Generator expressions

A generator expression is a compact generator notation in parentheses:

generator_expression	::=	"(" test genexpr_for ")"
genexpr_for	::=	"for" expression_list "in" test [genexpr_iter]
genexpr_iter	::=	genexpr_for | genexpr_if
genexpr_if	::=	"if" test [genexpr_iter]

A generator expression yields a new generator object. The iterating values would be produced by considering each of the for or if clauses a block, nesting from left to right, and evaluating the expression to yield a value that is reached the innermost block for each iteration.

innermost
adj
1: being deepest within the self;
2: situated or occurring farthest within;