DATATYPES is a block of value:
[end! unset! error! datatype! context! native! action! routine! op! function! object! struct! library! port! any-type! any-word! any-function! number! series! any-string! any-block! symbol! word! set-word! get-word! lit-word! refinement! none! logic! integer! decimal! money! time! date! char! pair! event! tuple! bitset! string! issue! binary! file! email! url! tag! image! block! paren!path! set-path!lit-path! hash! list!]