Update go-cty to pull in more stdlib funcs.

I needed "split" specifically so I can do something like:

```hcl
variable PLATFORMS {
  default = "linux/amd64"
}

target foo {
  platforms = split(",", "${PLATFORMS}")
  # other stuff
}
```

Where the existing "csvdecode" does not work for this because it parses
the string into a list of objects instead of a list of strings.

I went ahead and just added all the available new functions.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

vendor/github.com/zclconf/go-cty/cty/function/stdlib/conversion.go

@@ -0,0 +1,87 @@
+package stdlib
+
+import (
+	"strconv"
+
+	"github.com/zclconf/go-cty/cty"
+	"github.com/zclconf/go-cty/cty/convert"
+	"github.com/zclconf/go-cty/cty/function"
+)
+
+// MakeToFunc constructs a "to..." function, like "tostring", which converts
+// its argument to a specific type or type kind.
+//
+// The given type wantTy can be any type constraint that cty's "convert" package
+// would accept. In particular, this means that you can pass
+// cty.List(cty.DynamicPseudoType) to mean "list of any single type", which
+// will then cause cty to attempt to unify all of the element types when given
+// a tuple.
+func MakeToFunc(wantTy cty.Type) function.Function {
+	return function.New(&function.Spec{
+		Params: []function.Parameter{
+			{
+				Name: "v",
+				// We use DynamicPseudoType rather than wantTy here so that
+				// all values will pass through the function API verbatim and
+				// we can handle the conversion logic within the Type and
+				// Impl functions. This allows us to customize the error
+				// messages to be more appropriate for an explicit type
+				// conversion, whereas the cty function system produces
+				// messages aimed at _implicit_ type conversions.
+				Type:      cty.DynamicPseudoType,
+				AllowNull: true,
+			},
+		},
+		Type: func(args []cty.Value) (cty.Type, error) {
+			gotTy := args[0].Type()
+			if gotTy.Equals(wantTy) {
+				return wantTy, nil
+			}
+			conv := convert.GetConversionUnsafe(args[0].Type(), wantTy)
+			if conv == nil {
+				// We'll use some specialized errors for some trickier cases,
+				// but most we can handle in a simple way.
+				switch {
+				case gotTy.IsTupleType() && wantTy.IsTupleType():
+					return cty.NilType, function.NewArgErrorf(0, "incompatible tuple type for conversion: %s", convert.MismatchMessage(gotTy, wantTy))
+				case gotTy.IsObjectType() && wantTy.IsObjectType():
+					return cty.NilType, function.NewArgErrorf(0, "incompatible object type for conversion: %s", convert.MismatchMessage(gotTy, wantTy))
+				default:
+					return cty.NilType, function.NewArgErrorf(0, "cannot convert %s to %s", gotTy.FriendlyName(), wantTy.FriendlyNameForConstraint())
+				}
+			}
+			// If a conversion is available then everything is fine.
+			return wantTy, nil
+		},
+		Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+			// We didn't set "AllowUnknown" on our argument, so it is guaranteed
+			// to be known here but may still be null.
+			ret, err := convert.Convert(args[0], retType)
+			if err != nil {
+				// Because we used GetConversionUnsafe above, conversion can
+				// still potentially fail in here. For example, if the user
+				// asks to convert the string "a" to bool then we'll
+				// optimistically permit it during type checking but fail here
+				// once we note that the value isn't either "true" or "false".
+				gotTy := args[0].Type()
+				switch {
+				case gotTy == cty.String && wantTy == cty.Bool:
+					what := "string"
+					if !args[0].IsNull() {
+						what = strconv.Quote(args[0].AsString())
+					}
+					return cty.NilVal, function.NewArgErrorf(0, `cannot convert %s to bool; only the strings "true" or "false" are allowed`, what)
+				case gotTy == cty.String && wantTy == cty.Number:
+					what := "string"
+					if !args[0].IsNull() {
+						what = strconv.Quote(args[0].AsString())
+					}
+					return cty.NilVal, function.NewArgErrorf(0, `cannot convert %s to number; given string must be a decimal representation of a number`, what)
+				default:
+					return cty.NilVal, function.NewArgErrorf(0, "cannot convert %s to %s", gotTy.FriendlyName(), wantTy.FriendlyNameForConstraint())
+				}
+			}
+			return ret, nil
+		},
+	})
+}

vendor/github.com/zclconf/go-cty/cty/function/stdlib/datetime.go

@@ -203,6 +203,33 @@ var FormatDateFunc = function.New(&function.Spec{
 	},
 })
 
+// TimeAddFunc is a function that adds a duration to a timestamp, returning a new timestamp.
+var TimeAddFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "timestamp",
+			Type: cty.String,
+		},
+		{
+			Name: "duration",
+			Type: cty.String,
+		},
+	},
+	Type: function.StaticReturnType(cty.String),
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		ts, err := parseTimestamp(args[0].AsString())
+		if err != nil {
+			return cty.UnknownVal(cty.String), err
+		}
+		duration, err := time.ParseDuration(args[1].AsString())
+		if err != nil {
+			return cty.UnknownVal(cty.String), err
+		}
+
+		return cty.StringVal(ts.Add(duration).Format(time.RFC3339)), nil
+	},
+})
+
 // FormatDate reformats a timestamp given in RFC3339 syntax into another time
 // syntax defined by a given format string.
 //
@@ -383,3 +410,20 @@ func splitDateFormat(data []byte, atEOF bool) (advance int, token []byte, err er
 func startsDateFormatVerb(b byte) bool {
 	return (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z')
 }
+
+// TimeAdd adds a duration to a timestamp, returning a new timestamp.
+//
+// In the HCL language, timestamps are conventionally represented as
+// strings using RFC 3339 "Date and Time format" syntax. Timeadd requires
+// the timestamp argument to be a string conforming to this syntax.
+//
+// `duration` is a string representation of a time difference, consisting of
+// sequences of number and unit pairs, like `"1.5h"` or `1h30m`. The accepted
+// units are `ns`, `us` (or `µs`), `"ms"`, `"s"`, `"m"`, and `"h"`. The first
+// number may be negative to indicate a negative duration, like `"-2h5m"`.
+//
+// The result is a string, also in RFC 3339 format, representing the result
+// of adding the given direction to the given timestamp.
+func TimeAdd(timestamp cty.Value, duration cty.Value) (cty.Value, error) {
+	return TimeAddFunc.Call([]cty.Value{timestamp, duration})
+}

vendor/github.com/zclconf/go-cty/cty/function/stdlib/format.go

@@ -6,7 +6,7 @@ import (
 	"math/big"
 	"strings"
 
-	"github.com/apparentlymart/go-textseg/textseg"
+	"github.com/apparentlymart/go-textseg/v12/textseg"
 
 	"github.com/zclconf/go-cty/cty"
 	"github.com/zclconf/go-cty/cty/convert"

vendor/github.com/zclconf/go-cty/cty/function/stdlib/number.go

@@ -2,10 +2,12 @@ package stdlib
 
 import (
 	"fmt"
+	"math"
 	"math/big"
 
 	"github.com/zclconf/go-cty/cty"
 	"github.com/zclconf/go-cty/cty/function"
+	"github.com/zclconf/go-cty/cty/gocty"
 )
 
 var AbsoluteFunc = function.New(&function.Spec{
@@ -358,6 +360,188 @@ var IntFunc = function.New(&function.Spec{
 	},
 })
 
+// CeilFunc is a function that returns the closest whole number greater
+// than or equal to the given value.
+var CeilFunc = 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 val float64
+		if err := gocty.FromCtyValue(args[0], &val); err != nil {
+			return cty.UnknownVal(cty.String), err
+		}
+		if math.IsInf(val, 0) {
+			return cty.NumberFloatVal(val), nil
+		}
+		return cty.NumberIntVal(int64(math.Ceil(val))), nil
+	},
+})
+
+// FloorFunc is a function that returns the closest whole number lesser
+// than or equal to the given value.
+var FloorFunc = 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 val float64
+		if err := gocty.FromCtyValue(args[0], &val); err != nil {
+			return cty.UnknownVal(cty.String), err
+		}
+		if math.IsInf(val, 0) {
+			return cty.NumberFloatVal(val), nil
+		}
+		return cty.NumberIntVal(int64(math.Floor(val))), nil
+	},
+})
+
+// LogFunc is 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 is 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 is a function that determines the sign of a number, returning a
+// number between -1 and 1 to represent the sign..
+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 is 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
+	},
+})
+
 // Absolute returns the magnitude of the given number, without its sign.
 // That is, it turns negative values into positive values.
 func Absolute(num cty.Value) (cty.Value, error) {
@@ -436,3 +620,34 @@ func Int(num cty.Value) (cty.Value, error) {
 	}
 	return IntFunc.Call([]cty.Value{num})
 }
+
+// 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})
+}
+
+// Floor returns the closest whole number lesser than or equal to the given value.
+func Floor(num cty.Value) (cty.Value, error) {
+	return FloorFunc.Call([]cty.Value{num})
+}
+
+// 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})
+}

vendor/github.com/zclconf/go-cty/cty/function/stdlib/string.go

@@ -1,9 +1,13 @@
 package stdlib
 
 import (
+	"fmt"
+	"regexp"
+	"sort"
 	"strings"
 
-	"github.com/apparentlymart/go-textseg/textseg"
+	"github.com/apparentlymart/go-textseg/v12/textseg"
+
 	"github.com/zclconf/go-cty/cty"
 	"github.com/zclconf/go-cty/cty/function"
 	"github.com/zclconf/go-cty/cty/gocty"
@@ -140,8 +144,14 @@ var SubstrFunc = function.New(&function.Spec{
 			}
 
 			offset += totalLen
+		} else if length == 0 {
+			// Short circuit here, after error checks, because if a
+			// string of length 0 has been requested it will always
+			// be the empty string
+			return cty.StringVal(""), nil
 		}
 
+
 		sub := in
 		pos := 0
 		var i int
@@ -187,6 +197,252 @@ var SubstrFunc = function.New(&function.Spec{
 	},
 })
 
+var JoinFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "separator",
+			Type: cty.String,
+		},
+	},
+	VarParam: &function.Parameter{
+		Name: "lists",
+		Type: cty.List(cty.String),
+	},
+	Type: function.StaticReturnType(cty.String),
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		sep := args[0].AsString()
+		listVals := args[1:]
+		if len(listVals) < 1 {
+			return cty.UnknownVal(cty.String), fmt.Errorf("at least one list is required")
+		}
+
+		l := 0
+		for _, list := range listVals {
+			if !list.IsWhollyKnown() {
+				return cty.UnknownVal(cty.String), nil
+			}
+			l += list.LengthInt()
+		}
+
+		items := make([]string, 0, l)
+		for ai, list := range listVals {
+			ei := 0
+			for it := list.ElementIterator(); it.Next(); {
+				_, val := it.Element()
+				if val.IsNull() {
+					if len(listVals) > 1 {
+						return cty.UnknownVal(cty.String), function.NewArgErrorf(ai+1, "element %d of list %d is null; cannot concatenate null values", ei, ai+1)
+					}
+					return cty.UnknownVal(cty.String), function.NewArgErrorf(ai+1, "element %d is null; cannot concatenate null values", ei)
+				}
+				items = append(items, val.AsString())
+				ei++
+			}
+		}
+
+		return cty.StringVal(strings.Join(items, sep)), nil
+	},
+})
+
+var SortFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "list",
+			Type: cty.List(cty.String),
+		},
+	},
+	Type: function.StaticReturnType(cty.List(cty.String)),
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		listVal := args[0]
+
+		if !listVal.IsWhollyKnown() {
+			// If some of the element values aren't known yet then we
+			// can't yet predict the order of the result.
+			return cty.UnknownVal(retType), nil
+		}
+		if listVal.LengthInt() == 0 { // Easy path
+			return listVal, nil
+		}
+
+		list := make([]string, 0, listVal.LengthInt())
+		for it := listVal.ElementIterator(); it.Next(); {
+			iv, v := it.Element()
+			if v.IsNull() {
+				return cty.UnknownVal(retType), fmt.Errorf("given list element %s is null; a null string cannot be sorted", iv.AsBigFloat().String())
+			}
+			list = append(list, v.AsString())
+		}
+
+		sort.Strings(list)
+		retVals := make([]cty.Value, len(list))
+		for i, s := range list {
+			retVals[i] = cty.StringVal(s)
+		}
+		return cty.ListVal(retVals), nil
+	},
+})
+
+var SplitFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "separator",
+			Type: cty.String,
+		},
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+	},
+	Type: function.StaticReturnType(cty.List(cty.String)),
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		sep := args[0].AsString()
+		str := args[1].AsString()
+		elems := strings.Split(str, sep)
+		elemVals := make([]cty.Value, len(elems))
+		for i, s := range elems {
+			elemVals[i] = cty.StringVal(s)
+		}
+		if len(elemVals) == 0 {
+			return cty.ListValEmpty(cty.String), nil
+		}
+		return cty.ListVal(elemVals), nil
+	},
+})
+
+// ChompFunc is a function that removes newline characters at the end of a
+// string.
+var ChompFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+	},
+	Type: function.StaticReturnType(cty.String),
+	Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
+		newlines := regexp.MustCompile(`(?:\r\n?|\n)*\z`)
+		return cty.StringVal(newlines.ReplaceAllString(args[0].AsString(), "")), nil
+	},
+})
+
+// IndentFunc is a function that adds a given number of spaces to the
+// beginnings of all but the first line in a given multi-line string.
+var IndentFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "spaces",
+			Type: cty.Number,
+		},
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+	},
+	Type: function.StaticReturnType(cty.String),
+	Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
+		var spaces int
+		if err := gocty.FromCtyValue(args[0], &spaces); err != nil {
+			return cty.UnknownVal(cty.String), err
+		}
+		data := args[1].AsString()
+		pad := strings.Repeat(" ", spaces)
+		return cty.StringVal(strings.Replace(data, "\n", "\n"+pad, -1)), nil
+	},
+})
+
+// TitleFunc is a function that converts the first letter of each word in the
+// given string to uppercase.
+var TitleFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+	},
+	Type: function.StaticReturnType(cty.String),
+	Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
+		return cty.StringVal(strings.Title(args[0].AsString())), nil
+	},
+})
+
+// TrimSpaceFunc is a function that removes any space characters from the start
+// and end of the given string.
+var TrimSpaceFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+	},
+	Type: function.StaticReturnType(cty.String),
+	Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
+		return cty.StringVal(strings.TrimSpace(args[0].AsString())), nil
+	},
+})
+
+// TrimFunc is a function that removes the specified characters from the start
+// and end of the given string.
+var TrimFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+		{
+			Name: "cutset",
+			Type: cty.String,
+		},
+	},
+	Type: function.StaticReturnType(cty.String),
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		str := args[0].AsString()
+		cutset := args[1].AsString()
+		return cty.StringVal(strings.Trim(str, cutset)), nil
+	},
+})
+
+// TrimPrefixFunc is a function that removes the specified characters from the
+// start the given string.
+var TrimPrefixFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+		{
+			Name: "prefix",
+			Type: cty.String,
+		},
+	},
+	Type: function.StaticReturnType(cty.String),
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		str := args[0].AsString()
+		prefix := args[1].AsString()
+		return cty.StringVal(strings.TrimPrefix(str, prefix)), nil
+	},
+})
+
+// TrimSuffixFunc is a function that removes the specified characters from the
+// end of the given string.
+var TrimSuffixFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+		{
+			Name: "suffix",
+			Type: cty.String,
+		},
+	},
+	Type: function.StaticReturnType(cty.String),
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		str := args[0].AsString()
+		cutset := args[1].AsString()
+		return cty.StringVal(strings.TrimSuffix(str, cutset)), nil
+	},
+})
+
 // Upper is a Function that converts a given string to uppercase.
 func Upper(str cty.Value) (cty.Value, error) {
 	return UpperFunc.Call([]cty.Value{str})
@@ -232,3 +488,60 @@ func Strlen(str cty.Value) (cty.Value, error) {
 func Substr(str cty.Value, offset cty.Value, length cty.Value) (cty.Value, error) {
 	return SubstrFunc.Call([]cty.Value{str, offset, length})
 }
+
+// Join concatenates together the string elements of one or more lists with a
+// given separator.
+func Join(sep cty.Value, lists ...cty.Value) (cty.Value, error) {
+	args := make([]cty.Value, len(lists)+1)
+	args[0] = sep
+	copy(args[1:], lists)
+	return JoinFunc.Call(args)
+}
+
+// Sort re-orders the elements of a given list of strings so that they are
+// in ascending lexicographical order.
+func Sort(list cty.Value) (cty.Value, error) {
+	return SortFunc.Call([]cty.Value{list})
+}
+
+// Split divides a given string by a given separator, returning a list of
+// strings containing the characters between the separator sequences.
+func Split(sep, str cty.Value) (cty.Value, error) {
+	return SplitFunc.Call([]cty.Value{sep, str})
+}
+
+// Chomp removes newline characters at the end of a string.
+func Chomp(str cty.Value) (cty.Value, error) {
+	return ChompFunc.Call([]cty.Value{str})
+}
+
+// Indent adds a given number of spaces to the beginnings of all but the first
+// line in a given multi-line string.
+func Indent(spaces, str cty.Value) (cty.Value, error) {
+	return IndentFunc.Call([]cty.Value{spaces, str})
+}
+
+// Title converts the first letter of each word in the given string to uppercase.
+func Title(str cty.Value) (cty.Value, error) {
+	return TitleFunc.Call([]cty.Value{str})
+}
+
+// TrimSpace removes any space characters from the start and end of the given string.
+func TrimSpace(str cty.Value) (cty.Value, error) {
+	return TrimSpaceFunc.Call([]cty.Value{str})
+}
+
+// Trim removes the specified characters from the start and end of the given string.
+func Trim(str, cutset cty.Value) (cty.Value, error) {
+	return TrimFunc.Call([]cty.Value{str, cutset})
+}
+
+// TrimPrefix removes the specified prefix from the start of the given string.
+func TrimPrefix(str, prefix cty.Value) (cty.Value, error) {
+	return TrimPrefixFunc.Call([]cty.Value{str, prefix})
+}
+
+// TrimSuffix removes the specified suffix from the end of the given string.
+func TrimSuffix(str, suffix cty.Value) (cty.Value, error) {
+	return TrimSuffixFunc.Call([]cty.Value{str, suffix})
+}

vendor/github.com/zclconf/go-cty/cty/function/stdlib/string_replace.go

@@ -0,0 +1,80 @@
+package stdlib
+
+import (
+	"regexp"
+	"strings"
+
+	"github.com/zclconf/go-cty/cty"
+	"github.com/zclconf/go-cty/cty/function"
+)
+
+// ReplaceFunc is a function that searches a given string for another given
+// substring, and replaces each occurence with a given replacement string.
+// The substr argument is a simple string.
+var ReplaceFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+		{
+			Name: "substr",
+			Type: cty.String,
+		},
+		{
+			Name: "replace",
+			Type: cty.String,
+		},
+	},
+	Type: function.StaticReturnType(cty.String),
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		str := args[0].AsString()
+		substr := args[1].AsString()
+		replace := args[2].AsString()
+
+		return cty.StringVal(strings.Replace(str, substr, replace, -1)), nil
+	},
+})
+
+// RegexReplaceFunc is a function that searches a given string for another
+// given substring, and replaces each occurence with a given replacement
+// string. The substr argument must be a valid regular expression.
+var RegexReplaceFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+		{
+			Name: "substr",
+			Type: cty.String,
+		},
+		{
+			Name: "replace",
+			Type: cty.String,
+		},
+	},
+	Type: function.StaticReturnType(cty.String),
+	Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
+		str := args[0].AsString()
+		substr := args[1].AsString()
+		replace := args[2].AsString()
+
+		re, err := regexp.Compile(substr)
+		if err != nil {
+			return cty.UnknownVal(cty.String), err
+		}
+
+		return cty.StringVal(re.ReplaceAllString(str, replace)), nil
+	},
+})
+
+// Replace searches a given string for another given substring,
+// and replaces all occurrences with a given replacement string.
+func Replace(str, substr, replace cty.Value) (cty.Value, error) {
+	return ReplaceFunc.Call([]cty.Value{str, substr, replace})
+}
+
+func RegexReplace(str, substr, replace cty.Value) (cty.Value, error) {
+	return RegexReplaceFunc.Call([]cty.Value{str, substr, replace})
+}