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{. and {: Extended

initial writing: 2001-10-22
last updated: 2004-10-26

The monads {. and {: are now defined as follows:

{.y 0{ 1{.y
{:y 0{_1{.y

Therefore, {.y gives the first item of y , or an item of fills if y has no items; likewise {:y gives the last item, or fills if y has no items. {.!.f and {:!.f specify that the fill should be the atom f .

Previously, {.y and {:y signalled an index error if y had no items.

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