# Copyright 2003 Chris Hibbert under the terms of the MIT license
# found at http://www.opensource.org/licenses/mit-license.html

# Chris Hibbert can be reached at copyright@mydruthers.com

// upcoming:
// def EList := <type:org.erights.e.elib.tables.EList>
def EList := <import:org.erights.e.elib.tables.EList>.asType()

/******************************************************************************
Description of an issue in a market.  Includes a list of positions on the
issue.  Provides a representation for subsets of the positions, which allows
participants to make assumptions about the values assigned to each position.<p>
******************************************************************************/
def makeIssueDescription(desc :Twine, pos :EList) :any {
    require(pos.size() > 1, "must be at least two positions in an issue.")
    def positions := pos.snapshot()

    def issueDescription {
        to desc()         :Twine   { desc }
        to indexes()      :any     { positions.asMap().domain() }
        to cardinality()  :int     { positions.size() }
        to contains(pos)  :boolean { positions.contains(pos) }
        to indexOf(issue) :int     { positions.lastIndexOf1(issue) }
        to positions()    :EList   { positions.snapshot() }

        to printOn(w :TextWriter) {
            w.print(`Issue("${desc}"${positions})`)
        }
    }
}

? def mID := <import:makeIssueDescription>
> def rain := mID("Rain Tomorrow", [false, true])
> def sprinkler := mID("Sprinkler On", [false, true])
> def weather := mID("Weather", ["clear", "cloudy", "rain", "snow"])