I should explain my question a little more.
What I wanted to in pseudo code was something like this:
If (this_tiddler_has_tag("foo")) {
<h1>Hello I'm a foo</h1>
<button>Click</button>
} else {
<h1>Hello</h1>
}
Now there are 10 quadzilion template languages that can do this.
For example in django I might write
{% if has_tag("foo") %}
<h1>hello I'm a foo</h1>
...
{% else %}
<h1>hello<>h1>
{% endif %}
Pretty easy for anybody to understand - the django filter language is
described
at https://djangobook.com/basic-template-tags-filters/
(I'm not recommending django BTW - it's for the example)
The point is this type of syntax (call it django, php, etc.) is
vary familiar.
The <$list ..> syntax is as far as I can see ,what in many other languages
would be called
a list comprehension. Some language call these iterators.
I'd have expected a syntax link this:
<? for i in tiddlers_with_tag("foo") && tiddlers_with_tag("bar") ?>
<h1> ${i).title </h1>
<? endfor ?>
The TW equivalent has no variable i but seems to have an implicit variable
<<currentTiddler>> which is somewhat confusing.
As it is the similarity to HTML leads me to believe that the widget is
something like HTML (which it is not) - rather than a programming
language construct (which it is)
Strange syntax frightens beginners off - they feel happier
with familiar syntax.
On Monday, 19 March 2018 00:18:09 UTC+1, Jed Carty wrote:
>
> Wikitext isn't a Turing completely language, there aren't necessarily
> equivalents to what you are talking about. TiddlyWiki has very few
> attributes of a normal programming language, I don't think that tiddlywiki
> has the equivalent of a procedure from an imperative programming language.
> You can use javascript in tiddlywiki, but in that case it is javascript,
> not anything specific to tiddlywiki.
>
>
Actually wikiText could be Turing complete (and possible easier to
understand) if you had a syntax
that is vaguely similar to conventional syntax. ie you have a set of things
like this:
<? if ?>
...
<? else ...?>
<? endif ?>
The problem with the widget syntax is that all the arguments
get squashed into the head of the definition as keyword arguments
and not placed syntactically in the body of the statement.
If you had a syntax that reminded people of PHP you'd suddenly get
thousands of new enthusiasts.
Unfamiliar syntax scares off beginners - been there - done that
Cheers
/Joe
> TiddlyWiki does allow a lot of flexibility using recursion and, in my
> opinion at least, is something like declarative or functional programming.
>
>
> That said, you can do if-then-else using lists like this:
>
> <$list filter='condition statement' emptyMessage=<<Else result>>>
> Than result
> </$list>
>
> as long as you can define your condition as a filter that returns one or
> more results if true and no results if false. If you are comfortable with
> set theory than the filtering operations in tiddlywiki are very powerful.
>
I'm familiar with list comprehensions - in fact my first WOW moment was
when I realised
that <<list-links "[tag[xyz]]">> was just predicate logic with a funny
syntax.
The filter is "just" a limited sub-set of Prolog with a kind of
list-comprehension syntax.
The feeling I get playing with tiddly wiki is that it is some kind of
beautiful mixture of
smalltalk and prolog and the browser DOM - all mixed together in very
clever ways.
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