X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=rosetta1.mdwn;h=a84719588b4242e5cbbbc1d6730daad686e42e8b;hp=1c42a1337c03686ed227e190918aa44a86ffa57b;hb=aa3fa8ee79bd50b6371da340227b2144026ae3a7;hpb=26c8d6da76887c3756f2ce856b03f490945814c0 diff --git a/rosetta1.mdwn b/rosetta1.mdwn index 1c42a133..a8471958 100644 --- a/rosetta1.mdwn +++ b/rosetta1.mdwn @@ -1,5 +1,7 @@ [[!toc levels=2]] +More details are also available on these [[two|/rosetta2]] [[pages|/rosetta3]]. (But some information is only discussed below; the others aren't supersets of this page.) + ## Can you summarize the differences between your made-up language and Scheme, OCaml, and Haskell? ## The made-up language we wet our toes in in week 1 is called Kapulet. (I'll tell you [the story behind its name](/images/randj.jpg) sometime.) The purpose of starting with this language is that it represents something of a center of gravity between Scheme, OCaml, and Haskell, and also lacks many of their idiosyncratic warts. One downside is that it's not yet implemented in a form that you can run on your computers. So for now, if you want to try out your code on a real mechanical evaluator, you'll need to use one of the other languages. @@ -215,7 +217,7 @@ Fourth, in Kapulet, `( - 10)` expresses λ `x. x - 10` (consistently with ( - 2) # ( - 2) 10 == 8 (0 - ) ( - ) (5, 3) - + and here are their translations into natural Haskell: @@ -517,6 +519,7 @@ Note there is no closing `end` or `}`. You can enclose the whole expression in p | 1 -> result1 | x -> resultx + The syntax for [[guards|topics/week1_kapulet_advanced#guards]] and [[as-patterns|topics/week1_kapulet_advanced#as-patterns]] also only varies slightly between these languages: # Kapulet @@ -779,7 +782,7 @@ Notice that this form ends with `end`, not with `in result`. The above is roughl pat1 match expr1; ... in ... # rest of program or library - + That is, the bindings initiated by the clauses of the `let` construction remain in effect until the end of the program or library. They can of course be "hidden" by subsequent bindings to new variables spelled the same way. The program: # Kapulet