//testcase {
//    input  "x";
//    output "a1:{x}";
//
//    s   = a        => a1
//    a   = s        => s1
//    a   = ^"x"
//}
//
//testcase {
//    input  "x";
//    output "x";
//    output "s2:{s2:{s0 s0} x}";
//    output "s2:{s0 x}";
//
//
//    s   = s s      => s2
//    s   = ^"x"
//    s   = ()       => s0
//}

testcase {
    input "ab c";
    output "1:{{a b} {c}}";

    s     = ids
    ids   = id (" " ids &~ id ~[]*) => "1"
          | id (    ids &~ id ~[]*) => "2"
          | id
    id    = [a-z]++
}

testcase {
    input "ab c";

    output "2:{{a} 1:{{b} {c}}}";
    output "1:{{a b} {c}}";

    s     = ids
    ids   = id " " ids => "1"
          | id     ids => "2"
          | id
    id    = [a-z]+
}

testcase {
    input "aaabbbccc";
    output "ab";

    s     = ab & dc
    ab    = a b       => ab
    dc    = d c       => dc
    a     = "a" a     | ()
    b     = "b" b "c" | ()
    c     = "c" c     | ()
    d     = "a" d "b" | ()
}

testcase {
    input "aaabbbbccc";

    s     = ab & dc
    ab    = a b       => ab
    dc    = d c       => dc
    a     = "a" a     | ()
    b     = "b" b "c" | ()
    c     = "c" c     | ()
    d     = "a" d "b" | ()
}

testcase {
    input "aabb";
    output "xbx:{{a} abab:{a b} {b}}";

    x     = ~[]
    s     = x* b x* => xbx
    b     = [ab][ab] => abab
         &~ ( "aa" | "bb" )
}

testcase {
    input "12111211";
    output "ac:{{2 1 2 1}}";
    //output "a:{{2 1 2 1}}";
    //output "c:{{c:{1 1} c:{1 1}}}";

    s   = ab => "ab"
        | ac => "ac"
        | bc => "bc"
        //| a  =>  "a"
        //| b  =>  "b"
        //| c  =>  "c"
    ab   = a & b
    ac   = a & c
    bc   = b & c
    a   = ("1" x)*
    b   = (x "2" => "b")*
    c   = (x "2" x "1" => "c")*
    x   = [123]
}

testcase {
    input  "qxbambambam";
    output "bam:{a bam:{a bam:{a x:{x}}}}";

    s   = "q" z
    z   = a z ^"bam"
    z   = ^"x"
    a   = ()       => "a"
}

testcase {
    input  "baaaa";
    output "s2:{b0 a:{a:{epsilon}}}";
    output "b:{a:{a:{epsilon}} epsilon}";
    s   = b t        => "s2"
        | ^"b" t b
    t   = ^"a" t "a"
        | ()         => "epsilon"
    b   = "b"        => "b0"
        | ()         => "epsilon"
}

testcase {
    input  "qaq";
    output "q:{a:{s1:{epsilon}}}";

    s   = ^"q" x "q"
    x   = ^"a" a
    x   = ()        => "epsilon"
    a   = x         => "s1"
}

testcase {
    input "baa";
    output "s1:{a2:{a2:{a0 b0} b0}}";

    s   = "b" a     => "s1"
    a   = "a" a b   => "a2"
        | ()        => "a0"
    b   = ()        => "b0"
}

testcase {
    input  "aaa";

    output "s3:{s3:{epsilon a0 epsilon epsilon} epsilon epsilon epsilon}";
    output "s3:{s3:{epsilon epsilon epsilon epsilon} a0 epsilon epsilon}";
    output "s3:{s3:{epsilon epsilon a0 epsilon} epsilon epsilon epsilon}";
    output "s3:{s3:{epsilon epsilon epsilon a0} epsilon epsilon epsilon}";
    output "s3:{epsilon epsilon a0 a0}";
    output "s3:{s3:{s3:{epsilon epsilon epsilon epsilon} epsilon epsilon epsilon} epsilon epsilon epsilon}";
    output "s3:{s3:{epsilon epsilon epsilon epsilon} epsilon epsilon a0}";
    output "s3:{s3:{epsilon epsilon epsilon epsilon} epsilon a0 epsilon}";
    output "s3:{epsilon a0 epsilon a0}";
    output "s3:{epsilon a0 a0 epsilon}";

    s   = "a" s a a a => "s3"
        | ()          => "epsilon"
    a   = "a"         => "a0"
        | ()          => "epsilon"
}

testcase {
    input "aa";
    output "poo:{poo:{poox poox} poox}";
    output "poo:{poox poo:{poox poox}}";
    s   = s s "a"  => "poo"
        | ()       => "poox"
}

testcase {
    input "baa";
    output "s:{aa:{aa:{a b} b}}";
    s   = "b" a      => "s"
    a   = "a" a b    => "aa"
    a   = ()         => "a"
    b   = ()         => "b"
}

testcase {
    input "aaab";
    output "sx:{b aa:{aa:{b b} b}}";
    s   = b d "a" "b"  => "sx"
    s   = "a" d "a" d  => "sy"
    d   = "a" a b      => "aa"
    a   = "a" b b      => "aa"
    a   = ()           => "a"
    b   = ()           => "b"
}

testcase {
    input "a+(b*c)";
    output "+:{{a} *:{{b} {c}}}";

    s     = r
    r     = id
          | r ^"*" r
          | r ^"+" r
          | "(" r ")"
    id    = [a-z]++
}

testcase {
    input "a+b-d*c";
    output "plus:{stringify:{{a}} minus:{stringify:{{b}} times:{stringify:{{d}} stringify:{{c}}}}}";
    output "times:{plus:{stringify:{{a}} minus:{stringify:{{b}} stringify:{{d}}}} stringify:{{c}}}";
    output "plus:{stringify:{{a}} times:{minus:{stringify:{{b}} stringify:{{d}}} stringify:{{c}}}}";
    output "times:{minus:{plus:{stringify:{{a}} stringify:{{b}}} stringify:{{d}}} stringify:{{c}}}";
    output "minus:{plus:{stringify:{{a}} stringify:{{b}}} times:{stringify:{{d}} stringify:{{c}}}}";
    w    = " "
    l    = id
    s    = l "=" q  => "assign"
         | q
    q    = id
         | l "=" q       => "assign"
         | q "-" q       => "minus"
         | q "+" q       => "plus"
         | q "*" q       => "times"
         | "(" q ")"
    id     = idl++       => "stringify"
    idl    = [a-d]
}

//testcase {
//    input "a*b*c";
//    output "times:{stringify:{{a}} times:{stringify:{{b}} stringify:{{c}}}}";
//    w    = " "
//    l    = id
//    s    = l "=" r  => "assign"
//         | r
//    r    = l
//         | l "=" r       => "assign"
//         | r "+" r       => "plus"
//         | (r) "*" r       => "times"
//         | "(" r ")"
//         | r r           => "times"
//    id     = idl++       => "stringify"
//    idl    = [a-d]
//}

testcase {
    input "a+b*c";
    output "plus:{stringify:{{a}} times:{stringify:{{b}} stringify:{{c}}}}";
    w    = " "
    l    = id
    s    = l "=" r  => "assign"
         | r
    r    = l
         | l "=" r       => "assign"
         | r "+" r       => "plus"
         > r "*" r       => "times"
         | "(" r ")"
         | r r           => "times"
    id     = idl++       => "stringify"
    idl    = [a-d]
}

testcase {
  input "aa bb";
  output "{q:{{a a}} q:{{b b}}}";

  s    = q */ ws
  ws   = " "*
  q    = [a-z]++ => "q"
}

//testcase {
//
//    input "
//
//
//
// while x>0
//    while y>0
//       foo()
//          bar()
//
//
// while x>0
//    while y>0
//          foo()
//        bar()
//
//
//
//";
//  output "smt:{while:{>:{{x} {0}} while:{>:{{y} {0}} sbb:{{f o o} {b a r}}}} while:{>:{{x} {0}} sbb:{while:{>:{{y} {0}} {f o o}} {b a r}}}}";
//
//indent  !  = ww
//outdent !  = " "  outdent " "
//           | " "  (~[]*)  "\n"
//
//w        !  = " " | "\n" | "\r"
//ws       !  = w*
//ww       !  = sp*
//sp       !  = " "
//any      !  = ~[]*
//
//s           = ws statement ws statement ws => smt
//
//block       = "\n" indent  blockBody
//           &~ "\n" outdent ~[\ ] ~[]*
//
//blockBody   = statement
//            > statement ws blockBody => "sbb"
//
//statement   = call
//            | ^"while" expr block /ws
//
//expr        = ident
//            | call
//            | expr ^">" expr   /ws
//            | num
//
//call        = expr "()"        /ws
//
//num         = [0-9]++
//
//ident       = [a-z]++ &~ keyword
//keyword     = "if" | "then" | "else" | "while"
//
//
//
//}
//


testcase {
    input "abc                         ";

    s     = q " "* => s
    q     = [a-z] [a-z] [a-z] => a3
         &~ ~[] "b" ~[]*
}

testcase {
    input "abc                         ";
    output "s:{a b c}";

    s     = [a-z] [a-z] [a-z] " "* => s
}

testcase {

    input "a+2";
    output "";

    s       = Expr
    Expr    = [0-9]++
            | Plus:: left:Expra "+" right:Expr
    Expra   = Foo:: ("a" | "b")

}