self as used by interfaces and anonymous algorithms

2.28: adda/lexeme/self/for anon'algor's and interfaces:
. the word"self is useful in 2 contexts:
# anonymous algorithm:
it means the current algorithm,
# type`interface:
it means a current instance of that type;
eg, t.type: ( self!: defines a postix operator).
. if there is an algorithm in the header
(eg, to declare algorithms that won't change
for some reason...)
then the usual scope rules prevail .