How can I pass variables between DRY templates and ncludes in Jekyll - variables

Question

I have a simple Blog site where the front page index is a list of posts, non truncated and rendered exactly like the individual pages.
I have the index page setup and working:
---
layout: default
---
<div>
{% for post in site.posts %}
{% include post/post.html %}
{% endfor %}
</div>
Where post/post.html contains the post layout using the post variable like so:
<article>
<header>
{% include post/title.html %}
{% include post/metadata.html %}
</header>
<div class="entry-content" itemprop="text">
{{ post.content }}
</div>
</article>
Now, on a specific post page, I want to reuse this include layout so that I can keep my code DRY, so I have the posts use the post.html layout (different from posts/post.html above):
---
layout: default
comments: true
---
{% include post/post.html %}
but the problem is that the include file expects a post variable to exist such post.content is how you access the content.
I have tried:
{% assign post = page %}
and that seems to be the right to pass a variable in, but page is not the right one as it renders as a markdown string instead of the html on the page.
So, how can I pass self -- or whatever is needed -- so that the include file does not need to be altered for the index page or the post page, thus sharing the same code?

Answer 1

While #David Jacquel's answer work, I found it to be unclean and a little verbose, though it did get me on the right track.
_includes/post/post.html swaps the {{ post.content }} for {{ body }}
<article>
<header>
{% include post/title.html %}
{% include post/metadata.html %}
</header>
<div class="entry-content" itemprop="text">
{{ body }}
</div>
</article>
_layouts/index.html now uses
{% assign body = post.content %}
{% include post/post.html %}
_layouts/post.html uses:
{% assign post = page %}
{% assign body = content %}
{% include post/post.html %}
Simple.

Answer 2

We can do it ! With some layout and variable passing.
Regular post use post layout :
---
layout: post
....
---
post content ...
A custom post use the custom_post layout (_layouts/custom_post.hmtl)
---
layout: custom_post
...
---
post content ...
The _layouts/custom_post.hmtl layout just calls our post include, passing the page variable :
---
layout: default
---
{% include post/post.html page=page %}
And finally the _includes/post/post.html conditionally assign the post variable if the page variable is set :
{% if include.page %}
{% comment %}
This only append in the custom_post view context
{% endcomment %}
{% assign post = include.page %}
{% endif %}
<article>
<header>
{% include post/title.html %}
{% include post/metadata.html %}
</header>
<div class="entry-content" itemprop="text">
{{ post.content }}
</div>
</article>