Various constructions express a comparison between two arguments.
When the second argument (the point of reference) is adpositionally marked, ComparisonRef is used, regardless of its complement’s syntactic type:
See further examples at ComparisonRef.
In an as—as comparison, the scene role of the first argument (the object of the first as) is the role that would be operative if the construction were removed and only the first argument remained: e.g., I stayed as long as I could → I stayed long. The function of the first as is always Extent to reflect that it marks the degree on a scale:
See #001 above.
Whole is used for the superset or gestalt licensed by a superlative:
See more at Whole.