code: function mapType(rel, ch){
  	var inputType = rel.params[0].schemaType//ch.computeType(rel.params[0], ch.bindingTypes)
  	var singleInputType = inputType.members
  	//console.log('singleInputType: ' + JSON.stringify(singleInputType))
  	//console.log('inputType: ' + JSON.stringify(inputType))
  	_.assertDefined(singleInputType)
  	
  	var implicits1 = rel.params[1].implicits
  	var implicits2 = rel.params[2].implicits
  	
  	var binding1 = {}
  	binding1[implicits1[0]] = singleInputType
  	var binding2 = {}
  	binding2[implicits2[0]] = singleInputType
  	
  	//s.log('map bound key ' + implicits1[1])
  	//s.log('map bound value ' + implicits1[1])
  	
  	var keyType = ch.computeMacroType(rel.params[1], ch.bindingTypes, binding1)
  	var valueType = ch.computeMacroType(rel.params[2], ch.bindingTypes, binding2)
  	if(rel.params.length === 4){
  		var implicits3 = rel.params[3].implicits
  		var moreBinding = {}
  		moreBinding[implicits3[0]] = valueType
  		moreBinding[implicits3[1]] = valueType
  		ch.computeMacroType(rel.params[3], ch.bindingTypes, moreBinding)
  	}
  
  	//console.log('map: ' + JSON.stringify([keyType,valueType]))
  	
  	if(keyType.type === 'set' || keyType.type === 'list'){
  		keyType = keyType.members
  	}
  	
  	_.assert(keyType.type !== 'set')
  	_.assert(keyType.type !== 'list')
  	_.assert(valueType.type !== 'set')
  	_.assert(valueType.type !== 'list')
  	
  
  	return {type: 'map', key: keyType, value: valueType}
  }
docs: var mapSyncOptimization = require('./map_sync_optimization')