heads down
[Sun] Concentrating, usually so heavily and for so long that everything outside
the focus area is missed. See also hack mode and larval stage, although this
mode is hardly confined to fledgling hackers.
[Jargon File]
Nearby terms:
header « Head Normal Form « head normalisation
theorem «
heads down » head-strict » heap » heartbeat
head-strict
<theory> A head-strict function will not necessarily evaluate every cons
cell of its (list) argument, but whenever it does evaluate a cons cell it will
also evaluate the element in the head of that cell. An example of a head-strict
function is
beforeZero :: [Int] -> [Int]
beforeZero [] = []
beforeZero (0:xs) = []
beforeZero (x:xs) = x : beforeZero xs
which returns a list up to the first zero.
This pattern of evaluation is important because it is common in functions which
operate on a list of inputs.
See also tail-strict, hyperstrict.
(1995-05-11)
Nearby terms:
Head Normal Form « head normalisation theorem «
heads down «
head-strict » heap » heartbeat » heatseeker
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