gavinking

"Encoding of natural numbers at 
 type level."
interface Nat of Zero|Succ<Nat> {}
"The natural number `0`."
interface Zero satisfies Nat {}
"The natural number `N+1` for a
 given natural number `N`."
interface Succ<N>
        satisfies Nat
        given N satisfies Nat {}

gavinking

"Encoding of natural numbers at 
 type level."
interface Nat of Zero|Succ<Nat> {}
"The natural number `0`."
interface Zero satisfies Nat {}
"The natural number `N+1` for a
 given natural number `N`."
interface Succ<N>
        satisfies Nat
        given N satisfies Nat {}

gavinking

//a function that produces a tuple
[String, String?, String] parseName(String name) {
    value it = name.split().iterator();
    "first name is required"
    assert (is String first = it.next());
    "last name is required"
    assert (is String second = it.next());
    if (is String third = it.next()) {
        return [first, second, third];
    }

gavinking

/* Three generic functions for building tuple comparators. */

"A comparator function for any `Comparable` type."
Comparison comparator<Type>(Type x, Type y) 
        given Type satisfies Comparable<Type> 
        => x<=>y;
 
"A comparator function for instances of `[]`."
Comparison emptyComparator([] x, [] y) => equal;
 

gavinking

import java.util.concurrent {
    Callable,
    ScheduledThreadPoolExecutor
}

void execute(Integer numberOfTasks) {
    value n = 1G; // same number of iterations as Java
    value delta = 1.0 / n;
    value startTime = process.nanoseconds;
    value sliceSize = n / numberOfTasks;

gavinking

shared void run() => printAll { for (i in 0..50) fizzbuzz(i) };

String fizzbuzz(Integer i)
    =>   (i%15==0 then "fizzbuzz")
    else (i%3==0 then "fizz")
    else (i%5==0 then "buzz")
    else i.string;

void printAll({String*} strings) => print(", ".join(strings));

gavinking

Someone just told me that implementing an interface in F# is less vebose than in Ceylon. Let's see if that's true. Pick an example given on MSDN. (Yes, I know it's silly to make such trivial comparisons.)

F#

gavinking

Gavins-New-MacBook-Pro:ceylon-dist gavin$ ant -Dbuild-against=last-release clean-ide eclipse
Buildfile: /Users/gavin/ceylon-dist/build.xml

clean-ide:

siblings:

clean:

clean-item:

gavinking

"Finds the (last) longest substring that contains
 at most two unique characters"
String longest2UniqueCharSubstring(String s)
        => let (init = [[0, 0, 0, 0], 0, '\0', '\0'],
                mpos = s.fold(init)((acc,ch)
                     => let ([[mb,me,cb,ce],cb1,ch0,ch1] = acc,
                             ce1 = ce+1,
                             max = (Integer b, Integer e) 
                                 => me-mb > e-b then [mb,me,b,e] 
                                                else [b,e,b,e])

gavinking

shared String formatFloat(
        "The floating point value to format."
        Float float,
        "The minimum number of allowed decimal places.
         
         If `minDecimalPlaces<=0`, the result may have no
         decimal point."
        Integer minDecimalPlaces=1,
        "The maximum number of allowed decimal places.