feat(command): add command parsing

commandParse.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"strings"
+)
+
+func getTextMiddle(text, left, right string) string {
+	start := 0
+	if left != "" {
+		idx := strings.Index(text, left)
+		if idx == -1 {
+			return ""
+		}
+		start = idx + len(left)
+	}
+
+	if right == "" {
+		if start > len(text) {
+			return ""
+		}
+		return text[start:]
+	}
+
+	endIdx := strings.Index(text[start:], right)
+	if endIdx == -1 {
+		return ""
+	}
+	return text[start : start+endIdx]
+}
+
+func getCommand(content string) string {
+	return getTextMiddle(content, "[", "]")
+}
+
+func parseCommand(content, cmdType string) string {
+	return getTextMiddle(content, "<" + cmdType + ">", "</" + cmdType + ">")
+}
+
+func executeCommand(input string) error {
+	return nil
+}