Tuesday, July 4, 2017, 7:57:18 AM, Woonsan Ko wrote:
> On Wed, Jun 21, 2017 at 2:30 PM, Daniel Dekany <[email protected]> wrote:
>> Friday, June 16, 2017, 8:41:37 PM, Daniel Dekany wrote:
>>
>>> A problem in FM2 is that when calling a directive (as a macro), either
>>> all parameters are positional (`<@message "Hi" 2 />`), or all
>>> parameters are named (`<@message content="Hi" height=2 />`); you can't
>>> mix the two (`<@message "Hi" height=2 />`). Also you can't use named
>>> parameters for functions/methods, only for directives. Worse, core
>>> directives don't even use named parameters, but some keyword like
>>> `as`, `using`... their syntax is hard coded into the parser, which is
>>> not nice, and will be a problem for the custom dialects feature.
>>>
>>> I think that with the exception of a few core directives (see them
>>> later) all directive calls should be like this, if for now (in this
>>> thread) we ignore loop variables:
>>>
>>> <#name posPar1 posPar2 namedPar1Name=namedPar1Value
>>> namedPar2=namedPar2Value>
>>
>> An adjustment to the above... I think that we should require comma
>> between positional arguments (but not between positional and named
>> arguments and between named arguments):
>
> "but not between ..." means that a comma can be *optionally* placed
> between named arguments or between a positioned argument and a named
> argument, right?
I wouldn't allow that. If we do, then where to put comma becomes a
matter of taste, and the taste of individuals in the same project
differ, or for OS projects, whoever bumps into the templates might has
a different taste. So overall, you just end up with chaos, and if some
cares much, it's just unnecessary struggle (which of the 3
combinations is the Right Way). So I believe it's better overall if we
decide what's the right way for everyone... Especially as our taste is
based on more knowledge. FTL tags have this HTML-ish look-and-feel, so
naturally you write `<#foo n1=v1 n2=v2 m3=v3>`, and not
`<#foo n1=v1, n2=v2, m3=v3>`. So now, if we add a single positional
parameter, I think most will find it consistent like this:
`<#foo v0 n1=v1 n2=v2 m3=v3>` (like in `<@message "Hi" height=2 />`).
Still no comas anywhere. In the hopefully rare case when you have
multiple positional parameters, we unfortunately ran into ambiguity
issues, so then, and only then, and only between the positional
parameters you add commas. I think that's also matches common
conventions, where if you list something, you put commas *between* the
listed items, but not after the last one. Named parameters aren't
really listed (their order doesn't mater). So it's more logical to
only use comma where you must, not just a matter of taste.
BTW, I was never a fan of this HTML-ish look-and-feel, because of the
confusing differences; people keep writing `foo="${x}"` instead of
`foo=x`. But that's the FM tradition, so I try to remain consistent
with the original idea. (When we manage to separate the expression
syntax from the top-level syntax, I think I will try to introduce an
officially supported alternative, something like `#foo(v0, n1=v1,
n2=v2, m3=v3)`.)
> In other words, it is allowed to omit a comma between positional arg
> and named arg or between named args.
>
> Woonsan
>
>>
>> <#name posPar1, posPar2 namedPar1Name=namedPar1Value
>> namedPar2=namedPar2Value>
>
--
Thanks,
Daniel Dekany
