Optional partial inclusion / partial self referencing

support
1

Hello Hugo Community,

Is there a possibility to include a partial based on its existence or not?
I am willing to use this to “implement” a template inheritance mechanism with the standard Go template language.

The second question is whether it is possible to get information about the partial itself when included? What I am typically interested in is its filename at generation time.

Note: To scope things I am currently not interested in the other template engines as I want to have a syntax that is close to html design tools, can work with.

Regards,

Bram

2

Currently no. It would be possible to implement, of course, but it’s not on my list.

Isn’t that implied?

{{ partial "header.html" . }} {{/* ==> partial/header.html */}}
3

Hi Bjørn,

Thanks for your quick response.

I got kinda template “inheritance” working.
In the partials providing the overrides I use a “self-reference” to provide extends-functionality.

See example files below…

Driver script: _default/single.html

{{ if ne "" .Type }}
{{ .Scratch.Set "block" "extends" }}
{{ partial (printf "%s.html" .Type ) . }}
{{ end }}
{{ partial "layout.html" . }}

Base layout: partials/layout.html

<html>
<body>
	<header>
		{{ .Scratch.Set "block" "header" }} {{ if not (.Scratch.Get (printf "block-%s" (.Scratch.Get "block"))) }}
		<h1>{{ .Site.Title }}</h1>
		<ul>
			<li>
				<a href="/home/">Home</a>
			</li>
			<li>
				<a href="/posts/">Posts</a>
			</li>
		</ul>
		<hr/>
		{{ else }}{{ partial (.Scratch.Get (printf "block-%s" (.Scratch.Get "block"))) . }}{{ end }} 
	</header> 
	<div id="content-wrapper">
		{{ .Scratch.Set "block" "content" }} {{ if not (.Scratch.Get (printf "block-%s" (.Scratch.Get "block"))) }}
		<i>... please override ...</i>
		{{ else }}{{ partial (.Scratch.Get (printf "block-%s" (.Scratch.Get "block"))) . }}{{ end }} 
	<div> <!-- content-wrapper -->
	<footer>
		{{ .Scratch.Set "block" "footer" }} {{ if not (.Scratch.Get (printf "block-%s" (.Scratch.Get "block"))) }}
		<hr/>
		{{ else }}{{ partial (.Scratch.Get (printf "block-%s" (.Scratch.Get "block"))) . }}{{ end }} 
	</footer> 	
</body>
</html>

Extended layout: partials/page.html

{{ if eq "extends" (.Scratch.Get "block") }}
{{ .Scratch.Set "block-content" (printf "%s.html" .Type) }}
{{ end }}
{{ if eq "content" (.Scratch.Get "block") }}
	<h2>Page - {{ .Title }}</h2>
	<i>{{ .Description }}</i>
	<p>{{ .Content }}</p>
{{ end }}

Extended layout: partials/posts.html

{{ if eq "extends" (.Scratch.Get "block") }}
{{ .Scratch.Set "block-content" (printf "%s.html" .Type) }}
{{ end }}
{{ if eq "content" (.Scratch.Get "block") }}
	<h2>Post - {{ .Title }}</h2>
	<i>{{ .Description }}</i>
	<p>{{ .Content }}</p>
{{ end }}

Note: In a similar way I implemented this for the list page leaving the layout.html untouched.

Best regards,

Bram

1 Like
4

I have put it to the test with a template generated by bootstrapstudio.com.

With this pattern it was really quickly to incorporate the template as I just had to identify and override the placeholders.

Example: http://hugo.bemsite.nl/

5

Interesting.

Today I am focussing on something that Hugo can’t do with Go templates?!

But if you did this with Hugo, the above isn’t entirely true … :slight_smile:

1 Like
6

You are totally right :wink:

I wrote that part before I started to experiment with the idea.

But now being able to work around this way, helps me to stay with Hugo as generator. Especially for more complex templates I like to have most of the layout in one file and I also dislike to repeat header/footer includes for different types of bodies. Potentially I should also be able to follow a similar approach with the {{ render }} command, but I think I will end up with same kinds of tricks to deal with default content when a block is not overridden.