country-codes.ss
(module country-codes mzscheme
  (require (lib "contract.ss")
           (lib "etc.ss")
           (lib "list.ss"))
  
  (provide/contract [country-codes (list-immutableof string?)]
                    [country-code? (string? . -> . boolean?)])
  
  ;; File comes from ISO 3166:
  ;;http://www.iso.org/iso/en/prods-services/iso3166ma/02iso-3166-code-lists/list-en1-semic.txt
  (define iso3166-text #<<EOF
AFGHANISTAN;AF
Ă…LAND ISLANDS;AX
ALBANIA;AL
ALGERIA;DZ
AMERICAN SAMOA;AS
ANDORRA;AD
ANGOLA;AO
ANGUILLA;AI
ANTARCTICA;AQ
ANTIGUA AND BARBUDA;AG
ARGENTINA;AR
ARMENIA;AM
ARUBA;AW
AUSTRALIA;AU
AUSTRIA;AT
AZERBAIJAN;AZ
BAHAMAS;BS
BAHRAIN;BH
BANGLADESH;BD
BARBADOS;BB
BELARUS;BY
BELGIUM;BE
BELIZE;BZ
BENIN;BJ
BERMUDA;BM
BHUTAN;BT
BOLIVIA;BO
BOSNIA AND HERZEGOVINA;BA
BOTSWANA;BW
BOUVET ISLAND;BV
BRAZIL;BR
BRITISH INDIAN OCEAN TERRITORY;IO
BRUNEI DARUSSALAM;BN
BULGARIA;BG
BURKINA FASO;BF
BURUNDI;BI
CAMBODIA;KH
CAMEROON;CM
CANADA;CA
CAPE VERDE;CV
CAYMAN ISLANDS;KY
CENTRAL AFRICAN REPUBLIC;CF
CHAD;TD
CHILE;CL
CHINA;CN
CHRISTMAS ISLAND;CX
COCOS (KEELING) ISLANDS;CC
COLOMBIA;CO
COMOROS;KM
CONGO;CG
CONGO, THE DEMOCRATIC REPUBLIC OF THE;CD
COOK ISLANDS;CK
COSTA RICA;CR
COTE D'IVOIRE;CI
CROATIA;HR
CUBA;CU
CYPRUS;CY
CZECH REPUBLIC;CZ
DENMARK;DK
DJIBOUTI;DJ
DOMINICA;DM
DOMINICAN REPUBLIC;DO
ECUADOR;EC
EGYPT;EG
EL SALVADOR;SV
EQUATORIAL GUINEA;GQ
ERITREA;ER
ESTONIA;EE
ETHIOPIA;ET
FALKLAND ISLANDS (MALVINAS);FK
FAROE ISLANDS;FO
FIJI;FJ
FINLAND;FI
FRANCE;FR
FRENCH GUIANA;GF
FRENCH POLYNESIA;PF
FRENCH SOUTHERN TERRITORIES;TF
GABON;GA
GAMBIA;GM
GEORGIA;GE
GERMANY;DE
GHANA;GH
GIBRALTAR;GI
GREECE;GR
GREENLAND;GL
GRENADA;GD
GUADELOUPE;GP
GUAM;GU
GUATEMALA;GT
GUERNSEY;GG
GUINEA;GN
GUINEA-BISSAU;GW
GUYANA;GY
HAITI;HT
HEARD ISLAND AND MCDONALD ISLANDS;HM
HOLY SEE (VATICAN CITY STATE);VA
HONDURAS;HN
HONG KONG;HK
HUNGARY;HU
ICELAND;IS
INDIA;IN
INDONESIA;ID
IRAN, ISLAMIC REPUBLIC OF;IR
IRAQ;IQ
IRELAND;IE
ISLE OF MAN;IM
ISRAEL;IL
ITALY;IT
JAMAICA;JM
JAPAN;JP
JERSEY;JE
JORDAN;JO
KAZAKHSTAN;KZ
KENYA;KE
KIRIBATI;KI
KOREA, DEMOCRATIC PEOPLE'S REPUBLIC OF;KP
KOREA, REPUBLIC OF;KR
KUWAIT;KW
KYRGYZSTAN;KG
LAO PEOPLE'S DEMOCRATIC REPUBLIC;LA
LATVIA;LV
LEBANON;LB
LESOTHO;LS
LIBERIA;LR
LIBYAN ARAB JAMAHIRIYA;LY
LIECHTENSTEIN;LI
LITHUANIA;LT
LUXEMBOURG;LU
MACAO;MO
MACEDONIA, THE FORMER YUGOSLAV REPUBLIC OF;MK
MADAGASCAR;MG
MALAWI;MW
MALAYSIA;MY
MALDIVES;MV
MALI;ML
MALTA;MT
MARSHALL ISLANDS;MH
MARTINIQUE;MQ
MAURITANIA;MR
MAURITIUS;MU
MAYOTTE;YT
MEXICO;MX
MICRONESIA, FEDERATED STATES OF;FM
MOLDOVA, REPUBLIC OF;MD
MONACO;MC
MONGOLIA;MN
MONTENEGRO;ME
MONTSERRAT;MS
MOROCCO;MA
MOZAMBIQUE;MZ
MYANMAR;MM
NAMIBIA;NA
NAURU;NR
NEPAL;NP
NETHERLANDS;NL
NETHERLANDS ANTILLES;AN
NEW CALEDONIA;NC
NEW ZEALAND;NZ
NICARAGUA;NI
NIGER;NE
NIGERIA;NG
NIUE;NU
NORFOLK ISLAND;NF
NORTHERN MARIANA ISLANDS;MP
NORWAY;NO
OMAN;OM
PAKISTAN;PK
PALAU;PW
PALESTINIAN TERRITORY, OCCUPIED;PS
PANAMA;PA
PAPUA NEW GUINEA;PG
PARAGUAY;PY
PERU;PE
PHILIPPINES;PH
PITCAIRN;PN
POLAND;PL
PORTUGAL;PT
PUERTO RICO;PR
QATAR;QA
REUNION;RE
ROMANIA;RO
RUSSIAN FEDERATION;RU
RWANDA;RW
SAINT HELENA;SH
SAINT KITTS AND NEVIS;KN
SAINT LUCIA;LC
SAINT PIERRE AND MIQUELON;PM
SAINT VINCENT AND THE GRENADINES;VC
SAMOA;WS
SAN MARINO;SM
SAO TOME AND PRINCIPE;ST
SAUDI ARABIA;SA
SENEGAL;SN
SERBIA;RS
SEYCHELLES;SC
SIERRA LEONE;SL
SINGAPORE;SG
SLOVAKIA;SK
SLOVENIA;SI
SOLOMON ISLANDS;SB
SOMALIA;SO
SOUTH AFRICA;ZA
SOUTH GEORGIA AND THE SOUTH SANDWICH ISLANDS;GS
SPAIN;ES
SRI LANKA;LK
SUDAN;SD
SURINAME;SR
SVALBARD AND JAN MAYEN;SJ
SWAZILAND;SZ
SWEDEN;SE
SWITZERLAND;CH
SYRIAN ARAB REPUBLIC;SY
TAIWAN, PROVINCE OF CHINA;TW
TAJIKISTAN;TJ
TANZANIA, UNITED REPUBLIC OF;TZ
THAILAND;TH
TIMOR-LESTE;TL
TOGO;TG
TOKELAU;TK
TONGA;TO
TRINIDAD AND TOBAGO;TT
TUNISIA;TN
TURKEY;TR
TURKMENISTAN;TM
TURKS AND CAICOS ISLANDS;TC
TUVALU;TV
UGANDA;UG
UKRAINE;UA
UNITED ARAB EMIRATES;AE
UNITED KINGDOM;GB
UNITED STATES;US
UNITED STATES MINOR OUTLYING ISLANDS;UM
URUGUAY;UY
UZBEKISTAN;UZ
VANUATU;VU
VENEZUELA;VE
VIET NAM;VN
VIRGIN ISLANDS, BRITISH;VG
VIRGIN ISLANDS, U.S.;VI
WALLIS AND FUTUNA;WF
WESTERN SAHARA;EH
YEMEN;YE
ZAMBIA;ZM
ZIMBABWE;ZW
EOF
    )
  (define ht (make-hash-table 'equal))
  (let loop ([i 0])
    (cond [(regexp-match-positions #rx"([^;\n]+);([A-Z][A-Z])" iso3166-text i)
           =>
           (lambda (matches)
             (let ([country (substring iso3166-text
                                       (car (second matches))
                                       (cdr (second matches)))]
                   [code (substring iso3166-text
                                    (car (third matches))
                                    (cdr (third matches)))])
               (hash-table-put! ht code country)
               (loop (cdr (car matches)))))]))
  
  (define country-codes
    (foldr cons-immutable empty (hash-table-map ht (lambda (k v) k))))
  
  
  (define (lookup a-name)
    (hash-table-get
     ht a-name
     (lambda ()
       (and (= (string-length a-name) 2)
            (hash-table-get ht
                            (string (char-upcase (string-ref a-name 0))
                                    (char-upcase (string-ref a-name 1)))
                            #f)))))
  
  (define (country-code? a-name)
    (and (lookup a-name) #t))
  
  (define (country-code->name a-code)
    (lookup a-code))
  
  (provide/contract [country-code->name (string? . -> . (or/c string? false/c))]))