added

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

@@ -0,0 +1,624 @@
+package stdlib
+
+import (
+	"fmt"
+	"regexp"
+	"sort"
+	"strings"
+
+	"github.com/apparentlymart/go-textseg/v13/textseg"
+
+	"github.com/zclconf/go-cty/cty"
+	"github.com/zclconf/go-cty/cty/function"
+	"github.com/zclconf/go-cty/cty/gocty"
+)
+
+var UpperFunc = function.New(&function.Spec{
+	Description: "Returns the given string with all Unicode letters translated to their uppercase equivalents.",
+	Params: []function.Parameter{
+		{
+			Name:             "str",
+			Type:             cty.String,
+			AllowDynamicType: true,
+		},
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		in := args[0].AsString()
+		out := strings.ToUpper(in)
+		return cty.StringVal(out), nil
+	},
+})
+
+var LowerFunc = function.New(&function.Spec{
+	Description: "Returns the given string with all Unicode letters translated to their lowercase equivalents.",
+	Params: []function.Parameter{
+		{
+			Name:             "str",
+			Type:             cty.String,
+			AllowDynamicType: true,
+		},
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		in := args[0].AsString()
+		out := strings.ToLower(in)
+		return cty.StringVal(out), nil
+	},
+})
+
+var ReverseFunc = function.New(&function.Spec{
+	Description: "Returns the given string with all of its Unicode characters in reverse order.",
+	Params: []function.Parameter{
+		{
+			Name:             "str",
+			Type:             cty.String,
+			AllowDynamicType: true,
+		},
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		in := []byte(args[0].AsString())
+		out := make([]byte, len(in))
+		pos := len(out)
+
+		inB := []byte(in)
+		for i := 0; i < len(in); {
+			d, _, _ := textseg.ScanGraphemeClusters(inB[i:], true)
+			cluster := in[i : i+d]
+			pos -= len(cluster)
+			copy(out[pos:], cluster)
+			i += d
+		}
+
+		return cty.StringVal(string(out)), nil
+	},
+})
+
+var StrlenFunc = function.New(&function.Spec{
+	Description: "Returns the number of Unicode characters (technically: grapheme clusters) in the given string.",
+	Params: []function.Parameter{
+		{
+			Name:             "str",
+			Type:             cty.String,
+			AllowUnknown:     true,
+			AllowDynamicType: true,
+		},
+	},
+	Type: function.StaticReturnType(cty.Number),
+	RefineResult: func(b *cty.RefinementBuilder) *cty.RefinementBuilder {
+		// String length is never null and never negative.
+		// (We might refine the lower bound even more inside Impl.)
+		return b.NotNull().NumberRangeLowerBound(cty.NumberIntVal(0), true)
+	},
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		if !args[0].IsKnown() {
+			ret := cty.UnknownVal(cty.Number)
+			// We may be able to still return a constrained result based on the
+			// refined range of the unknown value.
+			inRng := args[0].Range()
+			if inRng.TypeConstraint() == cty.String {
+				prefixLen := int64(graphemeClusterCount(inRng.StringPrefix()))
+				ret = ret.Refine().NumberRangeLowerBound(cty.NumberIntVal(prefixLen), true).NewValue()
+			}
+			return ret, nil
+		}
+
+		in := args[0].AsString()
+		l := graphemeClusterCount(in)
+		return cty.NumberIntVal(int64(l)), nil
+	},
+})
+
+func graphemeClusterCount(in string) int {
+	l := 0
+	inB := []byte(in)
+	for i := 0; i < len(in); {
+		d, _, _ := textseg.ScanGraphemeClusters(inB[i:], true)
+		l++
+		i += d
+	}
+	return l
+}
+
+var SubstrFunc = function.New(&function.Spec{
+	Description: "Extracts a substring from the given string.",
+	Params: []function.Parameter{
+		{
+			Name:             "str",
+			Description:      "The input string.",
+			Type:             cty.String,
+			AllowDynamicType: true,
+		},
+		{
+			Name:             "offset",
+			Description:      "The starting offset in Unicode characters.",
+			Type:             cty.Number,
+			AllowDynamicType: true,
+		},
+		{
+			Name:             "length",
+			Description:      "The maximum length of the result in Unicode characters.",
+			Type:             cty.Number,
+			AllowDynamicType: true,
+		},
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		in := []byte(args[0].AsString())
+		var offset, length int
+
+		var err error
+		err = gocty.FromCtyValue(args[1], &offset)
+		if err != nil {
+			return cty.NilVal, err
+		}
+		err = gocty.FromCtyValue(args[2], &length)
+		if err != nil {
+			return cty.NilVal, err
+		}
+
+		if offset < 0 {
+			totalLenNum, err := Strlen(args[0])
+			if err != nil {
+				// should never happen
+				panic("Stdlen returned an error")
+			}
+
+			var totalLen int
+			err = gocty.FromCtyValue(totalLenNum, &totalLen)
+			if err != nil {
+				// should never happen
+				panic("Stdlen returned a non-int number")
+			}
+
+			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
+
+		// First we'll seek forward to our offset
+		if offset > 0 {
+			for i = 0; i < len(sub); {
+				d, _, _ := textseg.ScanGraphemeClusters(sub[i:], true)
+				i += d
+				pos++
+				if pos == offset {
+					break
+				}
+				if i >= len(in) {
+					return cty.StringVal(""), nil
+				}
+			}
+
+			sub = sub[i:]
+		}
+
+		if length < 0 {
+			// Taking the remainder of the string is a fast path since
+			// we can just return the rest of the buffer verbatim.
+			return cty.StringVal(string(sub)), nil
+		}
+
+		// Otherwise we need to start seeking forward again until we
+		// reach the length we want.
+		pos = 0
+		for i = 0; i < len(sub); {
+			d, _, _ := textseg.ScanGraphemeClusters(sub[i:], true)
+			i += d
+			pos++
+			if pos == length {
+				break
+			}
+		}
+
+		sub = sub[:i]
+
+		return cty.StringVal(string(sub)), nil
+	},
+})
+
+var JoinFunc = function.New(&function.Spec{
+	Description: "Concatenates together the elements of all given lists with a delimiter, producing a single string.",
+	Params: []function.Parameter{
+		{
+			Name:        "separator",
+			Description: "Delimiter to insert between the given strings.",
+			Type:        cty.String,
+		},
+	},
+	VarParam: &function.Parameter{
+		Name:        "lists",
+		Description: "One or more lists of strings to join.",
+		Type:        cty.List(cty.String),
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	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{
+	Description: "Applies a lexicographic sort to the elements of the given list.",
+	Params: []function.Parameter{
+		{
+			Name:         "list",
+			Type:         cty.List(cty.String),
+			AllowUnknown: true,
+		},
+	},
+	Type:         function.StaticReturnType(cty.List(cty.String)),
+	RefineResult: refineNonNull,
+	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, but we can be
+			// sure that the length won't change.
+			ret := cty.UnknownVal(retType)
+			if listVal.Type().IsListType() {
+				rng := listVal.Range()
+				ret = ret.Refine().
+					CollectionLengthLowerBound(rng.LengthLowerBound()).
+					CollectionLengthUpperBound(rng.LengthUpperBound()).
+					NewValue()
+			}
+			return ret, 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{
+	Description: "Produces a list of one or more strings by splitting the given string at all instances of a given separator substring.",
+	Params: []function.Parameter{
+		{
+			Name:        "separator",
+			Description: "The substring that delimits the result strings.",
+			Type:        cty.String,
+		},
+		{
+			Name:        "str",
+			Description: "The string to split.",
+			Type:        cty.String,
+		},
+	},
+	Type:         function.StaticReturnType(cty.List(cty.String)),
+	RefineResult: refineNonNull,
+	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{
+	Description: "Removes one or more newline characters from the end of the given string.",
+	Params: []function.Parameter{
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	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{
+	Description: "Adds a given number of spaces after each newline character in the given string.",
+	Params: []function.Parameter{
+		{
+			Name:        "spaces",
+			Description: "Number of spaces to add after each newline character.",
+			Type:        cty.Number,
+		},
+		{
+			Name:        "str",
+			Description: "The string to transform.",
+			Type:        cty.String,
+		},
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	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{
+	Description: "Replaces one letter after each non-letter and non-digit character with its uppercase equivalent.",
+	Params: []function.Parameter{
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	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{
+	Description: "Removes any consecutive space characters (as defined by Unicode) from the start and end of the given string.",
+	Params: []function.Parameter{
+		{
+			Name: "str",
+			Type: cty.String,
+		},
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	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{
+	Description: "Removes consecutive sequences of characters in \"cutset\" from the start and end of the given string.",
+	Params: []function.Parameter{
+		{
+			Name:        "str",
+			Description: "The string to trim.",
+			Type:        cty.String,
+		},
+		{
+			Name:        "cutset",
+			Description: "A string containing all of the characters to trim. Each character is taken separately, so the order of characters is insignificant.",
+			Type:        cty.String,
+		},
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		str := args[0].AsString()
+		cutset := args[1].AsString()
+		// NOTE: This doesn't properly handle any character that is encoded
+		// with multiple sequential code units, such as letters with
+		// combining diacritics and emoji modifier sequences.
+		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{
+	Description: "Removes the given prefix from the start of the given string, if present.",
+	Params: []function.Parameter{
+		{
+			Name:        "str",
+			Description: "The string to trim.",
+			Type:        cty.String,
+		},
+		{
+			Name:        "prefix",
+			Description: "The prefix to remove, if present.",
+			Type:        cty.String,
+		},
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	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{
+	Description: "Removes the given suffix from the start of the given string, if present.",
+	Params: []function.Parameter{
+		{
+			Name:        "str",
+			Description: "The string to trim.",
+			Type:        cty.String,
+		},
+		{
+			Name:        "suffix",
+			Description: "The suffix to remove, if present.",
+			Type:        cty.String,
+		},
+	},
+	Type:         function.StaticReturnType(cty.String),
+	RefineResult: refineNonNull,
+	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})
+}
+
+// Lower is a Function that converts a given string to lowercase.
+func Lower(str cty.Value) (cty.Value, error) {
+	return LowerFunc.Call([]cty.Value{str})
+}
+
+// Reverse is a Function that reverses the order of the characters in the
+// given string.
+//
+// As usual, "character" for the sake of this function is a grapheme cluster,
+// so combining diacritics (for example) will be considered together as a
+// single character.
+func Reverse(str cty.Value) (cty.Value, error) {
+	return ReverseFunc.Call([]cty.Value{str})
+}
+
+// Strlen is a Function that returns the length of the given string in
+// characters.
+//
+// As usual, "character" for the sake of this function is a grapheme cluster,
+// so combining diacritics (for example) will be considered together as a
+// single character.
+func Strlen(str cty.Value) (cty.Value, error) {
+	return StrlenFunc.Call([]cty.Value{str})
+}
+
+// Substr is a Function that extracts a sequence of characters from another
+// string and creates a new string.
+//
+// As usual, "character" for the sake of this function is a grapheme cluster,
+// so combining diacritics (for example) will be considered together as a
+// single character.
+//
+// The "offset" index may be negative, in which case it is relative to the
+// end of the given string.
+//
+// The "length" may be -1, in which case the remainder of the string after
+// the given offset will be returned.
+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})
+}