Hi Folks,
The recent discussion of un-initialized list element referencing
reminded me of a typo in the draft of the 2nd edition of Alan Corre's
Icon Programming for Humanists.
On page 43, in example code of procedure printout()
# Arrange info in columns and figure letter total
write(right(n,2),right(1[n],12))
the example intends to reference an element of a list identified by
letter 'l' , as in l[n] .
But, square brackets also reference positions within strings.
The examples below of implicit type conversion may be diverting; if not,
please forgive this enthusiastic spam for Icon, Unicon, and Icon
Programming for the Humanities.
procedure main()
# '1' below represents the digit one, not the letter 'l'.
if 1[1] = 1 then# numerical comparison
write(1[1] = 1)
if 1[1] == 1 then # lexical comparison
write(1[1] == 1)
if 1[1] === 1 then# value and type comparison
write(1[1] === \1\)
end
produces:
1[1] = 1
1[1] == 1
1[1] === 1
Regards, Alan B Saichek
Dear friends,
A draft of the 2nd edition of Alan Corre's Icon Programming for
Humanists is available for public comment;
a link is on the Jeffery Systems page, under Books at unicon.org. We
would appreciate corrections.
Alan has generously contributed to the new edition of his book, and
even more generously agreed that it should
be made available in free electronic form.
Cheers,
Clint
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