--- URI.extract(str[, schemes])
--- URI.extract(str[, schemes]) {|uri_str| ... }

#    ʸ str  URI(ʸ) Фơ֤ޤ
#    ֥åͿȤФURI(ʸ)Ȥ˥֥å¹Ԥ
#    ޤ

#     schemes Ϳϳ륹URI
#    Фޤ

    ʸ str Фƥѥޥå󥰤ߡ
    URI˥ޥåʬʸ󤫤ʤȤ֤ޤ
    Ф URI ʤ nil ֤ޤ

    2ʹߤʸ schemes Ϳ줿
    Υ򸡺ޤ

    ֥åͿ줿 String#scan Ʊͤǡ
    ޥåʬߤĤ뤿Ӥ uri_str 
    ʬƥ֥åɾޤ
    ΤȤͤ nil Ǥ

        # Ĥޤ󥵥ץ
        require 'uri'
        str = "
                http://www.ruby-lang.org/
                http://www.ruby-lang.org/man-1.6/
        "
        p URI.extract(str, %w(http))
        => ["http://www.ruby-lang.org/", "http://www.ruby-lang.org/man-1.6/"]

