Swap input output files, allow multiple input, fix string parsing

- Swapped the input filename and output filename on the command line so
  multiple input files could be passed.
- Implemented appending configs when reading multiple input files.  Only
  lables, ranges, and segments are updated.  All other config settings
  are taken from the first input file.
- Fixed string parsing to allow escaping quotes inside a string.

cmd/main.go

@@ -10,11 +10,11 @@ import (
 )
 
 type Arguments struct {
-	Input string `arg:"positional,required"`
-	Output string `arg:"positional"`
+	Output string `arg:"positional,required"`
+	Input []string `arg:"positional,required"`
 
-	RamStart int `arg:"--ram-start" default:"0x5000"`
-	RomStart int `arg:"--rom-start" default:"0xE000"`
+	RamStart int `arg:"--ram-start" default:"0x6000"`
+	RomStart int `arg:"--rom-start" default:"0x8000"`
 }
 
 func main() {
@@ -29,20 +29,41 @@ func main() {
 }
 
 func run(args *Arguments) error {
-	input, err := os.ReadFile(args.Input)
-	if err != nil {
-		return err
+	var config *dasmlbl.Config
+	var err error
+
+	for _, infile := range args.Input {
+		input, err := os.ReadFile(infile)
+		if err != nil {
+			return err
+		}
+
+
+		l, ch := dasmlbl.NewLexer(string(input))
+		go l.Run()
+
+		parser := dasmlbl.NewParser(ch)
+		cfg, err := parser.Run()
+		if err != nil {
+			fmt.Printf("[%s] %s\n", infile, err)
+		}
+
+		if config == nil {
+			config = cfg
+		} else {
+			config.Append(cfg)
+		}
 	}
 
-	l, ch := dasmlbl.NewLexer(string(input))
-	go l.Run()
-
-	parser := dasmlbl.NewParser(ch)
-	config, err := parser.Run()
-	if err != nil {
-		fmt.Println(err)
+	if config == nil {
+		return fmt.Errorf("no configs parsed")
 	}
 
+	//input, err := os.ReadFile(args.Input)
+	//if err != nil {
+	//	return err
+	//}
+
 	var output *os.File
 	if args.Output == "" {
 		output = os.Stdout

config.go

@@ -30,6 +30,12 @@ type Config struct {
 	Segments []Segment
 }
 
+func (c *Config) Append(other *Config) {
+	c.Labels = append(c.Labels, other.Labels...)
+	c.Ranges = append(c.Ranges, other.Ranges...)
+	c.Segments = append(c.Segments, other.Segments...)
+}
+
 type Label struct {
 	Name      string
 	Address   int

lex.go

@@ -61,6 +61,19 @@ func (l *Lexer) next() rune {
 	return r
 }
 
+func (l *Lexer) peek() rune {
+	if l.pos >= len(l.input) {
+		l.width = 0
+		return unicode_EOF
+	}
+
+	r, size := utf8.DecodeRuneInString(l.input[l.pos:])
+	if size == 0 {
+		panic(fmt.Sprintf("zero width at %d", l.pos))
+	}
+	return r
+}
+
 func (l *Lexer) backup() {
 	l.pos -= l.width
 }
@@ -177,6 +190,13 @@ func lexString(l *Lexer) stateFn {
 			l.items <- LexItem{lex_Error, "EOF before string end"}
 			return nil
 		}
+
+		if r == '\\' && l.peek() == '"' {
+			r = l.next()
+			//fmt.Printf("consuming %c\n", r) // consume
+			continue
+		}
+
 		if r == '"' {
 			break
 		}

parse.go

@@ -139,7 +139,7 @@ func (p *Parser) parseRange() error {
 
 		itm = p.next()
 		if itm.typ != lex_Semicolon {
-			return fmt.Errorf("missing semicolon")
+			return fmt.Errorf("[parseRange] missing semicolon")
 		}
 	}
 
@@ -213,7 +213,7 @@ func (p *Parser) parseLabel() error {
 
 		itm = p.next()
 		if itm.typ != lex_Semicolon {
-			return fmt.Errorf("missing semicolon")
+			return fmt.Errorf("[parseLabel] missing semicolon; %#v", lbl)
 		}
 	}