X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=assignment8.mdwn;h=c954e955f249f5f3cf54c2f349ed2f710f962ea0;hp=cdb32e875beaa8cbab5f6e2171ce08f6814ae62e;hb=ad2f53317266fc3a57ba8dd05a0b90c55ef1d472;hpb=eb2fa58d13fb86ca9ae981a85864374df7d864a7 diff --git a/assignment8.mdwn b/assignment8.mdwn index cdb32e87..c954e955 100644 --- a/assignment8.mdwn +++ b/assignment8.mdwn @@ -73,11 +73,17 @@ is equivalent to: (if (test1 argument argument) + ; then result1 + ; else (if (test2 argument argument) + ; then result2 + ; else (if (test3 argument argument) + ; then result3 + ; else result4))) Some other Scheme details: @@ -90,7 +96,7 @@ * `(null? lst)` tests whether `lst` is the empty list * non-empty lists are implemented as pairs whose second member is a list * `'()` `'(1)` `'(1 2)` `'(1 2 3)` are all lists - * `(list)` `(list 1)` `(list 1 2)` `(list 1 2 3)` are the same lists + * `(list)` `(list 1)` `(list 1 2)` `(list 1 2 3)` are the same lists as the preceding * `'(1 2 3)` and `(cons 1 '(2 3))` are both pairs and lists (the same list) * `(pair? lst)` tests whether `lst` is a pair; if `lst` is a non-empty list, it will also pass this test; if `lst` fails this test, it may be because `lst` is the empty list, or because it's not a list or pair at all * `(car lst)` extracts the first member of a pair / head of a list