Re: Any plans for a 100% wm syntax compatibility?

Jonathan Revusky-3 wrote:
> 
> For example, forward referencing and reassignment of macros. Consider 
> forward referencing.... this example works:
> 
> #macro (foo) Hello, World #end
> 
> #foreach ($i in [1..5])
>     #foo
> 
> #end
> 
> produces:
> 
>      Hello, World
>      Hello, World
>      Hello, World
>      Hello, World
>      Hello, World
> 
> But suppose we put the macro definition at the end of the file instead 
> of the start. This is the case that Velocity cannot handle and will just 
> output a literal #foo. In this Velocity-bridged FM, it produces:
> 
>      Hello, World ()
>      Hello, World ()
>      Hello, World ()
>      Hello, World ()
>      Hello, World ()
> 
> IOW, in the first case, the Velocity parser parsed () as part of the 
> macro invocation but in the second case, when we forward reference, the 
> () is treated as plain text.
> 
> Of course, this means that it doesn't work with macros that take 
> arguments. Now, this works correctly:
> 
> #macro (foo $bar) Hello, $bar #end
> 
> #foreach ($i in [1..5])
>     #foo("World")
> 
> #end
> 
> but when you put the macro definition at the end, you get:
> 
> Parameter bar unspecified.
> ----------
> ==> macro foo [on line 6, column 1 in duck.vm]
>   in user-directive foo [on line 3, column 4 in duck.vm]
> ----------
> 
> Java backtrace for programmers:
> ----------
> freemarker.template.TemplateException: Parameter bar unspecified.
>          at 
> freemarker.core.ast.ParameterList.getParameterMap(ParameterList.java:186)
> 
> etcetera.
> 
> IOW, it was parsed as #foo followed by the plain text ("World")
> 
> Same sort of problems occur with aliasing a macro.
> 
> #macro (foo $bar) Hello, $bar #end
> #set ($alias = $foo)
> 
> #foreach ($i in [1..5])
>     #alias("World")
> 
> #end
> 
> 
> Parameter bar unspecified.
> 
> etcetera.
> 
> Well... this is all such junk... 
> 
Yes, it is junk, but in our case, the users (non-programmers) don't write
macros, and only use a few
predefined ones in thier "more text"-oriented templates.


Jonathan Revusky-3 wrote:
> 
> I googled a bit for some discussion of 
> this and quickly found:
> 
> http://wiki.apache.org/jakarta-velocity/MacroIssues
> 
> The whole thing is just completely FUBAR'ed. What's interesting about 
> this is that these guys maintain pages like the above one, but then 
> don't ever draw the obvious conclusion, which is that if they really 
> want to have a product of some kind of decent quality, they need to 
> rewrite the parser.
> 
I think, in order to draw conclusions, one needs to understand the thing,
but since
the original authors are all gone, ... :).


Jonathan Revusky-3 wrote:
> 
> But.... even if this bridged thing is better than Velocity, it is so 
> inferior to using FreeMarker itself, it's not funny. No namespaces, no 
> local variables, no macros with blocks, no visit/recurse machinery for 
> processing XML, no built-ins....
> 
>From a programmer's point of view you are right, but for the non-programmer
user all
those concepts are not important. They only care about the simple syntax
(V.. happens
to have).


Jonathan Revusky-3 wrote:
> 
> Who would be interested in this? Why wouldn't they just use FreeMarker? 
> 
Because of the V.., (better said  *.wm)  syntax. 
It is of course very primitive, but for the non-programmers already the
upper limit they're able (or ready) to learn.
"Less is not more", but just what they need (and feel confortable with).


Jonathan Revusky-3 wrote:
> 
> I have heard nothing from the guy who supposedly wanted this. An 
> interesting experiment nonetheless.
> 
Sorry, but I'm not ready with the tests I promissed.
I'm working on a compatibility test suite (and I had to start with the
documentation first to get the approval :) ).
It is not bound to this velocity bridge, but it's generic to use with any
framework that could produce
compatible results with Velocity, so that when it's there, with minimal
effort to be able to test that compatibility.



Jonathan Revusky-3 wrote:
> 
> I think it could be interesting to work up an alternative parser for 
> that syntax and offer it. Also, by breaking out the syntax like that, it 
> would clean out a lot of FreeMarker's basic design. So it's an idea... 
> 
Of course, this sounds much better since than the V.. dependency would
be 100% gone :).


Jonathan Revusky-3 wrote:
> 
> but I don't think that a crippled FreeMarker that uses Velocity syntax 
> is really very appealing.
> 
I suppose this is because you think all the time like a programmer :).
If you would have to deal with non-programmers (and thier number is much
higher than ours) you would quickly see where are their limits :).

Demetrios.
-- 
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