Added code for recursively traversing directories

Makefile

@@ -5,9 +5,13 @@ fmt:
 	go fmt ./...
 vet: fmt
 	go vet ./...
-buildLib: vet
+buildLibUnopt: vet
 	go build -gcflags="all=-N -l" ./...
-buildCmd: buildLib
+unopt: buildLibUnopt
 	go build -C kg/ -gcflags="all=-N -l" -o kg ./...
+buildLib: vet
+	go build ./...
+buildCmd: buildLib
+	go build -C kg/ -o kg ./...
 test: buildCmd
 	go test -v ./...

kg/main.go

@@ -5,7 +5,9 @@ import (
 	"flag"
 	"fmt"
 	"io"
+	"io/fs"
 	"os"
+	"path/filepath"
 	"slices"
 
 	"github.com/fatih/color"
@@ -101,7 +103,24 @@ func main() {
 					os.Exit(2)
 				} else {
 					if fileStat.Mode().IsDir() {
-						fmt.Printf("%s: %s: Is a directory\n", os.Args[0], inputFilename)
+						if *recursiveFlag {
+							// Walk the directory and open every file in it. Add each file to the filelist.
+							filepath.WalkDir(inputFilename, func(filename string, d fs.DirEntry, err error) error {
+								if err != nil {
+									return err
+								}
+								if !d.IsDir() {
+									f, err := os.Open(filename)
+									if err != nil {
+										return err
+									}
+									inputFiles = append(inputFiles, f)
+								}
+								return nil
+							})
+						} else {
+							fmt.Printf("%s: %s: Is a directory\n", os.Args[0], inputFilename)
+						}
 					} else {
 						var nullCharPresent bool
 						if nullCharPresent, err = fileContainsNullChar(inputFilename); nullCharPresent {

regex/postfixNode.go

@@ -131,13 +131,9 @@ func newEscapedNode(c rune, inCharClass bool) (postfixNode, error) {
 	case 'v': // Vertical tab
 		toReturn.nodetype = characterNode
 		toReturn.contents = append(toReturn.contents, rune(11))
-	case '-': // Literal hyphen - only in character class
-		if inCharClass {
-			toReturn.nodetype = characterNode
-			toReturn.contents = append(toReturn.contents, '-')
-		} else {
-			return postfixNode{}, fmt.Errorf("invalid escape character")
-		}
+	case '-': // Literal hyphen
+		toReturn.nodetype = characterNode
+		toReturn.contents = append(toReturn.contents, '-')
 	default: // None of the above - append it as a regular character
 		if isNormalChar(c) { // Normal characters cannot be escaped
 			return postfixNode{}, fmt.Errorf("invalid escape character")