'''[dict]s are just like name value pair lists'''

Just like the results of [[[array] get]], so you can array set X [[[dict] filter]]

So, you can define a [proc] fred {args} and then immediately treat $arg as a [dict], if (and only if) the values passed have the form of a [dict] - no special processing is required (rather, the [shimmering] occurs in the background.

This is useful for passing named arguments to a [proc], sort of like the various options packages:  [[[dict] get $args -option]] will fetch any value passed as ''-option value''.

'''[[[dict] with]] alters the enclosing scope'''

So if you have a [dict] X, [[[dict] with X {}]] will construct and initialize variables with the same names and values as X's contents.

This is useful for passing around collections of named values.