// Comparing against bottom is not officially supported by the spec.
// In practice it is used for a variety of purposes.
//
// TODO: It should really be replaced with two builtins:
//
//    - exists(reference): check if a certain field exists.
//    - isvalid(value):    check if a certain value is valid (recursively).
//
// For now it implements something in between these two: it fails if a value
// resolves to an error, but not necessarily if it does so recursively.
// Although adding a recursive check is easy, it will break existing
// configurations, as a recursive evaluation will trigger cycles where these
// are perhaps not expected.

// To verify these tests, each result should have a field
//
//     X: "user@example.com"
//
// for the large and medium examples and
//
//     X: "message: hello"
//
// for the simple example.
//
// These are not automatically tested using CUE to avoid interfering with the
// evaluation.

-- in.cue --
import (
	"strconv"
	"regexp"
)

simple: {
    #message: #"^(message: (?P<message>.*))?$"#


    p1: {
        X: "message: hello"
        #aux: {
            if Y.message == _|_ {
                message: ""
            }
            if Y.message != _|_ {
                message: "message: " + Y.message
            }
        }

        Y: regexp.FindNamedSubmatch(#message, X)
        X: #aux.message
    }

    p2: {
        #aux: {
            if Y.message == _|_ {
                message: ""
            }
            if Y.message != _|_ {
                message: "message: " + Y.message
            }
        }

        X: "message: hello"
        Y: regexp.FindNamedSubmatch(#message, X)
        X: #aux.message
    }

    p3: {
        #aux: {
            if Y.message == _|_ {
                message: ""
            }
            if Y.message != _|_ {
                message: "message: " + Y.message
            }
        }

        Y: regexp.FindNamedSubmatch(#message, X)
        X: #aux.message
        X: "message: hello"
    }
}

medium: {
    #userHostPort: #"^((?P<userinfo>[[:alnum:]]*)@)?(?P<host>[[:alnum:].]+)$"#

    p1: {
        Y: {
            userinfo: "user"
            host: "example.com"
        }

        X: #X.userinfo + #X.host

        #X: {
            if Y.userinfo == _|_ {
                userinfo: ""
            }
            if Y.userinfo != _|_ {
                userinfo: Y.userinfo + "@"
            }

            host: Y.host
        }

        Y: {
            if #Y.userinfo != _|_ {
                userinfo: #Y.userinfo + "v"
            }

            host: #Y.host
        }

        #Y: regexp.FindNamedSubmatch(#userHostPort, X)
    }

    p2: {
        X: #X.userinfo + #X.host

        Y: {
            userinfo: "user"
            host: "example.com"
        }

        #X: {
            if Y.userinfo == _|_ {
                userinfo: ""
            }
            if Y.userinfo != _|_ {
                userinfo: Y.userinfo + "@"
            }

            host: Y.host
        }

        Y: {
            if #Y.userinfo != _|_ {
                userinfo: #Y.userinfo + "v"
            }

            host: #Y.host
        }

        #Y: regexp.FindNamedSubmatch(#userHostPort, X)
    }

    p3: {
        X: #X.userinfo + #X.host

        #X: {
            if Y.userinfo == _|_ {
                userinfo: ""
            }
            if Y.userinfo != _|_ {
                userinfo: Y.userinfo + "@"
            }

            host: Y.host
        }

        Y: {
            userinfo: "user"
            host: "example.com"
        }

        Y: {
            if #Y.userinfo != _|_ {
                userinfo: #Y.userinfo + "v"
            }

            host: #Y.host
        }

        #Y: regexp.FindNamedSubmatch(#userHostPort, X)
    }

    p4: {
        X: #X.userinfo + #X.host

        #X: {
            if Y.userinfo == _|_ {
                userinfo: ""
            }
            if Y.userinfo != _|_ {
                userinfo: Y.userinfo + "@"
            }

            host: Y.host
        }

        Y: {
            if #Y.userinfo != _|_ {
                userinfo: #Y.userinfo + "v"
            }

            host: #Y.host
        }

        #Y: regexp.FindNamedSubmatch(#userHostPort, X)

        Y: {
            userinfo: "user"
            host: "example.com"
        }
    }
}

large: {
    #userHostPort: 	#"^((?P<userinfo>[[:alnum:]]*)@)?(?P<host>[[:alnum:].]+)(:(?P<port>\d+))?$"#

    p1: {
        Y: {
            userinfo: "user"
            host:     "example.com"
        }

        X: #X.userinfo + #X.host + #X.port

        #X: {
            if Y.userinfo == _|_ {
                userinfo: ""
            }
            if Y.userinfo != _|_ {
                userinfo: Y.userinfo + "@"
            }

            host: Y.host

            if Y.port == _|_ {
                port: ""
            }
            if Y.port != _|_ {
                port: ":" + strconv.FormatInt(Y.port, 10)
            }
        }

        Y: {
            if #Y.userinfo != _|_ {
                userinfo: #Y.userinfo
            }
            
            host: #Y.host

            if #Y.port != _|_ {
                port: strconv.Atoi(#Y.port)
            }
        }

        #Y: regexp.FindNamedSubmatch(#userHostPort, X)
    }

    p2: {
        X: #X.userinfo + #X.host + #X.port

        Y: {
            userinfo: "user"
            host:     "example.com"
        }

        #X: {
            if Y.userinfo == _|_ {
                userinfo: ""
            }
            if Y.userinfo != _|_ {
                userinfo: Y.userinfo + "@"
            }

            host: Y.host

            if Y.port == _|_ {
                port: ""
            }
            if Y.port != _|_ {
                port: ":" + strconv.FormatInt(Y.port, 10)
            }
        }

        Y: {
            if #Y.userinfo != _|_ {
                userinfo: #Y.userinfo
            }
            
            host: #Y.host

            if #Y.port != _|_ {
                port: strconv.Atoi(#Y.port)
            }
        }

        #Y: regexp.FindNamedSubmatch(#userHostPort, X)
    }

    p3: {
        X: #X.userinfo + #X.host + #X.port

        #X: {
            if Y.userinfo == _|_ {
                userinfo: ""
            }
            if Y.userinfo != _|_ {
                userinfo: Y.userinfo + "@"
            }

            host: Y.host

            if Y.port == _|_ {
                port: ""
            }
            if Y.port != _|_ {
                port: ":" + strconv.FormatInt(Y.port, 10)
            }
        }

        Y: {
            userinfo: "user"
            host:     "example.com"
        }

        Y: {
            if #Y.userinfo != _|_ {
                userinfo: #Y.userinfo
            }
            
            host: #Y.host

            if #Y.port != _|_ {
                port: strconv.Atoi(#Y.port)
            }
        }

        #Y: regexp.FindNamedSubmatch(#userHostPort, X)
    }

    p4: {
        X: #X.userinfo + #X.host + #X.port

        #X: {
            if Y.userinfo == _|_ {
                userinfo: ""
            }
            if Y.userinfo != _|_ {
                userinfo: Y.userinfo + "@"
            }

            host: Y.host

            if Y.port == _|_ {
                port: ""
            }
            if Y.port != _|_ {
                port: ":" + strconv.FormatInt(Y.port, 10)
            }
        }

        #Y: regexp.FindNamedSubmatch(#userHostPort, X)

        Y: {
            userinfo: "user"
            host:     "example.com"
        }

        Y: {
            if #Y.userinfo != _|_ {
                userinfo: #Y.userinfo
            }

            host: #Y.host

            if #Y.port != _|_ {
                port: strconv.Atoi(#Y.port)
            }
        }
    }
}
-- out/eval --
(struct){
  simple: (struct){
    #message: (string){ "^(message: (?P<message>.*))?$" }
    p1: (struct){
      X: (string){ "message: hello" }
      #aux: (#struct){
        message: (string){ "message: hello" }
      }
      Y: (struct){
        message: (string){ "hello" }
      }
    }
    p2: (struct){
      #aux: (#struct){
        message: (string){ "message: hello" }
      }
      X: (string){ "message: hello" }
      Y: (struct){
        message: (string){ "hello" }
      }
    }
    p3: (struct){
      #aux: (#struct){
        message: (string){ "message: hello" }
      }
      Y: (struct){
        message: (string){ "hello" }
      }
      X: (string){ "message: hello" }
    }
  }
  medium: (struct){
    #userHostPort: (string){ "^((?P<userinfo>[[:alnum:]]*)@)?(?P<host>[[:alnum:].]+)$" }
    p1: (struct){
      Y: (struct){
        userinfo: (string){ "user" }
        host: (string){ "example.com" }
      }
      X: (string){ "user@example.com" }
      #X: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user@" }
      }
      #Y: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user" }
      }
    }
    p2: (struct){
      X: (string){ "user@example.com" }
      Y: (struct){
        userinfo: (string){ "user" }
        host: (string){ "example.com" }
      }
      #X: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user@" }
      }
      #Y: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user" }
      }
    }
    p3: (struct){
      X: (string){ "user@example.com" }
      #X: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user@" }
      }
      Y: (struct){
        userinfo: (string){ "user" }
        host: (string){ "example.com" }
      }
      #Y: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user" }
      }
    }
    p4: (struct){
      X: (string){ "user@example.com" }
      #X: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user@" }
      }
      Y: (struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user" }
      }
      #Y: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user" }
      }
    }
  }
  large: (struct){
    #userHostPort: (string){ "^((?P<userinfo>[[:alnum:]]*)@)?(?P<host>[[:alnum:].]+)(:(?P<port>\\d+))?$" }
    p1: (struct){
      Y: (struct){
        userinfo: (string){ "user" }
        host: (string){ "example.com" }
      }
      X: (string){ "user@example.com" }
      #X: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user@" }
        port: (string){ "" }
      }
      #Y: (#struct){
        host: (string){ "example.com" }
        port: (string){ "" }
        userinfo: (string){ "user" }
      }
    }
    p2: (struct){
      X: (string){ "user@example.com" }
      Y: (struct){
        userinfo: (string){ "user" }
        host: (string){ "example.com" }
      }
      #X: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user@" }
        port: (string){ "" }
      }
      #Y: (#struct){
        host: (string){ "example.com" }
        port: (string){ "" }
        userinfo: (string){ "user" }
      }
    }
    p3: (struct){
      X: (string){ "user@example.com" }
      #X: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user@" }
        port: (string){ "" }
      }
      Y: (struct){
        userinfo: (string){ "user" }
        host: (string){ "example.com" }
      }
      #Y: (#struct){
        host: (string){ "example.com" }
        port: (string){ "" }
        userinfo: (string){ "user" }
      }
    }
    p4: (struct){
      X: (string){ "user@example.com" }
      #X: (#struct){
        host: (string){ "example.com" }
        userinfo: (string){ "user@" }
        port: (string){ "" }
      }
      #Y: (#struct){
        host: (string){ "example.com" }
        port: (string){ "" }
        userinfo: (string){ "user" }
      }
      Y: (struct){
        userinfo: (string){ "user" }
        host: (string){ "example.com" }
      }
    }
  }
}
-- out/compile --
--- in.cue
{
  simple: {
    #message: "^(message: (?P<message>.*))?$"
    p1: {
      X: "message: hello"
      #aux: {
        if (〈1;Y〉.message == _|_(explicit error (_|_ literal) in source)) {
          message: ""
        }
        if (〈1;Y〉.message != _|_(explicit error (_|_ literal) in source)) {
          message: ("message: " + 〈2;Y〉.message)
        }
      }
      Y: 〈import;regexp〉.FindNamedSubmatch(〈1;#message〉, 〈0;X〉)
      X: 〈0;#aux〉.message
    }
    p2: {
      #aux: {
        if (〈1;Y〉.message == _|_(explicit error (_|_ literal) in source)) {
          message: ""
        }
        if (〈1;Y〉.message != _|_(explicit error (_|_ literal) in source)) {
          message: ("message: " + 〈2;Y〉.message)
        }
      }
      X: "message: hello"
      Y: 〈import;regexp〉.FindNamedSubmatch(〈1;#message〉, 〈0;X〉)
      X: 〈0;#aux〉.message
    }
    p3: {
      #aux: {
        if (〈1;Y〉.message == _|_(explicit error (_|_ literal) in source)) {
          message: ""
        }
        if (〈1;Y〉.message != _|_(explicit error (_|_ literal) in source)) {
          message: ("message: " + 〈2;Y〉.message)
        }
      }
      Y: 〈import;regexp〉.FindNamedSubmatch(〈1;#message〉, 〈0;X〉)
      X: 〈0;#aux〉.message
      X: "message: hello"
    }
  }
  medium: {
    #userHostPort: "^((?P<userinfo>[[:alnum:]]*)@)?(?P<host>[[:alnum:].]+)$"
    p1: {
      Y: {
        userinfo: "user"
        host: "example.com"
      }
      X: (〈0;#X〉.userinfo + 〈0;#X〉.host)
      #X: {
        if (〈1;Y〉.userinfo == _|_(explicit error (_|_ literal) in source)) {
          userinfo: ""
        }
        if (〈1;Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;Y〉.userinfo + "@")
        }
        host: 〈1;Y〉.host
      }
      Y: {
        if (〈1;#Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;#Y〉.userinfo + "v")
        }
        host: 〈1;#Y〉.host
      }
      #Y: 〈import;regexp〉.FindNamedSubmatch(〈1;#userHostPort〉, 〈0;X〉)
    }
    p2: {
      X: (〈0;#X〉.userinfo + 〈0;#X〉.host)
      Y: {
        userinfo: "user"
        host: "example.com"
      }
      #X: {
        if (〈1;Y〉.userinfo == _|_(explicit error (_|_ literal) in source)) {
          userinfo: ""
        }
        if (〈1;Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;Y〉.userinfo + "@")
        }
        host: 〈1;Y〉.host
      }
      Y: {
        if (〈1;#Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;#Y〉.userinfo + "v")
        }
        host: 〈1;#Y〉.host
      }
      #Y: 〈import;regexp〉.FindNamedSubmatch(〈1;#userHostPort〉, 〈0;X〉)
    }
    p3: {
      X: (〈0;#X〉.userinfo + 〈0;#X〉.host)
      #X: {
        if (〈1;Y〉.userinfo == _|_(explicit error (_|_ literal) in source)) {
          userinfo: ""
        }
        if (〈1;Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;Y〉.userinfo + "@")
        }
        host: 〈1;Y〉.host
      }
      Y: {
        userinfo: "user"
        host: "example.com"
      }
      Y: {
        if (〈1;#Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;#Y〉.userinfo + "v")
        }
        host: 〈1;#Y〉.host
      }
      #Y: 〈import;regexp〉.FindNamedSubmatch(〈1;#userHostPort〉, 〈0;X〉)
    }
    p4: {
      X: (〈0;#X〉.userinfo + 〈0;#X〉.host)
      #X: {
        if (〈1;Y〉.userinfo == _|_(explicit error (_|_ literal) in source)) {
          userinfo: ""
        }
        if (〈1;Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;Y〉.userinfo + "@")
        }
        host: 〈1;Y〉.host
      }
      Y: {
        if (〈1;#Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;#Y〉.userinfo + "v")
        }
        host: 〈1;#Y〉.host
      }
      #Y: 〈import;regexp〉.FindNamedSubmatch(〈1;#userHostPort〉, 〈0;X〉)
      Y: {
        userinfo: "user"
        host: "example.com"
      }
    }
  }
  large: {
    #userHostPort: "^((?P<userinfo>[[:alnum:]]*)@)?(?P<host>[[:alnum:].]+)(:(?P<port>\\d+))?$"
    p1: {
      Y: {
        userinfo: "user"
        host: "example.com"
      }
      X: ((〈0;#X〉.userinfo + 〈0;#X〉.host) + 〈0;#X〉.port)
      #X: {
        if (〈1;Y〉.userinfo == _|_(explicit error (_|_ literal) in source)) {
          userinfo: ""
        }
        if (〈1;Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;Y〉.userinfo + "@")
        }
        host: 〈1;Y〉.host
        if (〈1;Y〉.port == _|_(explicit error (_|_ literal) in source)) {
          port: ""
        }
        if (〈1;Y〉.port != _|_(explicit error (_|_ literal) in source)) {
          port: (":" + 〈import;strconv〉.FormatInt(〈2;Y〉.port, 10))
        }
      }
      Y: {
        if (〈1;#Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: 〈2;#Y〉.userinfo
        }
        host: 〈1;#Y〉.host
        if (〈1;#Y〉.port != _|_(explicit error (_|_ literal) in source)) {
          port: 〈import;strconv〉.Atoi(〈2;#Y〉.port)
        }
      }
      #Y: 〈import;regexp〉.FindNamedSubmatch(〈1;#userHostPort〉, 〈0;X〉)
    }
    p2: {
      X: ((〈0;#X〉.userinfo + 〈0;#X〉.host) + 〈0;#X〉.port)
      Y: {
        userinfo: "user"
        host: "example.com"
      }
      #X: {
        if (〈1;Y〉.userinfo == _|_(explicit error (_|_ literal) in source)) {
          userinfo: ""
        }
        if (〈1;Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;Y〉.userinfo + "@")
        }
        host: 〈1;Y〉.host
        if (〈1;Y〉.port == _|_(explicit error (_|_ literal) in source)) {
          port: ""
        }
        if (〈1;Y〉.port != _|_(explicit error (_|_ literal) in source)) {
          port: (":" + 〈import;strconv〉.FormatInt(〈2;Y〉.port, 10))
        }
      }
      Y: {
        if (〈1;#Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: 〈2;#Y〉.userinfo
        }
        host: 〈1;#Y〉.host
        if (〈1;#Y〉.port != _|_(explicit error (_|_ literal) in source)) {
          port: 〈import;strconv〉.Atoi(〈2;#Y〉.port)
        }
      }
      #Y: 〈import;regexp〉.FindNamedSubmatch(〈1;#userHostPort〉, 〈0;X〉)
    }
    p3: {
      X: ((〈0;#X〉.userinfo + 〈0;#X〉.host) + 〈0;#X〉.port)
      #X: {
        if (〈1;Y〉.userinfo == _|_(explicit error (_|_ literal) in source)) {
          userinfo: ""
        }
        if (〈1;Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;Y〉.userinfo + "@")
        }
        host: 〈1;Y〉.host
        if (〈1;Y〉.port == _|_(explicit error (_|_ literal) in source)) {
          port: ""
        }
        if (〈1;Y〉.port != _|_(explicit error (_|_ literal) in source)) {
          port: (":" + 〈import;strconv〉.FormatInt(〈2;Y〉.port, 10))
        }
      }
      Y: {
        userinfo: "user"
        host: "example.com"
      }
      Y: {
        if (〈1;#Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: 〈2;#Y〉.userinfo
        }
        host: 〈1;#Y〉.host
        if (〈1;#Y〉.port != _|_(explicit error (_|_ literal) in source)) {
          port: 〈import;strconv〉.Atoi(〈2;#Y〉.port)
        }
      }
      #Y: 〈import;regexp〉.FindNamedSubmatch(〈1;#userHostPort〉, 〈0;X〉)
    }
    p4: {
      X: ((〈0;#X〉.userinfo + 〈0;#X〉.host) + 〈0;#X〉.port)
      #X: {
        if (〈1;Y〉.userinfo == _|_(explicit error (_|_ literal) in source)) {
          userinfo: ""
        }
        if (〈1;Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: (〈2;Y〉.userinfo + "@")
        }
        host: 〈1;Y〉.host
        if (〈1;Y〉.port == _|_(explicit error (_|_ literal) in source)) {
          port: ""
        }
        if (〈1;Y〉.port != _|_(explicit error (_|_ literal) in source)) {
          port: (":" + 〈import;strconv〉.FormatInt(〈2;Y〉.port, 10))
        }
      }
      #Y: 〈import;regexp〉.FindNamedSubmatch(〈1;#userHostPort〉, 〈0;X〉)
      Y: {
        userinfo: "user"
        host: "example.com"
      }
      Y: {
        if (〈1;#Y〉.userinfo != _|_(explicit error (_|_ literal) in source)) {
          userinfo: 〈2;#Y〉.userinfo
        }
        host: 〈1;#Y〉.host
        if (〈1;#Y〉.port != _|_(explicit error (_|_ literal) in source)) {
          port: 〈import;strconv〉.Atoi(〈2;#Y〉.port)
        }
      }
    }
  }
}