Managing Attributes in the Button Widget Actions

[kookma]

1. Open https://tiddlywiki.com/prerelease/
2. Create a new tiddler with below script

\procedure doTest(a) 
<$action-setfield $tiddler=Test $filed=text $value=<<a>> /> 
\end

<$button actions=<<doTest 100>> >
Button 1: {{Test}}
</$button>

<$button>
<<doTest 200>>
Button 2: {{Test}}
</$button>

Button 1 uses actions attributes and set the value of text field of Test tiddler to 100
Button 2 uses in-body actions and set the value of text field of Test tiddler to 200

Why button 1 does not work? Look at the header: <$button actions=<<doTest 100>> >
Why my action procedure does not handle a correctly?

[pmario]

Because, in the first procedure call <$button actions=<<doTest 100>> > the proc <<doTest 100>> is not evaluated. Wikitext / TiddlyWiki is a "text substitution engine" and not a programming language.

Calling <$button actions=<<doTest 100>> > is the same thing as if you call it like this:

<$button actions="""<$action-setfield $tiddler=Test $filed=text $value=<<a>> />"""  >

So it does not know about the parameter 100

---

If you call it as follows, it works.

<$button actions="""<<doTest 100>>""" >

[pmario]

Check this out

\procedure variable() 123

\procedure doTest(a) 
<$action-setfield $tiddler=Test $filed=text $value=<<a>> /> 
\end

\procedure parameterVariable()
<$macrocall $name=doTest a=<<variable>> />
\end

<$button actions=<<parameterVariable>> >
Button 1: {{Test}}
</$button>

---

Optimized

\procedure variable() 123

\procedure doTest() 
<$action-setfield $tiddler=Test $filed=text $value=<<variable>> /> 
\end

<$button actions=<<doTest>> >
Button 1: {{Test}}
</$button>

Hope that makes sense

[kookma]

Thank you, Mario, for your detailed explanation. I understand the magic behind """<<doTest 100>>""".

[Jermolene]

Hi @kookma

Why button 1 does not work?

The most concise explanation is that the "actions" attribute is being set to the value of a procedure. But procedures are not wikified in this situation, instead the plain text of the procedure is used as the attribute value. The parameters of the procedure will be ignored too.