[tw5] How do I use a URL in a macro?

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#1

Hello all,

I’m having trouble understanding why a simple macro I wrote doesn’t work properly:

\define todoLink(url, name:"Link")
<a href="$url$" class="tc-tiddlylink-external" target="_blank" rel="noopener noreferrer">$name$</a>
\end

If I use <<todoLink http://foo.org bar>> to call my shiny new macro, the first parameter seems to be completely ignored:

<a href="bar" class="tc-tiddlylink-external" target="_blank" rel="noopener noreferrer">Link</a>

On the other hand, if I use the <$macrocall> syntax, like <$macrocall $name="todoLink" url="http://foo.org" name="bar"/>, I get the expected behavior.

bar

Ultimately, I’ll be using this macro in tiddlers with a url field, so I _think I’ll have to use the <$macrocall> syntax. But I feel like this behavior will bite me in the future. Why does first method of calling the macro produce incorrect output, and why does the second work?

I can make the first method work by putting the URL in quotes, but I would like to avoid that in general because it’s more typing :): <<todoLink "http://foo.org" bar>>. Why are the quotes required? I thought macro expansion substituted text without treating the macro inputs as WikiText?

My browser is Opera 78.0.4093.184 on Windows 10, and my TiddlyWiki version is 5.1.21. Thanks for any help!

#2

The <<macroname param param param>> syntax, in addition to handling unnamed parameters, also recognizes named parameters, using name:value.
Thus, a value like http://foo.org is parsed as a parameter named “http”, with a value of “//foo.org”. By enclosing it in quotes, it avoids the named parameter parsing and passes it into the macro as a single parameter value

So… you can use the quotes to bypass the parameter name parsing:
<<todoLink "http://foo.org" bar>>
or, you can add a parameter name, like this:
<<todoLink url:http://foo.org bar>>

Either way, it’s going to be “more typing” (but only a little). Still, its less typing than the full <$macrocall ...> widget syntax.

-e

#3

Thank you, your explanation it makes it very clear what’s going on. Whoops :D!

Either way, it’s going to be “more typing” (but only a little). Still, its less typing than the full <$macrocall ...> widget syntax.

In this case, I will be using the <$macrocall ...> syntax because I want to create a template tiddler using tm-new-tiddler. This template contains wikitext which field-transcludes a URL field. However, if I want to create a generic macro for links where I might want to specify the URL scheme, I know to watch out for my colons this time :D!