ios - Swift doesn't recognize recursive call to function, thinks it's a local variable -

i following along stanford swift course on itunes. in lesson 3 professor writes recursive function evaluate stack of operators , operands.

here code professor has typed it:

class calculatorbrain {    private enum op {        case operand(double)        case unaryoperation(string, double -> double)        case binaryoperation(string, (double, double) -> double)    }     private var opstack = [op]()     private var knownops = [string:op]()     init() {     knownops["×"] = op.binaryoperation("×", *)     knownops["+"] = op.binaryoperation("+", +)     knownops["-"] = op.binaryoperation("-") { $1 - $0 }     knownops["÷"] = op.binaryoperation("÷") { $1 / $0 }     knownops["√"] = op.unaryoperation("√", sqrt)    }     func pushoperand(operand: double) {       opstack.append(op.operand(operand))    }     func performoperation(symbol: string) {       if let operation = knownops[symbol] {         opstack.append(operation)       }    }     private func evaluate(ops: [op]) -> (result: double?, remainingops: [op])    {     var remainingops = ops     if !remainingops.isempty {         let op = remainingops.removelast()         switch op {         case .operand(let operand):             return (operand, remainingops)         case .unaryoperation(_, let operation):             let operandevaluation = evaluate(remainingops)             if let operand = operandevaluation.result {                 return (operation(operand), operandevaluation.remainingops)             }         case .binaryoperation(_, let operation):         // code snipped         }     }     return (nil, ops)    } } 

i compiler error doesn't.

the error on line let operandevaluation = evaluate(remainingops). error "use of local variable 'evaluate' before declaration"

does know why i'm getting error? it's supposed recursive call function evaluate, instead compiler thinks evaluate local variable.

i using xcode 6.4 on os x 10.10.4

thanks!

really strange error. got error, too.

however fix adding bracket if clause several lines below error.

thanks!