From: Jim Date: Sun, 1 Feb 2015 18:20:15 +0000 (-0500) Subject: tweak week1 advanced X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=commitdiff_plain;h=defe9acbbc95965b07929c7a5b78e9d00a0526b3;ds=sidebyside tweak week1 advanced --- diff --git a/topics/week1_advanced_notes.mdwn b/topics/week1_advanced_notes.mdwn index 203a22fc..1f58f61a 100644 --- a/topics/week1_advanced_notes.mdwn +++ b/topics/week1_advanced_notes.mdwn @@ -99,7 +99,7 @@ If we get to the `y & ys` line in the pattern list, and the pattern-match succee ### As-patterns ### -Sometimes it's useful to bind variables against overlapping parts of a structure. For instance, suppose I'm writing a pattern that is to be matched against multivalues like `([10, 20], 'true)`. And suppose I want to end up with `ys` bound to `[10, 20]`, `x` bound to `10`, and `xs` bound to `[20]`. Using the techniques introduced so far, I have two options. First, I could bind `ys` against `[10, 20]`, and then initiate a second pattern-match to break that up into `10` and [20]`. Like this: +Sometimes it's useful to bind variables against overlapping parts of a structure. For instance, suppose I'm writing a pattern that is to be matched against multivalues like `([10, 20], 'true)`. And suppose I want to end up with `ys` bound to `[10, 20]`, `x` bound to `10`, and `xs` bound to `[20]`. Using the techniques introduced so far, I have two options. First, I could bind `ys` against `[10, 20]`, and then initiate a second pattern-match to break that up into `10` and `[20]`. Like this: case [10, 20] of [ys, _] then case ys of