masak

$ perl6 namer.p6
ahay	ahe	akak	ake	ane	apa	bib	bisu
bizi	bowuw	but	buxu	cub	cug	dirux	dotu
dozi	ehe	epe	gib	gito	guc	guf	hemaj
heya	ibo	ibogi	ibos	ico	iqic	iqo	itoto
ivi	iwiqi	ixod	ixot	izu	jek	lam	lap
lem	len	maj	meka	nak	obic	obif	ocigi
ocod	ocufo	odu	ogiv	ogu	osu	ovuw	owoxu
oxi	oxo	oxu	ozi	pala	pel	qig	qiq
qoci	qor	ric	riv	rof	rox	rus	soxo

masak

If the circles have the same center, they intersect at no point if they have different radius, or at all points if they have the same radius.

Leaving that case aside, we can assume without loss of generality that one circle is centered at (0, 0) and has radius 1, while the other one is centered at (x, 0) with x > 0 and has radius R with R ≥ 1. We're left with three cases.

• If R is outside the closed interval x-1..x+1, the circles don't intersect.

• If R is on either endpoint of that interval, x-1 | x+1, the circles intersect at exactly one point, either (+1, 0) or (-1, 0), respectively.

• Finally, if R is strictly inside the interval x-1..x+1, the two intersection points are of the form (cos ±α, sin ±α), where α satisfies (Pythagoras) R² == (x - cos α)² + sin²α == x² - 2 x cos α + cos²α + sin²α == x² - 2 x cos α + 1. Thus α = acos (x² - R² + 1)/(2 x).

masak

diff --git a/S03-operators.pod b/S03-operators.pod
index a6f3eb5..2d651b0 100644
--- a/S03-operators.pod
+++ b/S03-operators.pod
@@ -14,8 +14,8 @@ Synopsis 3: Operators
 
     Created: 8 Mar 2004
 
-    Last Modified: 18 Aug 2014
-    Version: 279

masak

#! /usr/local/bin/perl6
use v6;
# don't need to use warnings or strict
 
# original code had the class after the .new call; that doesn't work
# because of one-pass parsing
 
# kinda un-idiomatic to have a class name not start with a capital;
# but it *works*, so I'll keep it
class life {

masak

role Group {
    method elements { ... }
    method id { ... }
    method op($l, $r) { ... }
}

macro assert($fact) {
    quasi {
        die "FAILED: ", $fact.Str
            unless {{{$fact}}};

masak

class Conf {
    has @.boxes where *.all >= 0;
    method gist { "[$.boxes]" }
}

sub conf(@boxes) { Conf.new(:@boxes) }
sub n(Conf $c) { $c.boxes.elems }

sub REPL($line) {
    say "> $line";

masak

COMMIT="$1"
echo "${COMMIT:=HEAD}"
OLD_HEAD=`git rev-parse HEAD`

git reset --hard $COMMIT
git reset --mixed HEAD~
git commit --patch || (git reset --hard $OLD_HEAD && exit)
git checkout .
git rebase -X theirs $OLD_HEAD

masak

I noticed that in these two years, no-one had gone ahead an written a Haskell version of the task. So I went ahead and did it. Code below.

I had to learn a bit about Haskell date and calendar handling, looping, monads, and comprehensions before succeeding. But RosettaCode and #haskell were both good sports.

I've optimized for clarity. The isFriday condition doesn't need to be pulled out into its own function, but I felt it helped readability a bit.

import Data.Time.Calendar
import Data.Time.Calendar.WeekDate

isFriday :: Day -> Bool

masak

import Control.Monad
import Data.Time.Calendar
import Data.Time.Calendar.WeekDate
 
main = do
    forM_ [2012..2017] $ \year -> do
        forM_ [1..12] $ \month -> do
            let date = fromGregorian year month 13
            let (_, _, weekDay) = toWeekDate date
            when (weekDay == 5) (putStrLn . showGregorian $ date)

masak

Story: writing a blog post

    user selects "new blog post"
    app goes to "new blog post" screen
        screen stays active while the user edits it
    {{DONE}}
    user selects "publish post"
    {{SAVE}}
    app publishes post