1 files changed, 158 insertions, 0 deletions
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..e197b10
--- /dev/null
+++ b/main.go
@@ -0,0 +1,158 @@
+// [PROGRAM] will run a build command and a run command on file system changes.  This is so you can
+// build&run on save.
+// You specify a build command and run command as flags and optionally you can filter by extension.
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+
+	"github.com/fsnotify/fsnotify"
+)
+
+// Colors in escape sequences
+var (
+	Reset    = "\033[0m"
+	BoldCyan = "\033[36m"
+	// Red     = "\033[31m"
+	// Green   = "\033[32m"
+	// Yellow  = "\033[33m"
+	// Blue = "\033[34m"
+	// Magenta = "\033[35m"
+	// Cyan = "\033[36m"
+	// Gray    = "\033[37m"
+	// White   = "\033[97m"
+)
+
+var (
+	// Path in which to look for commands
+	Path string
+	// Command run for building
+	BuildCommand []string
+	// Command run after build
+	RunCommand []string
+	// Command will only run on files that have the Ext extension
+	Ext string
+)
+
+func CompileRun(fileName string) {
+	if !strings.HasSuffix(fileName, Ext) {
+		return
+	}
+
+	// Build the program, exit if return if there was an error
+	{
+		var buildCmd *exec.Cmd
+		if len(BuildCommand) > 1 {
+			buildCmd = exec.Command(BuildCommand[0], append(BuildCommand[1:], fileName)...)
+		} else {
+			buildCmd = exec.Command(BuildCommand[0], fileName)
+		}
+		// run the build command
+		out, err := buildCmd.CombinedOutput()
+
+		if len(BuildCommand) > 1 {
+			fmt.Printf("\n[%s%s %s%s]\n", BoldCyan, BuildCommand[0], strings.Join(append(BuildCommand[1:], fileName), " "), Reset)
+		} else {
+			fmt.Printf("[%s%s %s %s%s]\n", BoldCyan, BuildCommand[0], BuildCommand, fileName, Reset)
+		}
+
+		if len(out) > 0 {
+			fmt.Printf("%s", out)
+		}
+
+		if err != nil {
+			if _, ok := err.(*exec.ExitError); ok {
+				return
+			} else if !ok {
+				panic(err)
+			}
+		}
+	}
+
+	// There was no error in the build so we can execute the run command
+	{
+		var runCmd *exec.Cmd
+		if len(RunCommand) > 1 {
+			runCmd = exec.Command(RunCommand[0], RunCommand[1:]...)
+		} else {
+			runCmd = exec.Command(RunCommand[0])
+		}
+
+		out, err := runCmd.CombinedOutput()
+		if len(RunCommand) > 1 {
+			fmt.Printf("[%s%s %s%s]\n", BoldCyan, RunCommand[0], strings.Join(append(RunCommand[1:]), " "), Reset)
+		} else {
+			fmt.Printf("[%s%s%s]\n", BoldCyan, RunCommand[0], Reset)
+
+		}
+		if len(out) > 0 {
+			fmt.Printf("%s", out)
+		}
+
+		if err != nil {
+			if _, ok := err.(*exec.ExitError); ok {
+				return
+			} else if !ok {
+				panic(err)
+			}
+		}
+	}
+
+}
+
+func main() {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		panic(err)
+	}
+	defer watcher.Close()
+
+	bc := flag.String("b", "", "Command to run for building")
+	rc := flag.String("r", "", "Command for running after build")
+	e := flag.String("e", "", "Filter watched files by suffix")
+	p := flag.String("p", ".", "Path to watch for files")
+	flag.Parse()
+
+	if *bc == "" {
+		fmt.Println("flag is required: -b")
+		os.Exit(1)
+	}
+
+	BuildCommand = strings.Split(*bc, " ")
+	RunCommand = strings.Split(*rc, " ")
+	Ext = *e
+	Path = *p
+
+	fmt.Printf("[%swatching '%s'%s]", BoldCyan, Path, Reset)
+
+	go func() {
+		for {
+			select {
+			case event, ok := <-watcher.Events:
+				if !ok {
+					return
+				}
+				if event.Has(fsnotify.Write) {
+					CompileRun(event.Name)
+				}
+			case err, ok := <-watcher.Errors:
+				if !ok {
+					return
+				}
+				fmt.Println("error:", err)
+			}
+		}
+	}()
+
+	err = watcher.Add(Path)
+	if err != nil {
+		panic(err)
+	}
+
+	<-make(chan struct{})
+}