[stringtemplate-interest] Fun with ST4

[Collin Fagan]

*Would it be reasonable to ask for some optional delimiter on property
names?*

Oooops... looks like there has been one for a long time now, I retract that
request, sorry.

Collin

On Sun, Jan 16, 2011 at 2:54 PM, Collin Fagan <collin.fagan at gmail.com>wrote:

> ST4 has been working well for me. My most complicated template files worked
> without a hitch, I guess I never used any of the shortcuts that got axed.
> I've been doing some experimenting with the model adapters and here is my
> feedback.
>
> *Task 1: ST + Doclet API*
> Status: Success, but ...
>
> The 'but' involves the fact that the names of the the methods in the Doclet
> API are unadorned like 'classes()' and 'methods()' etc. That left me one
> choice, and I know you aren't going to like it. I had to just lookup the
> method reflectively. While this makes working with the API really easy... it
> could also be used to invoke any method which is bad. :(
>
> *Task 2: ST + XML/XPath*
> Status: Almost a Success
>
> So I thought it would be interesting to try to build a model adapter that
> takes an XPath expression as a "property". The expression is then used to
> get the right data our of the XML document.
>
> main(doc) ::= <<
>      I found the books: <doc./bookstore/book/title; separator=",">
> >>
>
> Given a document like this:
>
> <?xml version="1.0" encoding="ISO-8859-1"?>
>
> <bookstore>
>
>     <book>
>         <title lang="eng">Harry Potter</title>
>         <price>29.99</price>
>     </book>
>
>     <book>
>         <title lang="eng">Learning XML</title>
>         <price>39.95</price>
>     </book>
>
> </bookstore>
>
> I get this output:
>
> t.stg 2:40: invalid character '/'
> I found the books: Harry Potter,Learning XML
>
> I'm guessing that you never anticipated a property 'name' containing
> slashes. The funny thing is it only complains if the property starts with a
> slash.
>
> The template: <doc.bookstore/book/title; separator=","> works with no
> invalid character output.
>
> Other XPath syntax that contains @ or [] breaks ST which is unsurprising
> since none of those are valid charactes for a Java identifier.
>
> In renderers one can pass whatever symbols they like to the format
> argument. I'm guessing this is because they are surrounded by quotes. Would
> it be reasonabale to ask for some optional delimiter on property names?
>
> Something like: <doc."//bookstore/book/title"; separator=",">
>
> or: <doc.{//bookstore/book/title}; separator=","> or something like that.
>
> I hope this doesn't push the idea too far. I'm not really creating
> arbitrary methods or logic.. ok you can add numbers in XPath, but that about
> it. It's not a touring complete language at all.
>
> *Task 3: *JSR 223 Bindings Proof Of Concept.
> Status: Success
>
> So JSR 223 is the scripting API for Java. This is a common framework that
> allows Java objects to be exposed for consumption by JVM scripting
> languages. JRuby, Groovy, JPython all have compatible bindings implemented.
> Some other template engines (boooo, hisss) also provide bindings for JSR
> 223. Since it's so close to the ST API I thought I see what could be done.
>
> While I don't have the Factory lookup stuff all in place the implementation
> of the main interface "ScriptEngine" is pretty straight forward.
>
> This allows me to execute the following code:
>
> STScriptEngine engine = new STScriptEngine();
> engine.put("attributeName", "world");
> System.out.println(engine.eval("Hello <attributeName>"));
>
> Mine is just a wrapper class that just delegates to ST. I'm sure a more
> serious effort would result in code that pokes at the insides of ST.
>
> Anyway ST4 has been great, really great.
>
> Thanks,
>
> Collin
>
>
>
> On Sun, Jan 16, 2011 at 11:00 AM, Terence Parr <parrt at cs.usfca.edu> wrote:
>
>> Hiya. ST3 needs ANTLR3 as does ST4.  ANTLR3 needs ST3 so yes, they are
>> mutually depend.  ANTLR v4 will need ST4 :)
>> Ter
>> On Jan 15, 2011, at 7:05 PM, Collin Fagan wrote:
>>
>> > Hi,
>> >
>> > I noticed that when trying to port some of my old blog entries from ST3
>> to ST4 that ANTLR seems to include a copy of ST3. Is there a circular
>> dependency between ST and ANTLR?
>> >
>> > Collin
>> > _______________________________________________
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>> > stringtemplate-interest at antlr.org
>> > http://www.antlr.org/mailman/listinfo/stringtemplate-interest
>>
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>
>
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