diff --git a/capability/policy/selector/parsing.go b/capability/policy/selector/parsing.go
new file mode 100644
index 0000000..f7778c9
--- /dev/null
+++ b/capability/policy/selector/parsing.go
@@ -0,0 +1,160 @@
+package selector
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+func Parse(str string) (Selector, error) {
+	if len(str) == 0 {
+		return nil, newParseError("empty selector", str, 0, "")
+	}
+	if string(str[0]) != "." {
+		return nil, newParseError("selector must start with identity segment '.'", str, 0, string(str[0]))
+	}
+
+	col := 0
+	var sel Selector
+	for _, tok := range tokenize(str) {
+		seg := tok
+		opt := strings.HasSuffix(tok, "?")
+		if opt {
+			seg = tok[0 : len(tok)-1]
+		}
+		switch seg {
+		case ".":
+			if len(sel) > 0 && sel[len(sel)-1].Identity() {
+				return nil, newParseError("selector contains unsupported recursive descent segment: '..'", str, col, tok)
+			}
+			sel = append(sel, Identity)
+		case "[]":
+			sel = append(sel, segment{tok, false, opt, true, nil, "", 0})
+		default:
+			if strings.HasPrefix(seg, "[") && strings.HasSuffix(seg, "]") {
+				lookup := seg[1 : len(seg)-1]
+
+				if indexRegex.MatchString(lookup) { // index
+					idx, err := strconv.Atoi(lookup)
+					if err != nil {
+						return nil, newParseError("invalid index", str, col, tok)
+					}
+					sel = append(sel, segment{str: tok, optional: opt, index: idx})
+				} else if strings.HasPrefix(lookup, "\"") && strings.HasSuffix(lookup, "\"") { // explicit field
+					sel = append(sel, segment{str: tok, optional: opt, field: lookup[1 : len(lookup)-1]})
+				} else if sliceRegex.MatchString(lookup) { // slice [3:5] or [:5] or [3:]
+					var rng []int
+					splt := strings.Split(lookup, ":")
+					if splt[0] == "" {
+						rng = append(rng, 0)
+					} else {
+						i, err := strconv.Atoi(splt[0])
+						if err != nil {
+							return nil, newParseError("invalid slice index", str, col, tok)
+						}
+						rng = append(rng, i)
+					}
+					if splt[1] != "" {
+						i, err := strconv.Atoi(splt[1])
+						if err != nil {
+							return nil, newParseError("invalid slice index", str, col, tok)
+						}
+						rng = append(rng, i)
+					}
+					sel = append(sel, segment{str: tok, optional: opt, slice: rng})
+				} else {
+					return nil, newParseError(fmt.Sprintf("invalid segment: %s", seg), str, col, tok)
+				}
+			} else if fieldRegex.MatchString(seg) {
+				sel = append(sel, segment{str: tok, optional: opt, field: seg[1:]})
+			} else {
+				return nil, newParseError(fmt.Sprintf("invalid segment: %s", seg), str, col, tok)
+			}
+		}
+		col += len(tok)
+	}
+	return sel, nil
+}
+
+func MustParse(sel string) Selector {
+	s, err := Parse(sel)
+	if err != nil {
+		panic(err)
+	}
+	return s
+}
+
+func tokenize(str string) []string {
+	var toks []string
+	col := 0
+	ofs := 0
+	ctx := ""
+
+	for col < len(str) {
+		char := string(str[col])
+
+		if char == "\"" && string(str[col-1]) != "\\" {
+			col++
+			if ctx == "\"" {
+				ctx = ""
+			} else {
+				ctx = "\""
+			}
+			continue
+		}
+
+		if ctx == "\"" {
+			col++
+			continue
+		}
+
+		if char == "." || char == "[" {
+			if ofs < col {
+				toks = append(toks, str[ofs:col])
+			}
+			ofs = col
+		}
+		col++
+	}
+
+	if ofs < col && ctx != "\"" {
+		toks = append(toks, str[ofs:col])
+	}
+
+	return toks
+}
+
+type parseerr struct {
+	msg string
+	src string
+	col int
+	tok string
+}
+
+func (p parseerr) Name() string {
+	return "ParseError"
+}
+
+func (p parseerr) Message() string {
+	return p.msg
+}
+
+func (p parseerr) Column() int {
+	return p.col
+}
+
+func (p parseerr) Error() string {
+	return p.msg
+}
+
+func (p parseerr) Source() string {
+	return p.src
+}
+
+func (p parseerr) Token() string {
+	return p.tok
+}
+
+func newParseError(message string, source string, column int, token string) error {
+	return parseerr{message, source, column, token}
+}
diff --git a/capability/policy/selector/selector.go b/capability/policy/selector/selector.go
index 53b1965..bf2d51e 100644
--- a/capability/policy/selector/selector.go
+++ b/capability/policy/selector/selector.go
@@ -3,7 +3,6 @@ package selector
 import (
 	"fmt"
 	"regexp"
-	"strconv"
 	"strings"
 
 	"github.com/ipld/go-ipld-prime"
@@ -76,159 +75,6 @@ func (s segment) Index() int {
 	return s.index
 }
 
-func Parse(str string) (Selector, error) {
-	if len(str) == 0 {
-		return nil, newParseError("empty selector", str, 0, "")
-	}
-	if string(str[0]) != "." {
-		return nil, newParseError("selector must start with identity segment '.'", str, 0, string(str[0]))
-	}
-
-	col := 0
-	var sel Selector
-	for _, tok := range tokenize(str) {
-		seg := tok
-		opt := strings.HasSuffix(tok, "?")
-		if opt {
-			seg = tok[0 : len(tok)-1]
-		}
-		switch seg {
-		case ".":
-			if len(sel) > 0 && sel[len(sel)-1].Identity() {
-				return nil, newParseError("selector contains unsupported recursive descent segment: '..'", str, col, tok)
-			}
-			sel = append(sel, Identity)
-		case "[]":
-			sel = append(sel, segment{tok, false, opt, true, nil, "", 0})
-		default:
-			if strings.HasPrefix(seg, "[") && strings.HasSuffix(seg, "]") {
-				lookup := seg[1 : len(seg)-1]
-
-				if indexRegex.MatchString(lookup) { // index
-					idx, err := strconv.Atoi(lookup)
-					if err != nil {
-						return nil, newParseError("invalid index", str, col, tok)
-					}
-					sel = append(sel, segment{str: tok, optional: opt, index: idx})
-				} else if strings.HasPrefix(lookup, "\"") && strings.HasSuffix(lookup, "\"") { // explicit field
-					sel = append(sel, segment{str: tok, optional: opt, field: lookup[1 : len(lookup)-1]})
-				} else if sliceRegex.MatchString(lookup) { // slice [3:5] or [:5] or [3:]
-					var rng []int
-					splt := strings.Split(lookup, ":")
-					if splt[0] == "" {
-						rng = append(rng, 0)
-					} else {
-						i, err := strconv.Atoi(splt[0])
-						if err != nil {
-							return nil, newParseError("invalid slice index", str, col, tok)
-						}
-						rng = append(rng, i)
-					}
-					if splt[1] != "" {
-						i, err := strconv.Atoi(splt[1])
-						if err != nil {
-							return nil, newParseError("invalid slice index", str, col, tok)
-						}
-						rng = append(rng, i)
-					}
-					sel = append(sel, segment{str: tok, optional: opt, slice: rng})
-				} else {
-					return nil, newParseError(fmt.Sprintf("invalid segment: %s", seg), str, col, tok)
-				}
-			} else if fieldRegex.MatchString(seg) {
-				sel = append(sel, segment{str: tok, optional: opt, field: seg[1:]})
-			} else {
-				return nil, newParseError(fmt.Sprintf("invalid segment: %s", seg), str, col, tok)
-			}
-		}
-		col += len(tok)
-	}
-	return sel, nil
-}
-
-func tokenize(str string) []string {
-	var toks []string
-	col := 0
-	ofs := 0
-	ctx := ""
-
-	for col < len(str) {
-		char := string(str[col])
-
-		if char == "\"" && string(str[col-1]) != "\\" {
-			col++
-			if ctx == "\"" {
-				ctx = ""
-			} else {
-				ctx = "\""
-			}
-			continue
-		}
-
-		if ctx == "\"" {
-			col++
-			continue
-		}
-
-		if char == "." || char == "[" {
-			if ofs < col {
-				toks = append(toks, str[ofs:col])
-			}
-			ofs = col
-		}
-		col++
-	}
-
-	if ofs < col && ctx != "\"" {
-		toks = append(toks, str[ofs:col])
-	}
-
-	return toks
-}
-
-type parseerr struct {
-	msg string
-	src string
-	col int
-	tok string
-}
-
-func (p parseerr) Name() string {
-	return "ParseError"
-}
-
-func (p parseerr) Message() string {
-	return p.msg
-}
-
-func (p parseerr) Column() int {
-	return p.col
-}
-
-func (p parseerr) Error() string {
-	return p.msg
-}
-
-func (p parseerr) Source() string {
-	return p.src
-}
-
-func (p parseerr) Token() string {
-	return p.tok
-}
-
-func newParseError(message string, source string, column int, token string) error {
-	return parseerr{message, source, column, token}
-}
-
-func MustParse(sel string) Selector {
-	s, err := Parse(sel)
-	if err != nil {
-		panic(err)
-	}
-	return s
-}
-
 // Select uses a selector to extract an IPLD node or set of nodes from the
 // passed subject node.
 func Select(sel Selector, subject ipld.Node) (ipld.Node, []ipld.Node, error) {