Merge pull request #181 from hashicorp/cherry-pick-22747

lang/funcs: parseint function (cherry-pick hashicorp/terraform#22747)

Author: kmoe

internal/lang/funcs/number.go

@@ -2,6 +2,7 @@ package funcs
 
 import (
 	"math"
+	"math/big"
 
 	"github.com/zclconf/go-cty/cty"
 	"github.com/zclconf/go-cty/cty/function"
@@ -128,6 +129,62 @@ var SignumFunc = function.New(&function.Spec{
 	},
 })
 
+// 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
+	},
+})
+
 // Ceil returns the closest whole number greater than or equal to the given value.
 func Ceil(num cty.Value) (cty.Value, error) {
 	return CeilFunc.Call([]cty.Value{num})
@@ -153,3 +210,8 @@ func Pow(num, power cty.Value) (cty.Value, error) {
 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})
+}

internal/lang/funcs/number_test.go

@@ -257,3 +257,164 @@ func TestSignum(t *testing.T) {
 		})
 	}
 }
+
+func TestParseInt(t *testing.T) {
+	tests := []struct {
+		Num  cty.Value
+		Base cty.Value
+		Want cty.Value
+		Err  bool
+	}{
+		{
+			cty.StringVal("128"),
+			cty.NumberIntVal(10),
+			cty.NumberIntVal(128),
+			false,
+		},
+		{
+			cty.StringVal("-128"),
+			cty.NumberIntVal(10),
+			cty.NumberIntVal(-128),
+			false,
+		},
+		{
+			cty.StringVal("00128"),
+			cty.NumberIntVal(10),
+			cty.NumberIntVal(128),
+			false,
+		},
+		{
+			cty.StringVal("-00128"),
+			cty.NumberIntVal(10),
+			cty.NumberIntVal(-128),
+			false,
+		},
+		{
+			cty.StringVal("FF00"),
+			cty.NumberIntVal(16),
+			cty.NumberIntVal(65280),
+			false,
+		},
+		{
+			cty.StringVal("ff00"),
+			cty.NumberIntVal(16),
+			cty.NumberIntVal(65280),
+			false,
+		},
+		{
+			cty.StringVal("-FF00"),
+			cty.NumberIntVal(16),
+			cty.NumberIntVal(-65280),
+			false,
+		},
+		{
+			cty.StringVal("00FF00"),
+			cty.NumberIntVal(16),
+			cty.NumberIntVal(65280),
+			false,
+		},
+		{
+			cty.StringVal("-00FF00"),
+			cty.NumberIntVal(16),
+			cty.NumberIntVal(-65280),
+			false,
+		},
+		{
+			cty.StringVal("1011111011101111"),
+			cty.NumberIntVal(2),
+			cty.NumberIntVal(48879),
+			false,
+		},
+		{
+			cty.StringVal("aA"),
+			cty.NumberIntVal(62),
+			cty.NumberIntVal(656),
+			false,
+		},
+		{
+			cty.StringVal("Aa"),
+			cty.NumberIntVal(62),
+			cty.NumberIntVal(2242),
+			false,
+		},
+		{
+			cty.StringVal("999999999999999999999999999999999999999999999999999999999999"),
+			cty.NumberIntVal(10),
+			cty.MustParseNumberVal("999999999999999999999999999999999999999999999999999999999999"),
+			false,
+		},
+		{
+			cty.StringVal("FF"),
+			cty.NumberIntVal(10),
+			cty.UnknownVal(cty.Number),
+			true,
+		},
+		{
+			cty.StringVal("00FF"),
+			cty.NumberIntVal(10),
+			cty.UnknownVal(cty.Number),
+			true,
+		},
+		{
+			cty.StringVal("-00FF"),
+			cty.NumberIntVal(10),
+			cty.UnknownVal(cty.Number),
+			true,
+		},
+		{
+			cty.NumberIntVal(2),
+			cty.NumberIntVal(10),
+			cty.UnknownVal(cty.Number),
+			true,
+		},
+		{
+			cty.StringVal("1"),
+			cty.NumberIntVal(63),
+			cty.UnknownVal(cty.Number),
+			true,
+		},
+		{
+			cty.StringVal("1"),
+			cty.NumberIntVal(-1),
+			cty.UnknownVal(cty.Number),
+			true,
+		},
+		{
+			cty.StringVal("1"),
+			cty.NumberIntVal(1),
+			cty.UnknownVal(cty.Number),
+			true,
+		},
+		{
+			cty.StringVal("1"),
+			cty.NumberIntVal(0),
+			cty.UnknownVal(cty.Number),
+			true,
+		},
+		{
+			cty.StringVal("1.2"),
+			cty.NumberIntVal(10),
+			cty.UnknownVal(cty.Number),
+			true,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(fmt.Sprintf("parseint(%#v, %#v)", test.Num, test.Base), func(t *testing.T) {
+			got, err := ParseInt(test.Num, test.Base)
+
+			if test.Err {
+				if err == nil {
+					t.Fatal("succeeded; want error")
+				}
+				return
+			} else if err != nil {
+				t.Fatalf("unexpected error: %s", err)
+			}
+
+			if !got.RawEquals(test.Want) {
+				t.Errorf("wrong result\ngot:  %#v\nwant: %#v", got, test.Want)
+			}
+		})
+	}
+}

internal/lang/functions.go

@@ -83,6 +83,7 @@ func (s *Scope) Functions() map[string]function.Function {
 			"md5":              funcs.Md5Func,
 			"merge":            funcs.MergeFunc,
 			"min":              stdlib.MinFunc,
+			"parseint":         funcs.ParseIntFunc,
 			"pathexpand":       funcs.PathExpandFunc,
 			"pow":              funcs.PowFunc,
 			"range":            stdlib.RangeFunc,

internal/lang/functions_test.go

@@ -513,6 +513,13 @@ func TestFunctions(t *testing.T) {
 			},
 		},
 
+		"parseint": {
+			{
+				`parseint("100", 10)`,
+				cty.NumberIntVal(100),
+			},
+		},
+
 		"pathexpand": {
 			{
 				`pathexpand("~/test-file")`,