Macro to differentiate between pages on different paths

When there is just one file called `index.html` this works fine:

```
$ cat header.html
{{#ifpage 'index'}}
You are at the home page
{{/ifpage}}
```

But when there are multiple directories with an `index.html` per directory, this code need to be enhanced (but how?)

The request is for some kind of differentiator to indicate the path to the file. The result might be something like this:

```
$ cat header.html
{{#ifpage '/index'}}
You are at the home page
{{/ifpage}}

{{#ifpage '/articles/index'}}
You are in the articles section
{{/ifpage}}

{{#ifpage 'index'}}
You are on some random page named index
{{/ifpage}}

```