World Cup

Sunday, June 22, 2014

Many people are watching the FIFA World Cup 2014 that is going on right now in Brazil. A few days ago, someone posted a gist for following the World Cup in six lines of Python 3. Several people tried to improve it, down to four lines, then down to one or two lines of code.

Without worrying too much about lines of code, here is something similar in Factor.

: worldcup. ( -- )
    "https://worldcup.sfg.io/matches" http-get nip json
    [ "status" of "completed" = ] filter
    [
        [ "home_team" of ] [ "away_team" of ] bi
        [ [ "country" of ] [ "goals" of ] bi ] bi@
        "%s %s x %s %s\n" printf
    ] each ;

And if you run it, you’ll get something like this:

IN: scratchpad worldcup.
Brazil 3 x Croatia 1
Mexico 1 x Cameroon 0
Spain 1 x Netherlands 5
Chile 3 x Australia 1
Colombia 3 x Greece 0
Ivory Coast 2 x Japan 1
Uruguay 1 x Costa Rica 3
England 1 x Italy 2
Switzerland 2 x Ecuador 1
France 3 x Honduras 0
Argentina 2 x Bosnia and Herzegovina 1
Iran 0 x Nigeria 0
Germany 4 x Portugal 0
Ghana 1 x USA 2
Belgium 2 x Algeria 1
Russia 1 x Korea Republic 1
Brazil 0 x Mexico 0
Cameroon 0 x Croatia 4
Spain 0 x Chile 2
Australia 2 x Netherlands 3
Colombia 2 x Ivory Coast 1
Japan 0 x Greece 0
Uruguay 2 x England 1
Italy 0 x Costa Rica 1
Switzerland 2 x France 5
Honduras 1 x Ecuador 2
Argentina 1 x Iran 0
Nigeria 1 x Bosnia and Herzegovina 0
Germany 2 x Ghana 2

Extra Credit

If we wanted to engineer this a bit more, we could start adding to the example.

First, we could define a tuple class to hold the result of each game. This isn’t really necessary, but it can be nice to see all the fields that are available, and to represent it as an object rather than just a hashtable:

TUPLE: game home_team home_team_events home_team_tbd
away_team away_team_events away_team_tbd winner match_number
datetime location status ;

Then we could get all the game results as tuples, using from-slots to convert from an array of hashtable of attributes:

: worldcup ( -- games )
    "https://worldcup.sfg.io/matches" http-get nip json
    [ game from-slots ] map ;

Next, having fun with colors, we use character styles to print the winner in bold green text.

CONSTANT: winner-style H{
    { foreground COLOR: MediumSeaGreen }
    { font-style bold }
}

And then, using more code than is probably necessary, we print out each team, making sure to format the winner using the style we just defined (using locals for convenience):

: game. ( game -- )
    [let
        [ home_team>> ] [ away_team>> ] [ winner>> ] tri
            :> ( home away winner )

        home "country" of dup winner =
        [ winner-style format ] [ write ] if bl
        home "goals" of number>string write

        " x " write

        away "country" of dup winner =
        [ winner-style format ] [ write ] if bl
        away "goals" of number>string write nl
    ] ;

We want to see the completed games, so we can make a word to filter the list of games.

: completed-games ( games -- games' )
    [ status>> "completed" = ] filter ;

Finally, putting all this together, we make one word to print out all the completed games:

: worldcup. ( -- )
    worldcup completed-games [ game. ] each ;

The code for this is on my GitHub.