package funcs import ( "math" "math/big" "github.com/zclconf/go-cty/cty" "github.com/zclconf/go-cty/cty/function" "github.com/zclconf/go-cty/cty/gocty" ) // LogFunc contructs a function that returns the logarithm of a given number in a given base. var LogFunc = function.New(&function.Spec{ Params: []function.Parameter{ { Name: "num", Type: cty.Number, }, { Name: "base", Type: cty.Number, }, }, Type: function.StaticReturnType(cty.Number), Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) { var num float64 if err := gocty.FromCtyValue(args[0], &num); err != nil { return cty.UnknownVal(cty.String), err } var base float64 if err := gocty.FromCtyValue(args[1], &base); err != nil { return cty.UnknownVal(cty.String), err } return cty.NumberFloatVal(math.Log(num) / math.Log(base)), nil }, }) // PowFunc contructs a function that returns the logarithm of a given number in a given base. var PowFunc = function.New(&function.Spec{ Params: []function.Parameter{ { Name: "num", Type: cty.Number, }, { Name: "power", Type: cty.Number, }, }, Type: function.StaticReturnType(cty.Number), Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) { var num float64 if err := gocty.FromCtyValue(args[0], &num); err != nil { return cty.UnknownVal(cty.String), err } var power float64 if err := gocty.FromCtyValue(args[1], &power); err != nil { return cty.UnknownVal(cty.String), err } return cty.NumberFloatVal(math.Pow(num, power)), nil }, }) // SignumFunc contructs a function that returns the closest whole number greater // than or equal to the given value. var SignumFunc = function.New(&function.Spec{ Params: []function.Parameter{ { Name: "num", Type: cty.Number, }, }, Type: function.StaticReturnType(cty.Number), Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) { var num int if err := gocty.FromCtyValue(args[0], &num); err != nil { return cty.UnknownVal(cty.String), err } switch { case num < 0: return cty.NumberIntVal(-1), nil case num > 0: return cty.NumberIntVal(+1), nil default: return cty.NumberIntVal(0), nil } }, }) // ParseIntFunc contructs a function that parses a string argument and returns an integer of the specified base. var ParseIntFunc = function.New(&function.Spec{ Params: []function.Parameter{ { Name: "number", Type: cty.DynamicPseudoType, }, { Name: "base", Type: cty.Number, }, }, Type: func(args []cty.Value) (cty.Type, error) { if !args[0].Type().Equals(cty.String) { return cty.Number, function.NewArgErrorf(0, "first argument must be a string, not %s", args[0].Type().FriendlyName()) } return cty.Number, nil }, Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) { var numstr string var base int var err error if err = gocty.FromCtyValue(args[0], &numstr); err != nil { return cty.UnknownVal(cty.String), function.NewArgError(0, err) } if err = gocty.FromCtyValue(args[1], &base); err != nil { return cty.UnknownVal(cty.Number), function.NewArgError(1, err) } if base < 2 || base > 62 { return cty.UnknownVal(cty.Number), function.NewArgErrorf( 1, "base must be a whole number between 2 and 62 inclusive", ) } num, ok := (&big.Int{}).SetString(numstr, base) if !ok { return cty.UnknownVal(cty.Number), function.NewArgErrorf( 0, "cannot parse %q as a base %d integer", numstr, base, ) } parsedNum := cty.NumberVal((&big.Float{}).SetInt(num)) return parsedNum, nil }, }) // Log returns returns the logarithm of a given number in a given base. func Log(num, base cty.Value) (cty.Value, error) { return LogFunc.Call([]cty.Value{num, base}) } // Pow returns the logarithm of a given number in a given base. func Pow(num, power cty.Value) (cty.Value, error) { return PowFunc.Call([]cty.Value{num, power}) } // Signum determines the sign of a number, returning a number between -1 and // 1 to represent the sign. func Signum(num cty.Value) (cty.Value, error) { return SignumFunc.Call([]cty.Value{num}) } // ParseInt parses a string argument and returns an integer of the specified base. func ParseInt(num cty.Value, base cty.Value) (cty.Value, error) { return ParseIntFunc.Call([]cty.Value{num, base}) }