Competition - There must be a better way to .....

Seeing the great response to previous competitions, I thought that I'd start one too. As part of a test framework I'm working on, I want to evaluate the test code in a separate context to avoid clashes between the code being tested and the test framework code. I found it wasn't as easy as simply binding the block to a different context. I've come up with a method based on adding new words in the code to be evaluated to the context before binding them. It seems to work (I haven't tested it extensively yet) but it's complicated and uses recursion. I'm sure many of you can come up with simpler and non-recursive solutions? My code: eval-ctx: make object! [ anchor: none eval: function [code-block [block!]] [ result ][ bind code-block 'anchor if error? set/any 'result try code-block [ result: disarm result ] result ] ] evaluate: function [code-block [block!]] [ words-to-add find-words-to-add p w ][ words-to-add: copy [] find-words-to-add: func [code-block [block!]][ parse code-block [ any [ set w block! ( find-words-to-add w ;; recursive call ) | set w set-word! ( if not in eval-ctx to word! w [ insert insert words-to-add reduce w none ] ) | 'set set w lit-word! ( if not in eval-ctx w [ insert insert words-to-add to set-word! w none ] ) | set p path! set w lit-word! ( if 'set = first p [ if not in eval-ctx w [ insert insert words-to-add to set-word! w none ] ] ) | skip ] ] ] find-words-to-add code-block if words-to-add <> [] [ eval-ctx: make eval-ctx words-to-add ] eval-ctx/eval code-block ] A sample:

>> evaluate [test1: "peter"]

>> test1

>> probe eval-ctx

I had the same problem (similar problem) when I created Framework "Laccio". I solved simply creating a variabile in the external container: internal-variable: none ctx1: context [ internal-variable: "A" ] I used this "trick" to create several instances of the same Layout (View Layout). See the following real example: ctx1: context [ myButton: none myLayout: [ myButton: button "Click me" ] ] view layout ctx1/myLayout If you think I'm to the right way, you can donwload my framework from http://laccio.wordpress.com then take a look to the viewer implementation (not the controller). On Nov 24, 2007 5:13 AM, Peter Wood <pwawood-gmail.com> wrote:

> Seeing the great response to previous competitions, I thought that I'd > start one too. > To unsubscribe from the list, just send an email to > lists at rebol.com with unsubscribe as the subject.

Alessandro I think the problem that you've solved is slightly different to mine. I need to add words to the context after it has been created as I don't know what variables will be supplied until the script is running. Regards Peter On Saturday, November 24, 2007, at 10:55 pm, Alessandro Manotti wrote:

Now I don't remember the function, but in Rebol you can dynamically get the variables used in one function. It means you could create a bind at runtime using such variables.. The problem is in this way you cannot make difference between locals and globals. Can you establish a "standard" and, for example, expect that the new dynamic context may contain a default function (e.g.: called (binder) ) to be called to get/set bind variables? This is the way that in languages like java use with "interface" or abstract classes (like a "promise": you simply say that the new context must contain a specific function(s) ). On Nov 25, 2007 1:45 AM, Peter Wood <pwawood-gmail.com> wrote:

> Alessandro > I think the problem that you've solved is slightly different to mine. I > To unsubscribe from the list, just send an email to > lists at rebol.com with unsubscribe as the subject.

HI Alessandro The code that I posted seems to do what I want: it finds new variables in the code to be tested, adds equivalent words to the context and then binds the code to be tested to the context for the test code. I think there must be a better way to do what I want which is why I started the competition. As for the function, you may be thinking of first which when applied on a function gives the argument block; second gives the body of the function.

>> first :append

>> second :append

>> a: make object! [

>> first a