Swift: Spreadsheet Row Sorting

gistfile1.txt

import UIKit


enum Field:Comparable {
    case Number(Double)
    case Str(String)
    func num() -> Double? {
        switch self {
        case .Number(let num):
            return num
        default:
            return nil
        }
    }
    func str() -> String? {
        switch self {
        case .Str(let str):
            return str
        default:
            return nil
        }
    }
    
}

func ==(x: Field, y: Field) -> Bool {
    if let n1 = x.num(),
        n2 = y.num() {
            return n1 == n2
    }
    else if let s1 = x.str(),
        s2 = y.str() {
            return s1 == s2
    }
    return false
}

func <(x: Field, y: Field) -> Bool {
    if let n1 = x.num(),
        n2 = y.num() {
            return n1 < n2
    }
    else if let s1 = x.str(),
        s2 = y.str() {
            return s1 < s2
    }
    return false

}

var aFieldList = [Field.Str("hello"), Field.Number(12), Field.Str("apple"), Field.Str("pair"), Field.Number(10)]

var sortedStrings = sorted(filter(aFieldList){$0.str() != nil})
var sortedNumbers = sorted(filter(aFieldList){$0.num() != nil})
aFieldList = [sortedStrings,sortedNumbers].flatMap{$0}




struct Column {
    var fields:[Field]
    init(fields:[Field]) {
            self.fields = fields
    }
 
    mutating func sort() {
        let sortedStrings = sorted(filter(fields){$0.str() != nil})
        let sortedNumbers = sorted(filter(fields){$0.num() != nil})
        fields = [sortedStrings,sortedNumbers].flatMap{$0}
        
    }
}



struct Table {
    var columns:[Column]
    init (columns:[Column]) {
        self.columns = columns
    }
    
    private func secondarySorted(arr1:Column, var arr2:Column) -> Column {
        let rows = arr1.fields.reverse().map{(object1:$0, object2:arr2.fields.removeLast())}
        var filteredStrings = rows.filter{$0.object1.str() != nil}
        var filteredNumbers = rows.filter{$0.object1.num() != nil}
        filteredStrings.sort({$0.object1 < $1.object1})
        filteredNumbers.sort({$0.object1 < $1.object1})
        let sortedRows = [filteredStrings,filteredNumbers]
        return Column(fields:sortedRows.flatMap{$0.map{$0.object2}})
    }
    
    mutating func sortColumnsByColumn(ind:Int) {
        let sortingColumn = columns[ind]
        columns = columns.map{self.secondarySorted(sortingColumn,arr2: $0)}
    }

}



let fieldArray1 = [Field.Number(8), Field.Str("pear"), Field.Str("apple"), Field.Str("shoes"), Field.Number(10)]

let fieldArray2 = [Field.Number(8), Field.Number(12), Field.Str("apple"), Field.Str("pair"), Field.Number(10)]

let column1 = Column(fields: fieldArray2)
let column2 = Column(fields: fieldArray1)

var tab = Table(columns: [column1,column2])
tab.sortColumnsByColumn(0)
// now all columns are sorted