CODEWITHSUNDEEP
swift
krish
krish

Reputation: 159

How to use natural log in Swift?

I am doing a coding project. In this coding project I am constructing a calculator. I wanted to use natural log (ln). But keep getting an error that says Anonymous closure argument not contained in a closure. Here is my code, it is in a struct file:

import Foundation

struct CalculatorBrain{
    private var accumulator: Double?
    private enum Operation{
        case unaryOperation((Double) -> Double)
    }

    private var operations: Dictionary<String,Operation> =
        [
            // Unary Operations 
            "ln" : Operation.unaryOperation(log( $0 )), // this is the line where the error is
            "√" : Operation.unaryOperation(sqrt),
            "cos" : Operation.unaryOperation(cos),
            "sin" : Operation.unaryOperation(sin),
            "tan" : Operation.unaryOperation(tan),
            "sinh" : Operation.unaryOperation(sinh),
            "cosh" : Operation.unaryOperation(cosh),
            "tanh" : Operation.unaryOperation(tanh),
            "%" : Operation.unaryOperation({ $0 / 100 }),
            "±" : Operation.unaryOperation({ -$0 }),
        ]

    mutating func performOperation(_ symbol: String){
        if let operation = operations[symbol]{
            switch operation {
            case .unaryOperation (let function):
                if accumulator != nil{
                    accumulator = function(accumulator!)
                }

Upvotes: 0

Views: 2598

Answers (2)

CRD
CRD

Reputation: 53010

Consider your code, for square root and trig functions you wrote, for example:

"cos" : Operation.unaryOperation(cos)

which just references the function, here cos, by name resulting in a function value. For two others you wrote a closure, for example:

"%" : Operation.unaryOperation({ $0 / 100 })

here you have use a closure ({ ... }) to obtain your function value. Then there is your log line producing an error:

"ln" : Operation.unaryOperation(log( $0 ))

this is neither the first or second case. Did you intend to write a closure, i.e. { log($0) }, or just reference the existing function, i.e. log? Either is valid.

Pick one of the above two options, then get some sleep/coffee ;-)

HTH

Upvotes: 2

Code Different
Code Different

Reputation: 93191

You should not write $0 because there is no closure, just specifying the name of the function is enough:

"ln" : Operation.unaryOperation(log)

Upvotes: 2

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