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<DIV><FONT size=2 face="Courier New"><SPAN class=668574516-26082010>See
below,</SPAN></FONT></DIV>
<DIV><FONT size=2 face="Courier New"><SPAN
class=668574516-26082010>Jos</SPAN></FONT></DIV>
<DIV><FONT size=2 face="Courier New"><SPAN
class=668574516-26082010></SPAN></FONT> </DIV>
<DIV><FONT size=2 face="Courier New"><SPAN class=668574516-26082010>In
definitions window</SPAN></FONT></DIV>
<DIV><FONT size=2 face="Courier New"></FONT> </DIV>
<DIV><FONT face="Courier New"><FONT size=2>#lang typed/racket <BR>(: map
<BR> (All (C A B ...) <BR>
((A B ... B -> C) (Listof A) (Listof B) ... B
<BR>
->
<BR>
(Listof C)))) <BR>(define (map f as . bss) <BR> (if (or (null? as)
<BR> (ormap null? bss))
<BR> null <BR> (cons
(apply f (car as) (map car bss)) <SPAN
class=668574516-26082010> ; These to
lines</SPAN><BR>
(apply map f (cdr as) (map cdr bss))))) <SPAN class=668574516-26082010> ;
are highlighted</SPAN></FONT></FONT></DIV>
<DIV><FONT size=2 face="Courier New"></FONT> </DIV>
<DIV><SPAN class=668574516-26082010><FONT size=2 face="Courier New">Run, then in
interactions window:</FONT></SPAN></DIV>
<DIV><FONT size=2 face="Courier New"></FONT> </DIV>
<DIV><BR><FONT size=2 face="Courier New">Welcome to DrRacket, version
5.0.1.3--2010-08-19(e55f0cade1d47b2edbc65e7dd61ddce2041814af/a)
[3m].<BR>Language: typed/racket.<BR>. Type Checker: Polymorphic function map
could not be applied to arguments:<BR>Domain: (A B ... B -> C) (Listof A)
(Listof B) ... B<BR>Arguments: (All (a b) (case-lambda ((Pairof a b) -> a)
((Listof a) -> a))) (List (Listof B) ... B)<BR> in: (map car bss)<BR>.
Type Checker: Bad arguments to function in apply:<BR>Domain: A B ...
B<BR>Arguments: A Nothing *<BR> in: (apply f (car as) (map car bss))<BR>.
Type Checker: Polymorphic function map could not be applied to
arguments:<BR>Domain: (A B ... B -> C) (Listof A) (Listof B) ...
B<BR>Arguments: (All (a b) (case-lambda ((Pairof a b) -> b) ((Listof a) ->
(Listof a)))) (List (Listof B) ... B)<BR> in: (map cdr bss)<BR>. Type
Checker: Bad arguments to polymorphic function in apply:<BR>Domain: (A B ... B
-> C) (Listof A) (Listof B) ... B<BR>Arguments: (A B ... B -> C) (Listof
A) Nothing *<BR> in: (apply map f (cdr as) (map cdr bss))<BR>. Type
Checker: Summary: 4 errors encountered in:<BR> (map car bss)<BR>
(apply f (car as) (map car bss))<BR> (map cdr bss)<BR> (apply map f
(cdr as) (map cdr bss))<BR>> <BR></FONT></DIV>
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