README: remove extraneous parentheses

[shimaore]

If I understand things properly,

• the parentheses in the first example are optional (if they are present the value will be static; this doesn't break the example but I feel it is misleading for first-timers),
• while the parentheses under "Automatic Updates" and the section on Components are incorrect (the values would be static while the examples want to demonstrate dynamic updates).

Obviously if my understanding is incorrect I'm happy to learn!

[adamhaile]

Hi Stéphane -- Not quite. Any signals dereferenced by code inside the brackets creates a dependency. So <span>{text()}</span> will update if text() changes. To make it static you'd have to move the dereference all the way out of the brackets, something like var _text = text(); ... <span>{_text}</span>.

This is possible because the compiler translates the JSX expression to something like ...

S(() => {
    Surplus.content(span, text());
});

... not -- and I think this is what you were thinking -- something like ...

Surplus.content(span, text());

(Surplus.content() is a runtime utility to set the contents of an element.)

Since the contents of the {...} expression is wrapped in a lambda which forms the body of a computation, the dereferencing of text() is captured and is dynamic.

Make sense? -- Adam

[shimaore]

Hi Adam,

Oh I see now, it's actually better to use the function call (so: add the parentheses) otherwise the wrapping happens at runtime instead of compile-time.

(I guess I'm as confused as others about the automatic dependency tracking, although it is reminiscent of knockout. Because of the functional approach I was expecting something closer to flyd hence my mistake.)

I definitely need to read the code of S much closer. ☺