Print matched content in color

go.mod

@@ -1,3 +1,10 @@
 module re
 
 go 1.23.1
+
+require (
+	github.com/fatih/color v1.18.0 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	golang.org/x/sys v0.25.0 // indirect
+)

go.sum

@@ -0,0 +1,11 @@
+github.com/fatih/color v1.18.0 h1:S8gINlzdQ840/4pfAwic/ZE0djQEH3wM94VfqLTZcOM=
+github.com/fatih/color v1.18.0/go.mod h1:4FelSpRwEGDpQ12mAdzqdOukCy4u8WUtOY6lkT/6HfU=
+github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
+github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.25.0 h1:r+8e+loiHxRqhXVl6ML1nO3l1+oFoWbnlu2Ehimmi34=
+golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

main.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"os"
 	"slices"
+
+	"github.com/fatih/color"
 )
 
 const CONCAT rune = '~'
@@ -44,7 +46,7 @@ func shuntingYard(re string) string {
 		}
 	}
 
-	fmt.Println(string(re_postfix))
+	// fmt.Println(string(re_postfix))
 
 	opStack := make([]rune, 0)  // Operator stack
 	outQueue := make([]rune, 0) // Output queue
@@ -165,12 +167,19 @@ func main() {
 	var re string
 	re = os.Args[1]
 	re_postfix := shuntingYard(re)
-	fmt.Println(re_postfix)
-	start := thompson(re_postfix)
-	s, e, matched := match(start, os.Args[2])
+	// fmt.Println(re_postfix)
+	startState := thompson(re_postfix)
+	start, end, matched := match(startState, os.Args[2])
 	if matched {
-		fmt.Printf("Matched from %d to %d\n", s, e)
+		for i, c := range os.Args[2] {
+			if i >= start && i < end {
+				color.New(color.FgRed).Printf("%c", c)
+			} else {
+				fmt.Printf("%c", c)
+			}
+		}
+		fmt.Printf("\n")
 	} else {
-		fmt.Printf("No match found.\n")
+		fmt.Println(os.Args[2])
 	}
 }