'use strict'
/*
* Method
*
* Methods are added, conceptually, to Genfuns, not to objects
* themselves, although the Genfun object does not have any pointers to
* method objects.
*
* The _rank vector is an internal datastructure used during dispatch
* to figure out whether a method is applicable, and if so, how to
* order multiple discovered methods.
*
* Right now, the score method on Method does not take into account any
* ordering, and all arguments to a method are ranked equally for the
* sake of ordering.
*
*/
const Role = require('./role')
const util = require('./util')
module.exports = Method
function Method (genfun, selector, func) {
var method = this
method.genfun = genfun
method.func = func
method._rank = []
method.minimalSelector = 0
const tmpSelector = selector.length ? selector : [Object.prototype]
for (var object, i = tmpSelector.length - 1; i >= 0; i--) {
object = Object.hasOwnProperty.call(tmpSelector, i)
? tmpSelector[i]
: Object.prototype
object = util.dispatchableObject(object)
if (
typeof object === 'function' &&
!object.isGenfun
) {
object = object.prototype
}
if (i > 0 &&
!method.minimalSelector &&
util.isObjectProto(object)) {
continue
} else {
method.minimalSelector++
if (!Object.hasOwnProperty.call(object, Role.roleKeyName)) {
// Object.defineProperty is JS 1.8.0+
Object.defineProperty(
object, Role.roleKeyName, {value: [], enumerable: false})
}
// XXX HACK - no method replacement now, so we just shove
// it in a place where it'll always show up first. This
// would probably seriously break method combination if we
// had it.
object[Role.roleKeyName].unshift(new Role(method, i))
}
}
}
Method.setRankHierarchyPosition = (method, index, hierarchyPosition) => {
method._rank[index] = hierarchyPosition
}
Method.clearRank = method => {
method._rank = []
}
Method.isFullySpecified = method => {
for (var i = 0; i < method.minimalSelector; i++) {
if (!method._rank.hasOwnProperty(i)) {
return false
}
}
return true
}
Method.score = method => {
// TODO - this makes all items in the list equal
return method._rank.reduce((a, b) => a + b, 0)
}
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