code: function booleanF(bindings){
  		var value = valueExpr(bindings)
  		value = !!value
  		//if(rel.params[1].params[0].value === true && rel.params[1].params[1].was && rel.params[1].params[1].was.view === 'list') console.log('switch value: ' + value)//+ ' ' + JSON.stringify(rel.params[2]))//.params[0].view)
  		for(var i=0;i<caseValues.length;++i){
  			var cv = caseValues[i]
  			if(cv === value){
  				var res = caseExprs[i](bindings)
  				//if(rel.params[1].params[0].value === true && rel.params[1].params[1].was && rel.params[1].params[1].was.view === 'list') console.log('case result: ' + value + ' -> ' + JSON.stringify(res))
  				return res
  			}
  		}
  		if(defaultExpr){
  			var res = defaultExpr(bindings)
  			//if(rel.params[1].params[0].value === true && rel.params[1].params[1].was && rel.params[1].params[1].was.view === 'list') console.log('default result: ' + value + ' -> ' + JSON.stringify(res))
  			return res
  		}else{
  			console.log('WARNING: no case matched and no default case provided')
  		}
  	}
docs: if(valueExpr.isBoolean) _.errout('test: ' + valueExpr.isBoolean)