I am using a plugin called Post Snippets.
According to the documentation, it can substitute variables, such as {url} within the snippets.
http://wordpress.org/extend/plugins/post-snippets/
I am unclear how to assign values from within a specific post to a variable.
I tried using exec-PHP, and used the following:
[exec]url = "domain.com";[/exec]
But the snippet registered no value for {url}.
How can I assign, from within a post, the value to a variable so that I can use it as described?
The Variables in Post Snippets (WordPress Plugin) is a comma seperated value. When you use the snippet-insert button in the post/page editor, you can set those.
An example of this is given on the homepage of the plugin, there is even a screenshot demonstrating that. Please read the documentation first.
Those Post Snippet Variables are totally unrelated to PHP variables. I think that’s just the thing you missed. You were looking in the wrong direction.