World: r3wp
[Core] Discuss core issues
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| Joe 22-May-2006 [4648] | What I've been using in the past is different versions of eval-template for each template and I found the typical bug to be when missing a local given that the templates are evaluated multiple times |
| Anton 22-May-2006 [4649] | After extracting the words you need to convert them all to set-words and put them in a spec block, eg: spec: copy [] foreach word words [append spec to-set-word word] append spec none ; now you can create the context using the spec the-context: context spec ; now unset each word in the context, etc.. |
| Joe 22-May-2006 [4650] | Yes anton, I will code it this way. I am worried that unbinding the words every time is a performance hit |
| Anton 22-May-2006 [4651] | Possibly, we can optimize it later. Binding is supposed to be pretty fast in rebol. |
| Joe 22-May-2006 [4652] | Ladislav, I will try to communicate better. What do you mean by "don't want to have it this way ?" |
| Ladislav 22-May-2006 [4653x2] | eval-template: func [
template
/local res
] [do something with the template...]
|
I just thought, that you wanted to have a function accepting and processing templates | |
| Joe 22-May-2006 [4655] | Yes, my problem is an error handling problem. So far the template blocks are global, and I want to have functions that can build the templates without actually passing the template as a parameter |
| Ladislav 22-May-2006 [4656] | it looks, that you actually don't need UNBIND |
| Gregg 22-May-2006 [4657x2] | Could I ask again for pseudo-code? I'm having the same problem as Ladislav I think. |
If we could step back and look at the problem, without implementation details, it would help me to understand. | |
| Anton 22-May-2006 [4659] | Yes, it's a bit confusing jumping straight into it like this. |
| Gregg 22-May-2006 [4660x2] | I'm only asking because I think you're making this a lot harder than it needs to be, but I can't be sure if I don't understand the problem. |
I've found that I can make things hard for myself, if I fight REBOL, or easy, if I don't. :-) | |
| Anton 22-May-2006 [4662] | Yes, I can't say I find myself needing to do such an operation very often. Been a while since I generated html though. |
| Joe 22-May-2006 [4663x4] | a new attempt. The code that follows works except that I have to define the tags as locals, which is a pain when there are lots of them |
template: to block! "<html><head><title> title </title></head><body>tag1 tag2 tag3</body></html>" blk: remove-each val copy template [tag? val] ?? blk ; == [title tag1 tag2 tag3] eval-template: func [ /local res title tag1 tag2 tag3 ][ res: copy "" bind/copy blk 'res title: "hey" tag1: "this is tag1^/" tag2: "i am tag 2^/" ;tag3: "might not be set^/" repend res bind/copy template 'res res ] probe eval-template | |
so in this example tag3 is none because it was not set in the body but this is clearly an error. I am trying to solve 2 things: | |
1) Not having to declare the locals title tag1 tag2 tag3 in the function spec but have them as locals (might not be possible) | |
| Ladislav 22-May-2006 [4667] | that *is* possible if needed |
| Joe 22-May-2006 [4668x2] | 2) detect when one of the variables has not been set . In the above example with locals defined this can easily be fixed by checking for tags that are none |
Ladislav, then if there is an elegant way to define the locals inside the function body given blk: [title tag1 tag2 tag3] my problem is solved | |
| Gregg 22-May-2006 [4670] | Why not just use FUNCTION with your existing code body and spec; make eval-template funcs on the fly? |
| Anton 22-May-2006 [4671x2] | You would have to define a function every time, yes. |
(for the same reason - contexts can't be extended with new words). | |
| Joe 22-May-2006 [4673] | Yes, but how costly is this ? ( I currently can generate 1000 pages/minute) |
| Gregg 22-May-2006 [4674] | I would still lean towards a higher level solution at some point, but this makes more sense to me than messing with bindings. |
| Ladislav 22-May-2006 [4675] | ;This is one way how to do it: eval-template: lfunc [template [string!]][] [ res: copy "" bind/copy blk 'res title: "hey" tag1: "this is tag1^/" tag2: "i am tag 2^/" ;tag3: "might not be set^/" repend res bind/copy to block! template 'res res ] see http://www.fm.tul.cz/~ladislav/rebol/lfunc.rThis would throw an error if the tag3: line is commented |
| Gregg 22-May-2006 [4676] | Profile it. :-) How many do you *need* to generate, how much data, how many tags, etc. There are a lot of variables here (no pun intended). |
| Joe 22-May-2006 [4677x2] | there are three approaches so far: 1) building function everytime with locals (anton/gregg) 2) template object (anton) and 3) lfunc |
I am going to code this using lfunc for the simplicity it brings and see what I learn Thanks all | |
| Ladislav 22-May-2006 [4679] | the LFUNC approach would cause an error if the 'TAG3 variable were used in the template, otherwise it wouldn't cause an error. Is that what you wanted? |
| Anton 22-May-2006 [4680] | (if your templates are not changing, the corresponding template objects can be made once and reused many times). |
| Joe 22-May-2006 [4681x3] | Ladislav, yes |
Anton, can you code the above example using the template object you proposed | |
Maybe lfunc should be something part of Rebol3 . | |
| Ladislav 22-May-2006 [4684] | :-) |
| Anton 22-May-2006 [4685x3] | ok, hang five. |
Paste this into your console: | |
make-template-context: func [ template /local words spec ][ words: remove-each val to-block template [tag? val] spec: words forall spec [spec/1: to-set-word spec/1] append spec none context spec ] eval-template: func [ template-ctx code /local err ][ unset bind next first template-ctx template-ctx ; unset all words in the context do bind code template-ctx ; do the code ; Check if any tags were not set if find next second template-ctx unset! [ ; were any tags not set ? print "Some tags were not set!" foreach word next first template-ctx [ if not value? in template-ctx word [ print [word "is unset!"] ] ] ] ] ; now test template: "<html><head><title> title </title></head><body>tag1 tag2 tag3</body></html>" template-context: make-template-context template eval-tags: [ title: "web page" tag1: "tag1" tag2: "tag2" tag3: "tag3" ] eval-template template-context eval-tags ; <- this sets all expected tags and is ok eval-template template-context [] ; <- this doesn't set any tags so will complain and show all unset tags | |
| Joe 22-May-2006 [4688] | I am using altme on linux. How do I get the clipboard to work ? |
| Henrik 22-May-2006 [4689] | I think by using the middle mouse button |
| Joe 22-May-2006 [4690x2] | nope, clipboard is broken in linux |
anton, thanks for your example, it's quite useful | |
| Anton 22-May-2006 [4692] | You're welcome. |
| Joe 22-May-2006 [4693x2] | ZZ |
didn't mean to type it | |
| Frank 22-May-2006 [4695] | Clipboard on linux : ctrl-v in altme and middle mouse button in a text editor, it works for me |
| Joe 22-May-2006 [4696] | Frank, yes thanks. For me is ctrl-C + middle mouse |
| Henrik 22-May-2006 [4697] | Why can't I find paths in a loadable block? >> t: [x/y] == [x/y] >> type? first t == path! >> find t 'x/y == none >> find t to-path 'x/y == none |
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