[antlr-interest] Able to emulate java.text.ChoiceFormat ?

Mon Nov 26 03:24:19 PST 2007

(Sorry for following up on my own posting - but there's something more I wanted to say ...):

Christopher, I'm not really sure that you can fundamentally solve the translation problem without "programming" (i.e., doing more than writing templates).

Let's assume you split your text generation according to the conditions n=0, n=1, n>1. However, there might be a natural language where the phrase for n=2 is different from other phrases (there have been languages like this - in addition to singular and plural, they had a form called "dual"; I think ancient Greek was such a language; and - don't laugh - the Bavarian dialects have some left-over dual word forms... but I digress ;-) ).

However, if your information-providing class only has property for checking "Zero", "One", "More" (as in my example), you'll never find out whether there are exactly two - and you are stranded again.

Here are more radical examples: The flection of words might change depending on the sex of a person associated with the thing; or even on the position where the thing is; etc.etc. Even if you know all this in your program, you'd have to expose the relevant knowledge to the "view" ("template") - which will at least confuse other people as to what of this plethora of properties they are supposed to use ...

So, you'll end up with a compromise in any case, wouldn't you?

Regards
Harald

-------- Original-Nachricht --------
> Datum: Mon, 26 Nov 2007 12:09:07 +0100
> Von: "Harald Mueller" <harald_m_mueller at gmx.de>
> An: "Christopher Brown" <chris77550 at gmail.com>
> CC: antlr-interest at antlr.org
> Betreff: Re: [antlr-interest] Able to emulate java.text.ChoiceFormat ?

> Hi -
> 
> well, I didn't invent this thing ;-) ...
> 
> ... but n = 0, n = 1, n > 0 are all *computations* (you need to know about
> numbers and comparison to evaluate these). So none of these things should
> be done in the view (the template). 
> 
> Also (I overlooked this in your original posting), passing of simple
> values (like fileSize) is not a good idea - you must always pass objects with
> properties (that's StringTemplates "type" system at work here ...).
> 
> So, provide properties in your class to find out what to do:
> 
> public class FileInfo {
>     public string getFileName() { ... }
>     public int getFileSize() { ... }
>     public boolean isZeroByteFile() { ... } // not necessary below - but
> would be in your three-way text creation example
>     public boolean isOneByteFile() { ... }
> }
> 
> Now, your template could be:
> 
> fileInfo(fi) ::= <<
> File $fi.fileName$, $fi.fileSize$
> $if(fi.oneByteFile)$byte$else$bytes$endif$.
> >>
> 
> (I am not sure I did this perfectly - I have not used Java+StringTemplate
> for a year or so, only C#, so maybe I did something wrong with the implicit
> get/is truncation ... But the concept is ok).
> 
> However, an even better (? - at least more interesting) way is template
> indirection:
> 
> enum FileSizeType { ZeroByteFile, OneByteFile, LargerFile }
> 
> public class FileInfo {
>     public string getFileName() { ... }
>     public int getFileSize() { ... }
>     public FileSizeType getFileSizeType() { ... }
> }
> 
> fileInfo(fi) ::= <<
> File $fi.fileName$, $fi.fileSize$ $(fi.fileSizeType)()$
> >>
> // note the parentheses around fi.fileSizeType! - 
> // this means to evaluate the property and THEN call 
> // the template whose name you COMPUTED! Here they are:
> 
> ZeroByteFile() ::= <<bytes>>
> OneByteFile() ::= <<byte>>
> LargerFile() ::= <<bytes>>
> 
> Now, there is no $if...$ any longer! OTOH, there is coupling of the
> template names to the enum constants; still, as there is always coupling from the
> view to the model (at least the properties must conform to each other!),
> this is not a principal problem ...
> 
> If you need to do *different* things based on the fileSizeType, it becomes
> a little more complicated; what we do is to have various "template name
> returning properties" in the model classes which follow strict rules. If
> someone wants to know about this, email me ...
> 
> I hope this helps!
> 
> Regards
> Harald
> 
> P.S. Once again: DO NOT pass simple values around in StringTemplate - even
> if it works (I dont know whether it does), it's not what is intended.
> 
> -------- Original-Nachricht --------
> > Datum: Mon, 26 Nov 2007 11:29:32 +0100
> > Von: "Christopher Brown" <chris77550 at gmail.com>
> > An: "Harald Mueller" <harald_m_mueller at gmx.de>
> > Betreff: Re: [antlr-interest] Able to emulate java.text.ChoiceFormat ?
> 
> > Hi Harald,
> > 
> > I can understand that the template engine shouldn't do computation,
> > but I'm not trying to do computation here.  And I'm not a GUI-builder
> > type person anyway, which is why StringTemplate.NET attracts me, now
> > that I'm doing a lot of C# work ;-)
> > 
> > For me, I'd like to be able to have one template per language.  A lot
> > of that targets user interfaces.  With ChoiceFormat, the templating
> > isn't computational (and I'd prefer something like ChoiceFormat's
> > syntax over if/else/endif), so it's easy to produce the three
> > following variations for "n" (the content of the square brackets is to
> > show the value, not part of any syntax):
> > 
> > [n=0] No records updated.
> > [n=1] One record updated.
> > [n>1] $n$ records updated.
> > 
> > [n=0] Aucune ligne n'a été modifiée.
> > [n=1] Une ligne a été modifiée.
> > [n>1] $n$ lignes modifiées.
> > 
> > That's not computation, that's just linguistically-correct output.
> > It'd be a shame to limit myself to phrases like "1 record(s) updated"
> > and "1 ligne(s) modifiée(s)", and it's certainly NOT model or
> > controller logic to start spitting out translated content (that's one
> > of the main aims of using a template engine).
> > 
> > That's the problem I'm trying to solve, not in any way about adding
> > more complex expressions and types to $if()$ !!!
> > 
> > So, is there anyway StringTemplate can help in providing
> > reader-friendly translations?
> > 
> > Thanks,
> > Christopher
> > 
> > 
> > On 26/11/2007, Harald Mueller <harald_m_mueller at gmx.de> wrote:
> > > Hi -
> > >
> > > The whole idea of StringTemplate is to separate "computation" from
> > "string building". Even the $if$ is in a way a concession - one could do
> > everything with lazily evaluated template names (things like $(abc)()$).
> > >
> > > The favored way is the definition of a clean interface which provides
> > all the attributes for the template; and do all the computation there.
> > >
> > > Stringtemplate is, as I see it, NOT an abstraction layer on a FIXED
> > value-providing machine (as are e.g. most report generators); rather, it
> is
> > intended that the templates evolve together with the accessed
> interfaces.
> > >
> > > In a way, Stringtemplate tries to do "MV(C)": It provides ONLY the
> VIEW
> > for a model; and like in MVC, the view itself is not supposed to compute
> > anything (even if some people with GUI builders in their hands prefer it
> > otherwise ...).
> > >
> > > Regards
> > > Harald M.
> > >
> > > -------- Original-Nachricht --------
> > > > Datum: Mon, 26 Nov 2007 10:35:23 +0100
> > > > Von: "Christopher Brown" <chris77550 at gmail.com>
> > > > An: antlr-interest at antlr.org
> > > > Betreff: [antlr-interest] Able to emulate java.text.ChoiceFormat ?
> > >
> > > > Hi,
> > > >
> > > > Is it possible to create templates that have the capabilities of
> > > > ChoiceFormat with StringTemplate (I'm using ST#3)?
> > > >
> > > > http://java.sun.com/javase/6/docs/api/java/text/ChoiceFormat.html
> > > >
> > > > For example, the following template doesn't work:
> > > >
> > > > fileInfo(fileName,fileSize) ::= <<
> > > > File $fileName$, $fileSize$ $if(fileSize>1)$bytes$else$byte$endif$.
> > > > >>
> > > >
> > > > (I'm using a group template file with the default lexer, not the
> angle
> > > > bracket one, as my target is HTML...).
> > > >
> > > > There only seems to be support for conditions based on string
> equality
> > > > or just non-nullity, not numeric comparisons.  I'm not wanting to
> add
> > > > computation into the view, but it's important in many (human)
> > > > languages to be able to vary the text along with a quantity, and I
> > > > don't want to hard-code parts of the template into the code that
> calls
> > > > it.
> > > >
> > > > Thanks,
> > > > Christopher
> > >
> > > --
> > > Psssst! Schon vom neuen GMX MultiMessenger gehört?
> > > Der kann`s mit allen: http://www.gmx.net/de/go/multimessenger
> > >
> 
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