Modify parsing functions and config structs to accept hcl changes

Signed-off-by: Patrick Van Stee <patrick@vanstee.me>

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

@@ -0,0 +1,233 @@
+package stdlib
+
+import (
+	"fmt"
+	"regexp"
+	resyntax "regexp/syntax"
+
+	"github.com/zclconf/go-cty/cty"
+	"github.com/zclconf/go-cty/cty/function"
+)
+
+var RegexFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "pattern",
+			Type: cty.String,
+		},
+		{
+			Name: "string",
+			Type: cty.String,
+		},
+	},
+	Type: func(args []cty.Value) (cty.Type, error) {
+		if !args[0].IsKnown() {
+			// We can't predict our type without seeing our pattern
+			return cty.DynamicPseudoType, nil
+		}
+
+		retTy, err := regexPatternResultType(args[0].AsString())
+		if err != nil {
+			err = function.NewArgError(0, err)
+		}
+		return retTy, err
+	},
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		if retType == cty.DynamicPseudoType {
+			return cty.DynamicVal, nil
+		}
+
+		re, err := regexp.Compile(args[0].AsString())
+		if err != nil {
+			// Should never happen, since we checked this in the Type function above.
+			return cty.NilVal, function.NewArgErrorf(0, "error parsing pattern: %s", err)
+		}
+		str := args[1].AsString()
+
+		captureIdxs := re.FindStringSubmatchIndex(str)
+		if captureIdxs == nil {
+			return cty.NilVal, fmt.Errorf("pattern did not match any part of the given string")
+		}
+
+		return regexPatternResult(re, str, captureIdxs, retType), nil
+	},
+})
+
+var RegexAllFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "pattern",
+			Type: cty.String,
+		},
+		{
+			Name: "string",
+			Type: cty.String,
+		},
+	},
+	Type: func(args []cty.Value) (cty.Type, error) {
+		if !args[0].IsKnown() {
+			// We can't predict our type without seeing our pattern,
+			// but we do know it'll always be a list of something.
+			return cty.List(cty.DynamicPseudoType), nil
+		}
+
+		retTy, err := regexPatternResultType(args[0].AsString())
+		if err != nil {
+			err = function.NewArgError(0, err)
+		}
+		return cty.List(retTy), err
+	},
+	Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
+		ety := retType.ElementType()
+		if ety == cty.DynamicPseudoType {
+			return cty.DynamicVal, nil
+		}
+
+		re, err := regexp.Compile(args[0].AsString())
+		if err != nil {
+			// Should never happen, since we checked this in the Type function above.
+			return cty.NilVal, function.NewArgErrorf(0, "error parsing pattern: %s", err)
+		}
+		str := args[1].AsString()
+
+		captureIdxsEach := re.FindAllStringSubmatchIndex(str, -1)
+		if len(captureIdxsEach) == 0 {
+			return cty.ListValEmpty(ety), nil
+		}
+
+		elems := make([]cty.Value, len(captureIdxsEach))
+		for i, captureIdxs := range captureIdxsEach {
+			elems[i] = regexPatternResult(re, str, captureIdxs, ety)
+		}
+		return cty.ListVal(elems), nil
+	},
+})
+
+// Regex is a function that extracts one or more substrings from a given
+// string by applying a regular expression pattern, describing the first
+// match.
+//
+// The return type depends on the composition of the capture groups (if any)
+// in the pattern:
+//
+//   - If there are no capture groups at all, the result is a single string
+//     representing the entire matched pattern.
+//   - If all of the capture groups are named, the result is an object whose
+//     keys are the named groups and whose values are their sub-matches, or
+//     null if a particular sub-group was inside another group that didn't
+//     match.
+//   - If none of the capture groups are named, the result is a tuple whose
+//     elements are the sub-groups in order and whose values are their
+//     sub-matches, or null if a particular sub-group was inside another group
+//     that didn't match.
+//   - It is invalid to use both named and un-named capture groups together in
+//     the same pattern.
+//
+// If the pattern doesn't match, this function returns an error. To test for
+// a match, call RegexAll and check if the length of the result is greater
+// than zero.
+func Regex(pattern, str cty.Value) (cty.Value, error) {
+	return RegexFunc.Call([]cty.Value{pattern, str})
+}
+
+// RegexAll is similar to Regex but it finds all of the non-overlapping matches
+// in the given string and returns a list of them.
+//
+// The result type is always a list, whose element type is deduced from the
+// pattern in the same way as the return type for Regex is decided.
+//
+// If the pattern doesn't match at all, this function returns an empty list.
+func RegexAll(pattern, str cty.Value) (cty.Value, error) {
+	return RegexAllFunc.Call([]cty.Value{pattern, str})
+}
+
+// regexPatternResultType parses the given regular expression pattern and
+// returns the structural type that would be returned to represent its
+// capture groups.
+//
+// Returns an error if parsing fails or if the pattern uses a mixture of
+// named and unnamed capture groups, which is not permitted.
+func regexPatternResultType(pattern string) (cty.Type, error) {
+	re, rawErr := regexp.Compile(pattern)
+	switch err := rawErr.(type) {
+	case *resyntax.Error:
+		return cty.NilType, fmt.Errorf("invalid regexp pattern: %s in %s", err.Code, err.Expr)
+	case error:
+		// Should never happen, since all regexp compile errors should
+		// be resyntax.Error, but just in case...
+		return cty.NilType, fmt.Errorf("error parsing pattern: %s", err)
+	}
+
+	allNames := re.SubexpNames()[1:]
+	var names []string
+	unnamed := 0
+	for _, name := range allNames {
+		if name == "" {
+			unnamed++
+		} else {
+			if names == nil {
+				names = make([]string, 0, len(allNames))
+			}
+			names = append(names, name)
+		}
+	}
+	switch {
+	case unnamed == 0 && len(names) == 0:
+		// If there are no capture groups at all then we'll return just a
+		// single string for the whole match.
+		return cty.String, nil
+	case unnamed > 0 && len(names) > 0:
+		return cty.NilType, fmt.Errorf("invalid regexp pattern: cannot mix both named and unnamed capture groups")
+	case unnamed > 0:
+		// For unnamed captures, we return a tuple of them all in order.
+		etys := make([]cty.Type, unnamed)
+		for i := range etys {
+			etys[i] = cty.String
+		}
+		return cty.Tuple(etys), nil
+	default:
+		// For named captures, we return an object using the capture names
+		// as keys.
+		atys := make(map[string]cty.Type, len(names))
+		for _, name := range names {
+			atys[name] = cty.String
+		}
+		return cty.Object(atys), nil
+	}
+}
+
+func regexPatternResult(re *regexp.Regexp, str string, captureIdxs []int, retType cty.Type) cty.Value {
+	switch {
+	case retType == cty.String:
+		start, end := captureIdxs[0], captureIdxs[1]
+		return cty.StringVal(str[start:end])
+	case retType.IsTupleType():
+		captureIdxs = captureIdxs[2:] // index 0 is the whole pattern span, which we ignore by skipping one pair
+		vals := make([]cty.Value, len(captureIdxs)/2)
+		for i := range vals {
+			start, end := captureIdxs[i*2], captureIdxs[i*2+1]
+			if start < 0 || end < 0 {
+				vals[i] = cty.NullVal(cty.String) // Did not match anything because containing group didn't match
+				continue
+			}
+			vals[i] = cty.StringVal(str[start:end])
+		}
+		return cty.TupleVal(vals)
+	case retType.IsObjectType():
+		captureIdxs = captureIdxs[2:] // index 0 is the whole pattern span, which we ignore by skipping one pair
+		vals := make(map[string]cty.Value, len(captureIdxs)/2)
+		names := re.SubexpNames()[1:]
+		for i, name := range names {
+			start, end := captureIdxs[i*2], captureIdxs[i*2+1]
+			if start < 0 || end < 0 {
+				vals[name] = cty.NullVal(cty.String) // Did not match anything because containing group didn't match
+				continue
+			}
+			vals[name] = cty.StringVal(str[start:end])
+		}
+		return cty.ObjectVal(vals)
+	default:
+		// Should never happen
+		panic(fmt.Sprintf("invalid return type %#v", retType))
+	}
+}