I need help.
I need to use \"html/template\"\'s marking ({{.Title}}, example) in sub-files(\"article.html\", example in my text):
In your core.tmpl you have to use
{{template "article" .}}
If you don't specify the . at the end, the template will be executed with nil data. Specifying the . will pass the value of . to the invoked template.
Quoting from the text/template package documentation, Actions section:
{{template "name"}}
The template with the specified name is executed with nil data.
{{template "name" pipeline}}
The template with the specified name is executed with dot set
to the value of the pipeline.