Well, right. Tcl was an early example of a trend where key data structures were built into languages and fairly well encapsulated as "one size fits all" abstrac

Well, right. Tcl was an early example of a trend where key data structures were built into languages and fairly well encapsulated as "one size fits all" abstractions. Computers had become fast enough that for many purposes you didn't have to build a custom list or hash table. That all seems normal to us now, but it was uncommon back then.