Initial pass at command parser

dclish/dclish.go

+// Package dclish A DCL-like command line parser.
+package dclish
+
+import (
+	"fmt"
+	"strings"
+)
+
+// ActionFunc is the function that a command runs.
+type ActionFunc func(string, *Command) error
+
+// Flag is a flag for a command.
+type Flag struct {
+	Name        string
+	Value       string
+	Description string
+}
+
+// Flags is the list of flags.
+type Flags []*Flag
+
+// Command contains the definition of a command, it's flags and subcommands.
+type Command struct {
+	Command     string
+	Flags       Flags
+	Args        []string
+	Commands    []*Command
+	Action      ActionFunc
+	Description string
+}
+
+// Commands is the full list of commands.
+type Commands []*Command
+
+// ParseAndRun parses a command line and runs the command.
+func (c Commands) ParseAndRun(line string) error {
+	// TODO: this doesn't handle a DCL command line completely.
+	words := strings.Fields(line)
+	fmt.Printf("TODO ParseAndRun sees: %s\n", words)
+	cmd := strings.ToUpper(words[0])
+	for i := range c {
+		if c[i].Command == cmd {
+			fmt.Printf("Command help:\n%s\n", c[i].Description)
+			return nil
+		}
+	}
+	fmt.Printf("ERROR: Unknown command '%s'\n", cmd)
+	return nil
+}

repl/repl.go

@@ -3,7 +3,6 @@ package repl
 
 import (
 	"fmt"
-	"strings"
 
 	"github.com/chzyer/readline"
 )
@@ -22,13 +21,12 @@ func Loop(user string) error {
 		if err != nil {
 			return err
 		}
-		words := strings.Field(strings.ReplaceAll(line, "/", " /"))
-		if len(words) {
+		if len(line) == 0 {
 			continue
 		}
-		switch strings.ToUpper(words[0]) {
-		case "ADD":
-			commandAdd()
+		err = commands.ParseAndRun(line)
+		if err != nil {
+			return err
 		}
 	}