Zebra puzzle: Difference between revisions

Line 2,587:

=={{header|FormulaOne}}==

// First, let's give some variables some values:

// First, let's give some type-variables some values:

Nationality = Englishman | Swede | Dane | Norwegian | German

Colour = Red | Green | Yellow | Blue | White

Line 2,598:

We use injections to make the array-elements unique.

Example: 'Pet' is an array of unique elements of type 'Domestic', indexed by 'Nationality'.

In the predicate 'Zebra', we use this injection 'Pet' to define the array-variable 'pet'.

In the predicate 'Zebra', we use this injection 'Pet' to define the array-variable 'pet' as a parameter if the 'Zebra'-predicate.

The symbol used is the '->>'. 'Nationality->>Domestic' can be read as 'Domestic(Nationality)' in "plain array-speak";

the difference being that the elements are by definition unique.

the difference being that the elements are by definition unique (cf. 'injective function').

So, in FormulaOne we use a formula like: 'pet(Swede) = Dog', which simply means that the 'Swede' (type 'Nationality')

has a 'pet' (type 'Pet', ~~which is~~ of type 'Domestic', indexed by 'Nationality'), which appears to be a 'Dog' (type 'Domestic').

has a 'pet' (type 'Pet', of type 'Domestic', indexed by 'Nationality'), which appears to be a 'Dog' (type 'Domestic').

Or, one could say that the 'Swede' has been mapped to the 'Dog' (Oh, well...).

}

Line 2,643:

{ 5. The green house is immediately to the left of the white house: }

{ The local predicate 'LeftOf' determines the order: }

{ The local predicate 'LeftOf' (see below) determines the order: }

LeftOf(green_house, white_house, order) &

Line 2,655:

smoke(yellow_house) = Dunhill &

{ 9. In the middle house they drink milk: }

{ 9. In the middle house (third in the row) they drink milk: }

drink(order(Third)) = Milk &

Line 2,674:

smoke(German) = Prince &

{15. The Norwegian lives next to the blue house: }

{15. The Norwegian lives next to the blue house

{10. The Norwegian lives in the first house,

Cf. 10. "The Norwegian lives in the first house", so the blue house is the second house: }

⚫

houseColour(order(Second)) = Blue &

so the blue house is the second house }

⚫

houseColour(order(Second)) = Blue &

{16. They drink water in a house next to the house where they smoke Blend: }

Line 2,735:

Line 2,734:

pet(cat_keeper) = Cat &

pet(neighbour_dunhill_smoker) = Horse &

houseColour(Englishman) = Red &

pet(Swede) = Dog &

Line 2,765:

Line 2,763:

<pre>

houseColour = [ {Englishman} Red, {Swede} White, {Dane} Blue, {Norwegian} Yellow, {German} Green ]

houseColour=[ {Englishman} Red, {Swede} White, {Dane} Blue, {Norwegian} Yellow, {German} Green ]

pet = [ {Englishman} Birds, {Swede} Dog, {Dane} Horse, {Norwegian} Cats, {German} Zebra ]

pet =[ {Englishman} Birds, {Swede} Dog, {Dane} Horse, {Norwegian} Cats, {German} Zebra ]

smokes = [ {Englishman} PallMall, {Swede} BlueMaster, {Dane} Blend, {Norwegian} Dunhill, {German} Prince ]

smokes =[ {Englishman} PallMall, {Swede} BlueMaster, {Dane} Blend, {Norwegian} Dunhill, {German} Prince ]

drinks = [ {Englishman} Milk, {Swede} Beer, {Dane} Tea, {Norwegian} Water, {German} Coffee ]

drinks =[ {Englishman} Milk, {Swede} Beer, {Dane} Tea, {Norwegian} Water, {German} Coffee ]

order = [ {First} Norwegian, {Second} Dane, {Third} Englishman, {Fourth} German, {Fifth}, Swede ]

order =[ {First} Norwegian, {Second} Dane, {Third} Englishman, {Fourth} German, {Fifth}, Swede ]

</pre>