The main page of the manual: http://en.wikibooks.org/wiki/OpenSCAD_User_Manual refers to an openscad source file as a script. The word script makes it sound iterative to me. Is there a better way to explain it? "Anonymous scopes are not considered scopes": { angle = 45; } IMO this should be a separate scope, or give an error. -- View this message in context: http://forum.openscad.org/A-A-1-tp11385p11439.html Sent from the OpenSCAD mailing list archive at Nabble.com.

In a functional programming language, a 'constant' is an expression like '42' which always has the same value, in every run of the program. A 'variable' is a named value that can have different values in different runs of the program. Even if you have a top level definition like x = 0; this can still vary, in OpenSCAD, because you can override the value '0' in several ways, eg by invoking openscad with -Dx=1. Like Bananapeel said, OpenSCAD is a functional programming language. There are many others, such as Haskell, Ocaml, F#, ML, Erlang, and so on. The word 'variable' is used in all of these languages to describe what OpenSCAD calls a variable. And there isn't really a good alternative to the word 'variable'. So we need to do what Bananapeel said: fix the documentation and fix the error reporting so that OpenSCAD can be more easily understood by people coming from an imperative programming background. On 4 February 2015 at 08:34, Richard Benjamin <richard@digicalm.com> wrote: > Hmm, I am no expert, but in your example below, 'a' is not varying, it is > constant - it gets calculated once and set up for use. > > It would only be a variable if it varies during the program run, eg if 'b' > changes at certain points in time....but openscad never 'runs' it just puts > the STL together, and 'b' is always the same. > > > On 04/02/2015 13:03, Bananapeel wrote: >> >> Every other language without destructive update operator (c-style assign) >> calls them variables, I don't see why OpenSCAD should be different. >> >> They aren't "constant", because a constant is a value that never changes. >> function square(s) = s*s; >> b = 6; >> a = square(b); >> The variable a's value isn't constant - it changes according to the value >> of >> b. >> >> What's really needed is: >> * Giving an error message when trying to redefine a variable. >> * Clean up other doubtful cases. >> * An explanation for people from procedural programming languages >> (C-style). >> * Push all these changes to release version. >> >> Have a nice day, >> Bananapeel :) >> >> >> >> >> -- >> View this message in context: >> http://forum.openscad.org/A-A-1-tp11385p11436.html >> Sent from the OpenSCAD mailing list archive at Nabble.com. >> >> _______________________________________________ >> OpenSCAD mailing list >> Discuss@lists.openscad.org >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> > > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >