----- INTRODUCTION [1.1] ---------------------------------------------------
--[[                                                     author@churchianity.ca

    this is a library for using hexagonal grids in amulet/lua.
    it is extremely incomplete. the following list of features is 
    either implemented shoddily, or not at all. 

    if you want an actual good resource, go to [1.9].

----- COORDINATE SYSTEMS [1.2] ----------------------------------------------
    
    * as much coordinate manipulation as possible is done internally.
      depending on the task, uses either Axial, Cube, or Doubled coordinates.
    
    * three different ways of returning and sending coordinates:
        
        1) amulet vectors
        2) lua tables
        3) individual coordinate numbers
        
        so you can use what your graphics library likes best!

----- MAPS & MAP STORAGE [1.3]  -------------------------------------------------
    
    some map shapes: parallelogram, rectangular, hexagonal, triangular. (and more)
    * storage system based on map shape - see chart:
   
   ________________________________________________________________________
   |      SHAPE         :                MAP STORAGE                        |
   |------------------------------------------------------------------------| 
   |  parallelogram     :   unordered, hash-like OR ordered, array-like     |
   |  rectangular       :   unordered, hash-like OR ordered, array-like     |
   |  hexagonal         :   unordered, hash-like OR ordered, array-like     |
   |  triangular        :   unordered, hash-like OR ordered, array-like     |
   |  ring              :   ordered, array-like                             |
   |  spiral            :   ordered, array-like**                           |   
   |  arbitrary         :   unordered, hash-like                            |
   |________________________________________________________________________|
    ** note that a spiral map is just a hexagonal one with a particular order.


----- CONVENTIONS AND TERMINOLOGY [1.8] -----------------------------------------

    because so many different kinds of coordinate pairs, trios


----- RESOURCES USED TO DEVELOP THIS LIBRARY, AND FOR WHICH I AM GRATEFUL [1.9] -
    
    * https://catlikecoding.com/unity/tutorials/hex-map/
        -> unity tutorial for hexagon grids with some useful generalized math.

    * https://youtube.com/watch?v=fNk_zzaMoSs&list=PLZHQObOWTQDPD3MizzM2xVFitgF8hE_ab
        -> amazing series on linear algebra by 3Blue1Brown

    * https://redblobgames.com/grid/hexagons
        -> now THE resource on hexagonal grids on the internet. 
    
    * http://amulet.xyz/doc 
        -> amulet documentation.
  ]]