On Apr 1, 4:23 pm, B Smith-Mannschott <bsmith.o...@gmail.com> wrote: > Thanks very much for the link. I'm enjoying the paper. When I've > addressed my immediate needs (with stringtemplate), I hope to return > to it again in more depth. I have this notion, that an alternate > reader for Clojure in the style of Scribble combined with core > concepts of stringtemplate could make a convenient and yet lispy > templating system for producing non-lisp code and other textual > output.
At the time I worked on this, I've looked at a number of systems, and none were close to being complete in what they were doing. IIRC, I got the general impression that they were all dealing with HTML output, and things started to go downhill when people tried to generalize that. I definitely remember Cheetah being one of these, where there were some really odd corners around indentation -- an issue that came up when people tried to use it as a code generator. OTOH, I made the scribble thing flexible enough that I could even tackle the odd rules of indenting CPP #-lines. You can see an example of that in our ffi code: http://git.racket-lang.org/plt/blob/HEAD:/src/foreign/foreign.c and the source file that generates that: http://git.racket-lang.org/plt/blob/HEAD:/src/foreign/foreign.rktc Look for "(ffi-lib filename no-error?)" in both files, and see how the output gets indented. See also some of that documented in the text languague description at: http://docs.racket-lang.org/scribble/preprocessor.html (but in retrospect I dislike the overloading of lists as markers for an indentation group, and will change that in the very near future to `block'.) I think that I didn't look at StringTemplate at the time -- maybe it wasn't too known then. In any case, looking at some examples (eg, http://www.antlr.org/wiki/display/ST/Five+minute+Introduction), I don't see anything radically different from the other tools in the same category... (The main difference is a little too much buzzword-itis...) So it looks like it's very similar to do these things with plain scribble. For example, if I translate the "homepage.st" example from that page to Racket, I'd do this (the first line specifies using the @-reader, and the `require' line gives me the `output' function which, roughly speaking, displays its argument(s)): #lang at-exp racket (require scribble/text) (define (hello-world title name friends) @list{ <html> <head> <title>@|title|</title> </head> <body> <p>Hello again, @name !</p> <p>Greetings to your friends @(add-between friends ", ")</ p> </body> </html> }) (output (hello-world "Welcome To NotStringTemplate" "World" '("Ter" "Kunle" "Micheal" "Marq"))) Note that the @|...| thing is needed when the racket expression (`title' in the above) needs to be separated from the text around it. The thing that makes this attractive to me is that there is no need to talk about "attributes", "properties", etc -- it's *just* code. If you have some objects then things work fine too, of course, but you can mix things in way you want. For example, I can easily change the above with dropping the `title' argument and instead define a single global value for it -- so the choice of using an argument or a fixed global is something that is up to the code. But there is an important point that they're talking about there -- the model-view separation -- which (I think) is coming from the HTML-generating heritage of these systems, where you want some people to do the HTML design, and other people to do the hacking. (Seems that "logic" is the canonical term for "programming" in these contexts...) Racket has an `include' thing that can basically read some source code file into any context, and the `scribble/text' module uses that and provides an `include/text' which is the same thing, only using the @-reader to read the file. Think about `include' as a kind of a macro that `read's some random file to produce its output, and `include/text' does the same with the extended readtable. So to get this separation, take the textual contents of the `hello-world' function and dump it in a "homepage.st" file (unindented, of course), then change the above code to be: #lang at-exp racket (require scribble/text) (define (hello-world title name friends) (include/text "homepage.st")) (output ...same as above...) You can see a number of similar examples in the templates chapter of our web-server manual, which uses the same thing. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
