Dollar sign ($) in widget attributes?

[amreus]

I see some widget's attributes start with a $ and some don't.  Does the $ have special meaning?

[amreus]

On further inspection, is it the action widgets and the macrocall widget which use the $attribute.  The rest do not.  That's easier to remember.

[TW Tones]

Amreus,

Often overlooked by people is the logical necessity of a prefix on some parameters, once you understand this you may find yourself identifying when the $ is likely to be used, rather than any need commit it to memory.

• In the case of the macrocall widget, what If I wanted to pass a parameter called name, type or output ? they would be confused with the widgets parameters, 
• so $name, $type and $output ensure the widgets own parameters stay out of the way.
• And you can also imagine when creating new tiddlers or fields the $ is often used for the same reason, so as to not limit the names of parameters that can be use.
• The new tiddler and set field and in fact all Action widgets must use $ for the very same reason.

As an experienced programmer I have learned there are good reason for a lot of things people perceive as exceptions or complexity, to actually be logical necessities. 

• You can see in this case the ability to have a prefixed parameter "$name" is essential in some widgets. 
• Unfortunately most documentation, for most systems, including programming languages, do not explain these logical necessities.
• An example is the the mathematical order of precedence in programming languages 4x(3x2+5), many languages document them as if they invented this, 
• however they were developed hundreds of years earlier in the field of mathematics
• By not recognising this history, people are forced to remember every detail "again", rather than rely on it mapping to historical standards.

Regards

Tones