined in another file. Problems can also arise when two files have global functions with the same name but different behaviour. This sort of problem has been seen even amongst the scripts shipped with GIMP. It is why you now see the use of locally defined functions rather than global ones in most scripts. For an example, look at the alien-glow-arrow.scm file. > But the inability to use global > variables along with scheme syntaxes leads to a good deal of parentheses > which could be a problem to a programmer. When you understand the syntax of the language, the use of local variables instead of global doesn't have any significant impact on the number of parentheses in a script. If someone is afraid of the parentheses they shouldn't be trying to use Scheme. :-) More likely the fear of parentheses is caused by badly formatting the Scheme code (ie. lack of whitespace). Always putting the closing brackets for statements at the end of a single line leads to wasting a lot of time counting brackets. -- Cheers! Kevin. http://www.ve3syb.ca/ |"What are we going to do today, Borg?" Owner of Elecraft K2 #2172 |"Same thing we always do, Pinkutus: | Try to assimilate the world!" #include <disclaimer/favourite> | -Pinkutus & the Borg _______________________________________________ Gimp-developer mailing list Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
