I was browsing the APL2 documentation, and came across the following code
(page 56, on the PDF here
<http://publibfp.boulder.ibm.com/epubs/pdf/h2110720.pdf>):
[0] Z←NAME GETW N
[1] ⍝ GET ITEMS N FROM THE TABLE NAMED NAME
[2] Z←''
[3] →('NOT A VALID TABLE NAME' *ERR*~(⊂NAME)∊TABLES)/0
[4] TAB←⍎NAME
[5] B←N∊TAB[;1]
[6] →0ρ('ITEM(S)'((~B)/N)'NOT FOUND')*ERR*~^/B
[7] →(~∨/B)/0 ⍝ EXIT IF NONE FOUND
[8] Z←(TAB[;1]∊N)⌿TAB
What is ERR here? It seems like a function that sets some error state? It
certainly looks like something useful to have. I can't think of any way I
could build this myself though.
Regards,
Elias
