Tuesday, November 28, 2017, 8:43:49 PM, Denis Bredelet wrote:
> Hi Daniel,
>
>> On 28 Nov 2017, at 15:45, Jacques Le Roux <[email protected]>
>> wrote:
>>
>> Le 28/11/2017 à 16:43, Jacques Le Roux a écrit :
>>>
>>>
>>> Le 28/11/2017 à 10:45, Daniel Dekany a écrit :
>>>> This problem comes up again and again: the ${exp} syntax clashes with
>>>> the syntax of the thing the user wants to generate. So I believe we
>>>> need a Configuration option to address this. Something like
>>>> cfg.setInterpolationSyntax(FOO_INTERPOLATION_SYNTAX), and also
>>>> <#ftl interpolationSyntax="foo">.
>>>>
>>>> Like any syntax option, this is potentially confusing for users and
>>>> problem for tools, but I don't think there's a way around this. Users
>>>> have to deal with those clashing ${}-s somehow, and certainly an
>>>> in-house hack will be worse and even more confusing. (Surely they can
>>>> write ${'$'}{foo} or use #noparse, but if you need a lot of those,
>>>> then it's obviously not an acceptable workaround.)
>>>>
>>>> So, what the syntax would be? Some of my ideas:
>>>>
>>>> - {{exp}} is probably the nicest. For the same reason it potentially
>>>> clashes with something yet again, though I guess it's unlikely
>>>> enough that neither ${exp} nor {{exp}} works for you.
>
> Mustache style, in fact I would choose that other the default :-)
>
>>>> - @{exp}. It's similar to ${exp}, which I think is an advantage.
>>>> There's however a very small but still real chance that for someone
>>>> both ${} and @{} clashes with what they want to generate, because
>>>> using <someChar>{name} is somewhat popular.
>>>>
>>>> - #{exp}. That looks like the natural choice as we use # in tags as
>>>> well (also @, though). The reason I don't like it is that
>>>> we already have #{exp} in the standard syntax, but it's deprecated.
>>>> That's not a problem technically, as you can say that if you select
>>>> the #{} syntax, then it's not deprecated, and ${} will be treated
>>>> as static text. But now if someone sees #{exp}, they can't tell if
>>>> the template uses a deprecated syntax, or it uses the alternative
>>>> interpolation syntax. Also it's perhaps more likely that for someone
>>>> both ${} and #{} clashes (e.g. in the case you generate JSF JSP-s),
>>>> than that that both ${} and @{} clashes.
>>>>
>>>> - <=exp> and [=exp] depending on if you are using square- or
>>>> angle-bracket tag syntax. Look somewhat exotic... which also means
>>>> that hopefully it won't clash with anything.
>>>>
>>>> There's also the idea that we just let the user specify any separator,
>>>> like `cfg.setInterpolationStart("@{"); cfg.setInterpolationEnd("}")`.
>
> How about just:
>
> cfg.setInterpolationPrefix("@")
>
> If the start character is "{" then use {{ }}, else use #{ } or @{ } or
> whatever you choose.
The problem is that JavaCC doesn't really support such things. The
syntax is static in it. But we could hardwire all the sane symbols
into it (something like $@#%&), and then decide on runtime if we want
to change that token (like a "@{" token) to static text.
BTW, this reminds me that sometimes the problem is using "{" itself.
Some syntaxes (like RTF and Jira/Confluence) reserve that character,
and so no mater what character you put before it, it's still clashing.
And even {{exp}} has the same problem. So it seems that we need an
additional (or, the only alternative) syntax that doesn't use "{".
<=...> and [=...] comes into mind (though they are a bit complicated
as they depend on the tagSyntax as well).
> — Denis.
>
>>>> But if all kind of random syntax is possible, it's harder for users to
>>>> figure out what's going on (their syntax isn't mentioned in the
>>>> Manual, and nobody on StackOverlfow recognizes it either), and it's
>>>> more difficult to support that in tools as well. So I believe it's
>>>> better for everyone if there's one, or maybe two standard
>>>> alternatives. (Not to mention that I don't yet see how to implement
>>>> such a runtime-configured syntax with the current JavaCC-based parser.
>>>> Probably it would be a horrid hack if possible at all.)
>>>>
>>>> Opinions, ideas?
>>>>
>>>
>>>
>> Oops wrong button => blank message :/
>>
>> I also prefer {{exp}} for the simple reason that it reminds me Jira and of
>> course also for the reasons you explained
>>
>> Jacques
>>
>
>
--
Thanks,
Daniel Dekany
