Allow specifying which task to run

main.go

@@ -1,44 +1,75 @@
 package main
 
 import (
+	"flag"
+	"fmt"
 	"log"
 )
 
 func main() {
-	if err := run(); err != nil {
+	var (
+		task   string
+		config string
+	)
+
+	flag.StringVar(&task, "t", "all", "the task to run")
+	flag.StringVar(&config, "c", "config.toml", "the configuration file to use")
+	flag.Parse()
+
+	// Load config
+	cfg, err := LoadConfig(config)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := cfg.LoadTemplates("templates"); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := run(cfg, task); err != nil {
 		log.Fatal(err)
 	}
 }
 
-func run() error {
-	// Load config
-	cfg, err := LoadConfig("config.toml")
-	if err != nil {
-		return err
-	}
-	if err := cfg.LoadTemplates("templates"); err != nil {
-		return err
+func run(cfg *Config, taskName string) error {
+	switch taskName {
+	case "all":
+		return runAll(cfg)
+	default:
+		task, ok := cfg.Tasks[taskName]
+		if !ok {
+			return fmt.Errorf("run task %q: no such task", taskName)
+		}
+		return runTask(cfg, task)
 	}
+}
 
+func runAll(cfg *Config) error {
 	for _, task := range cfg.Tasks {
-		// Load content
-		dir := NewDir("")
-		dir.inputExt = task.Input
-		dir.outputExt = task.Output
-		dir.templateExt = task.Template
-		if err := dir.read("content", ""); err != nil {
-			return err
-		}
-		dir.sort()
-		// Manipulate content
-		if err := dir.manipulate(cfg); err != nil {
-			return err
-		}
-		// Write content
-		if err := dir.write(task.Destination, task); err != nil {
+		err := runTask(cfg, task)
+		if err != nil {
 			return err
 		}
 	}
-
+	return nil
+}
+
+func runTask(cfg *Config, task *Task) error {
+	// Load content
+	dir := NewDir("")
+	dir.inputExt = task.Input
+	dir.outputExt = task.Output
+	dir.templateExt = task.Template
+	if err := dir.read("content", ""); err != nil {
+		return err
+	}
+	dir.sort()
+	// Manipulate content
+	if err := dir.manipulate(cfg); err != nil {
+		return err
+	}
+	// Write content
+	if err := dir.write(task.Destination, task); err != nil {
+		return err
+	}
 	return nil
 }