Re: plists, alists, and hashtables

[Rusi <rustompmody@gmail.com>]

On Friday, August 7, 2015 at 12:50:20 AM UTC+5:30, Stefan Monnier wrote:
> > In short a map is the fundamental data structure.¹
> 
> Beware: there are maps and then there are maps.
> E.g. Javascript's objects are maps (typically thought of as being
> implemented as some kind of hash-tables), yet Javascript also comes with
> hash-tables.

Thats the whole point
Python: Zen on python makes a big todo about namespaces because they work 
uniformly and nicely for objects, classes, modules... All of which are
dictionaries ie maps
Lua: Only one collection data structure -- the table.
Tables made without explicit keys just use 1,2,3 etc ie normal lists with
the expected convenient lists syntax. Brings me to...
SQL: All of sql hangs around relations. May be called 'relation' but they
are invariably key → tuple maps

Finally a more 'fundamentalist' viewpoint:

Programmers write functions as their most primary activity
If they are algorithmic they are the functions that all programmers daily use
If they are just looked-up they are 'data-maps' -- for which a hash-table is 
a typical² data structure

IOW functions-as-code and functions-as-data are a primary dual
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¹ No attribution line...Assuming you are quoting me....
² If 90% of all maps/associations are smaller than 10-15, then a linear lookup 
would be clearly a win over more fancy (Pascal's point I think). My point is 
more that the *idea* of a map needs to be fundamental not the details of *implementation*