[script] Better auto label support

Labels are now their own object instead of just a string.  This allows
for a bit more control with them.  Labels can also now have comments.

Additionally, add the ability to load user-defined labels from a file.
The format of this file is subject to change, but for now it is just a
simple text file.  Each line of the file is a label definition.  Each
line has three fields, separated by spaces.  The first field is the
address, second is the label name, and the rest of the line is a
comment.  If a label name is just a dollar sign ($) it will not have a
name.  This is used when adding comments without a bespoke label.

cmd/script-decode.go

@@ -5,8 +5,11 @@ import (
 	"os"
 	"strings"
 	"strconv"
+	"bufio"
+	"slices"
 
 	"github.com/alexflint/go-arg"
+
 	"git.zorchenhimer.com/Zorchenhimer/go-studybox/script"
 )
 
@@ -14,6 +17,8 @@ type Arguments struct {
 	Input string `arg:"positional,required"`
 	Output string `arg:"positional"`
 	StartAddr string `arg:"--start" default:"0x6000" help:"base address for the start of the script"`
+	LabelFile string `arg:"--labels" help:"file containing address/label pairs"`
+
 	start int
 }
 
@@ -38,6 +43,18 @@ func run(args *Arguments) error {
 		return err
 	}
 
+	if args.LabelFile != "" {
+		labels, err := parseLabelFile(args.LabelFile)
+		if err != nil {
+			return err
+		}
+
+		for _, label := range labels {
+			//fmt.Printf("%#v\n", label)
+			scr.Labels[label.Address] = label
+		}
+	}
+
 	outfile := os.Stdout
 	if args.Output != "" {
 		outfile, err = os.Create(args.Output)
@@ -64,6 +81,62 @@ func run(args *Arguments) error {
 	return nil
 }
 
+func parseLabelFile(filename string) ([]*script.Label, error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	labels := []*script.Label{}
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+
+		line = strings.ReplaceAll(line, "\t", " ")
+		parts := strings.Split(line, " ")
+
+		parts = slices.DeleteFunc(parts, func(str string) bool {
+			return str == ""
+		})
+
+		if len(parts) < 2 {
+			fmt.Println("Ignoring", line)
+			continue
+		}
+
+		if strings.HasPrefix(parts[0], "$") {
+			parts[0] = "0x"+parts[0][1:]
+		}
+
+		addr, err := strconv.ParseInt(parts[0], 0, 32)
+		if err != nil {
+			fmt.Printf("Address parse error for %q: %s\n", line, err)
+			continue
+		}
+
+		lbl := &script.Label{
+			Name: parts[1],
+			Address: int(addr),
+		}
+
+		if lbl.Name == "$" {
+			lbl.Name = ""
+		}
+
+		if len(parts) > 2 {
+			lbl.Comment = strings.Join(parts[2:], " ")
+		}
+
+		labels = append(labels, lbl)
+	}
+
+	return labels, nil
+}
+
 func main() {
 	args := &Arguments{}
 	arg.MustParse(args)

script/parser.go

@@ -5,6 +5,42 @@ import (
 	"os"
 )
 
+type Label struct {
+	Address int
+	Name string
+	Comment string
+	FarLabel bool
+}
+
+func AutoLabel(address int) *Label {
+	return &Label{
+		Address: address,
+		Name: fmt.Sprintf("L%04X", address),
+	}
+}
+
+func AutoLabelVar(address int) *Label {
+	return &Label{
+		Address: address,
+		Name: fmt.Sprintf("Var_%04X", address),
+	}
+}
+
+func AutoLabelFar(address int) *Label {
+	return &Label{
+		Address: address,
+		Name: fmt.Sprintf("F%04X", address),
+		FarLabel: true,
+	}
+}
+
+func NewLabel(address int, name string) *Label {
+	return &Label{
+		Address: address,
+		Name: name,
+	}
+}
+
 func ParseFile(filename string, startAddr int) (*Script, error) {
 	rawfile, err := os.ReadFile(filename)
 	if err != nil {
@@ -24,7 +60,7 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 		Warnings: []string{},
 		StackAddress: (int(rawinput[1])<<8) | int(rawinput[0]),
 		StartAddress: startAddr,
-		Labels: make(map[int]string), // map[location]name
+		Labels: make(map[int]*Label), // map[location]name
 	}
 	tokenMap := make(map[int]*Token)
 
@@ -112,7 +148,7 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 				if tok.Offset == addr {
 					tok.IsTarget = true
 					found = true
-					script.Labels[addr] = fmt.Sprintf("L%04X", addr)
+					script.Labels[addr] = AutoLabel(addr) //fmt.Sprintf("L%04X", addr)
 					break
 				}
 			}
@@ -133,7 +169,7 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 					if tok.Offset == addr {
 						tok.IsTarget = true
 						found = true
-						script.Labels[addr] = fmt.Sprintf("L%04X", addr)
+						script.Labels[addr] = AutoLabel(addr) //fmt.Sprintf("L%04X", addr)
 						break
 					}
 				}
@@ -152,7 +188,7 @@ func Parse(rawinput []byte, startAddr int) (*Script, error) {
 				addr := t.Inline[0].Int()
 				if tok, ok := tokenMap[addr]; ok {
 					tok.IsVariable = true
-					script.Labels[addr] = fmt.Sprintf("Var_%04X", addr)
+					script.Labels[addr] = AutoLabelVar(addr) //fmt.Sprintf("Var_%04X", addr)
 				}
 			}
 		}

script/script.go

@@ -10,5 +10,6 @@ type Script struct {
 	StartAddress int
 	StackAddress int
 
-	Labels map[int]string
+	//Labels map[int]string
+	Labels map[int]*Label
 }

script/tokens.go

@@ -15,7 +15,7 @@ type Token struct {
 	Instruction *Instruction
 }
 
-func (t Token) String(labels map[int]string) string {
+func (t Token) String(labels map[int]*Label) string {
 	suffix := ""
 	switch t.Raw {
 	case 0x86:
@@ -25,10 +25,18 @@ func (t Token) String(labels map[int]string) string {
 	prefix := ""
 	if t.IsTarget || t.IsVariable {
 		if lbl, ok := labels[t.Offset]; ok {
-			prefix = "\n"+lbl+":\n"
+			comment := ""
+			if lbl.Comment != "" {
+				comment = "; "+lbl.Comment+"\n"
+			}
+			prefix = "\n"+comment+lbl.Name+":\n"
 		} else {
 			prefix = fmt.Sprintf("\nL%04X:\n", t.Offset)
 		}
+	} else {
+		if lbl, ok := labels[t.Offset]; ok && lbl.Comment != "" {
+			suffix = " ; "+lbl.Comment+suffix
+		}
 	}
 
 	if t.Raw < 0x80 {
@@ -56,7 +64,7 @@ func (t Token) String(labels map[int]string) string {
 	argstr := []string{}
 	for _, a := range t.Inline {
 		if lbl, ok := labels[a.Int()]; ok {
-			argstr = append(argstr, lbl)
+			argstr = append(argstr, lbl.Name)
 		} else {
 			argstr = append(argstr, a.HexString())
 		}