# Copyright 2005 Kevin Reid, under the terms of the MIT X license
# found at http://www.opensource.org/licenses/mit-license.html ................

pragma.enable("easy-return")
pragma.disable("explicit-result-guard")
pragma.enable("accumulator")

def StructureException := <import:org.cubik.cle.prim.StructureException>
def simplifyFQName := <import:org.cubik.cle.prim.simplifyFQName>

def defineExceptionGuard implements DeepFrozen {
  to run(matchTypeIDs :List[String]) {
    
    def idSet := matchTypeIDs.asSet()

    def exceptionGuard {
      to __printOn(out :TextWriter) {
        var sep := ""
        for x in matchTypeIDs { 
          out.print(sep, simplifyFQName(x))
          sep := "|"
        }
      }
    
      to coerce(specimen, optEjector) {
        def se := StructureException.coerce(specimen, optEjector)
        def type := se.__getAllegedType()
        if (accum false for super in type.getSupers() { _ | idSet.contains(super.getOptFQName()) }) {
          return se
        } else {
          throw.eject(optEjector, `exception $se doesn't match types $matchTypeIDs`)
        }
      }
    }
  
    return exceptionGuard
  }
}