rebol

The IN function in Rebol finds out if a field is in an object: USAGE: IN object word DESCRIPTION: Returns the word or block in the object's context. IN is a native value. ARGUMENTS: object (any-object! block!) word -- (modified if series) (any-word! block! paren!) The claim is it works with objects or blocks. It works okay if I try it with an object: >> in object [foo: 10 bar: 20] 'foo == foo But if I just try it with a raw block, it gives back NONE: >> in [foo: 10 bar: 20] 'foo == none Guess I'd understand if it didn't support blocks (Rebol2 didn't). But what's the case in which it wouldn't

Note This is not a REBOL-specific question. You can answer it in any language. Background The REBOL language supports the creation of domain-specific languages known as "dialects" in REBOL parlance . I've created such a dialect for list comprehensions, which aren't natively supported in REBOL. A good cartesian product algorithm is needed for list comprehensions. The Problem I've used meta-programming to solve this, by dynamically creating and then executing a sequence of nested foreach statements. It works beautifully. However, because it's dynamic, the code is not very readable. REBOL doesn't

Last night I learned about the /redo option for when you return from a function. It lets you return another function, which is then invoked at the calling site and reinvokes the evaluator from the same position >> foo: func [a] [(print a) (return/redo (func [b] [print b + 10]))] >> foo "Hello" 10 Hello 20 Even though foo is a function that only takes one argument, it now acts like a function that took two arguments . Something like that would otherwise require the caller to know you were returning a function, and that caller would have to manually use the do evaluator on it. Thus without

The current in-depth documentation on variable binding targets Rebol 2. Could someone provide a summary of differences between Rebol 2 and 3? BrianH There isn't really a summary somewhere, so let's go over the basics, perhaps a little more informally than Bindology . Let Ladislav write a new version of his treatise for R3 and Red. We'll just go over the basic differences, in order of importance. Object and Function Contexts Here's the big difference. In R2, there were basically two kinds of contexts: Regular object contexts and system/words . Both had static bindings, meaning that once the

What are the differences between the different Rebol 3 branches, especially with the new REN branch? Is it the platforms they'll run on, the feature set, code organization, the C standard compliance? HostileFork This is an answer destined to become outdated, hence set to Community Wiki . This information is as of Sep-2015 . So if updating this answer after some time has passed, please modify the date as well. Binary download of Rebol3 from rebol.com Last build was 5-Mar-2011 and pre-dates the open source release. No GUI support, no HTTPS support, no serial port support, no UDP support, no