Scope of macros

[joearms]

I was wondering about the scope of macro definitions  ...

The scope of a macro appears to be 'in the current tiddler where it was defined

or any tiddler transcluded from the current tiddler'

Here are two tiddlers

Tiddler1Test is

   \define foo()

   say bar

   \end

   in tiddler 1 foo=<<foo>>

   {{Tiddler2Test}}

Tiddler2Test is

   in tiddler 2 foo = <<foo>>

Tiddler1 renders as

   in tiddler 1 foo=say bar

   in tiddler 2 foo = say bar

Which means the transclusion of Tiddler2 sees the macro - BUT

Tiddler2 viewed at the top level does NOT SEE the macro and renders as

 in tiddler 2 foo =

So how {{Tiddler2Test}} expands is dependent upon the context - so my explanation

of transclusion "it's like a spreadsheet" is not really true. It's like a spreadsheet but including

a cell from different places is not guaranteed to produce the same result.

Up to now, my expectation was that {{X}} always expanded to the same thing until the end

of the universe and not depending upon where it was called from.

Is the moral "don't use macros outside the tiddler where they were defined" or what should I be doing.

I seem to have broken some law of tiddly programming in the "thou shalt not ...." and ended up in the

"there will be gnashing of teeth and gnawing of bones" part of the system.

Cheers

/Joe 

[PMario]

 Hi Joe,

In TW macros are internally handled as variables, similar how the <$set widget defines them. <$set variables only work within <$set>  x  </$set>. macros do have a "tiddler-scope"

If you want to use macros defined in other tiddlers you'll need to import them.

see: https://tiddlywiki.com/#ImportVariablesWidget

The existing behaviour gives us a simple way to overwrite variable definitions. eg: to create user-defined download buttons. ...

have fun!

mario

[joearms]

On Monday, 17 December 2018 14:28:03 UTC+1, PMario wrote:

 Hi Joe,

In TW macros are internally handled as variables, similar how the <$set widget defines them. <$set variables only work within <$set>  x  </$set>. macros do have a "tiddler-scope"

If you want to use macros defined in other tiddlers you'll need to import them.

see: https://tiddlywiki.com/#ImportVariablesWidget

I was wondering how to do this.

Thanks

/Joe

[Ton Gerner]

Hi Joe,

Be aware of global macros: macro definitions tagged with $:/tags/Macro

See also https://tiddlywiki.com/#Macros

Cheers,

Ton

[Simon Huber]

Hi, the macros tagged $:/tags/Macro are imported in the page-template tiddler ($:/core/ui/PageTemplate) which makes them available within the story river and the sidebar and all sub-transcluded tiddlers...

PageTemplate

    import all $:/tags/Macros

    set some stuff

    transclude all sub-templates (sidebar,story ...)

    close stuff

close PageTemplate

you can import a macro defined in "Macro testtiddler" (which isn't tagged $:/tags/Macro)

using the <$importvariables filter="[[Macro testtiddler]]">

or

\import [[Macro testtiddler]]

in another tiddler