feat: better structured internal

internal/cli/arguments.go

@@ -5,18 +5,24 @@ import (
 	"fmt"
 )
 
+// Arguments given to program.
 type CLIOptions struct {
-	Input       string
-	Verbose     bool
+	// The source code given to the program.
+	Input string
+	// Whether or not to print debug logs.
+	Verbose bool
+	// Whether or not to print an explanation of the reduction.
 	Explanation bool
 }
 
-func ParseOptions(args []string) (*CLIOptions, error) {
-	// Parse flags and arguments.
+// Extract the program configuration from the command-line arguments.
+func ParseOptions() (*CLIOptions, error) {
+	// Parse flags.
 	verbose := flag.Bool("v", false, "Verbosity. If set, the program will print logs.")
 	explanation := flag.Bool("x", false, "Explanation. Whether or not to show all reduction steps.")
 	flag.Parse()
 
+	// Parse non-flag arguments.
 	if flag.NArg() == 0 {
 		return nil, fmt.Errorf("No input given.")
 	} else if flag.NArg() > 1 {