Mauro <mauro...@runbox.com> wrote: > Maybe you can be a bit more explicit in what you mean, examples would > help too.
Sorry for the fuzziness. This is an example of what I mean: let x = 10 end here, the same expression "x = 10" will either assign a new value to x if such a /global/ exists, or create a new /local/ binding. This is already bad enough[1]. Then, begin/end behaves differently. Then, "if" doesn't introduce a new block, but some others constructs do, and some don't. And then, some like "for" do or don't, it depends. Now even worse: x = 10 function foo() println(x) x = 5 println(x) end will break on the first println (one could expect to get 10, the global value for x) because since there is an assignment /later on/, a new /local/ binding will be created for x (which BTW is the exact opposite of what let does!), but this binding isn't available to the first println. And also, since a variable cannot switch from global to local (or vice-versa) in the same block, the intuition (well, mine anyway ;-)) that after the assignment, the scoping changes, is wrong. And then, as you mention, nested functions will behave yet differently. All of this looks really bad. So IMHO, the real problem is that there are two distinct concepts: assigning a new value to an existing binding, and creating a new binding, possibly with an initial assignment. These are separate things and mixing the two in such ways is wrong, and also quite surprising, knowing the lispy side of this language. Footnotes: [1] consider that a simple typo in your code may lead to silently creating a new variable, which will never be used. -- ELS'16 registration open! http://www.european-lisp-symposium.org Lisp, Jazz, Aïkido: http://www.didierverna.info
