Making a mess with a parser that works more like go/parser

node.go

@@ -7,6 +7,10 @@ type TypedNode struct {
 	Node Node   `json:"node"`
 }
 
+type PassthroughArgs struct {
+	Nodes []Node `json:"nodes"`
+}
+
 type CompoundShortFlag struct {
 	Nodes []Node `json:"nodes"`
 }
@@ -21,6 +25,12 @@ type Ident struct {
 	Literal string `json:"literal"`
 }
 
+type BadArg struct {
+	Literal string
+	From    Pos
+	To      Pos
+}
+
 type Command struct {
 	Name   string            `json:"name"`
 	Values map[string]string `json:"values"`

parser.go

@@ -10,24 +10,10 @@ import (
 	"github.com/pkg/errors"
 )
 
-const (
-	OneOrMoreValue  NValue = -2
-	ZeroOrMoreValue NValue = -1
-	ZeroValue       NValue = 0
-)
-
 var (
 	ErrSyntax = errors.New("syntax error")
-
-	DefaultParserConfig = &ParserConfig{
-		Commands:      map[string]CommandConfig{},
-		Flags:         map[string]FlagConfig{},
-		ScannerConfig: DefaultScannerConfig,
-	}
 )
 
-type NValue int
-
 func ParseArgs(args []string, pCfg *ParserConfig) (*ParseTree, error) {
 	reEncoded := strings.Join(args, string(nul))
 
@@ -55,26 +41,7 @@ type ParseTree struct {
 type scanEntry struct {
 	tok Token
 	lit string
-	pos int
-}
-
-type ParserConfig struct {
-	Prog     CommandConfig
-	Commands map[string]CommandConfig
-	Flags    map[string]FlagConfig
-
-	ScannerConfig *ScannerConfig
-}
-
-type CommandConfig struct {
-	NValue     NValue
-	ValueNames []string
-	Flags      map[string]FlagConfig
-}
-
-type FlagConfig struct {
-	NValue     NValue
-	ValueNames []string
+	pos Pos
 }
 
 func NewParser(r io.Reader, pCfg *ParserConfig) *Parser {
@@ -314,7 +281,7 @@ func (p *Parser) scanIdent() (string, error) {
 	unscanBuf := []scanEntry{}
 
 	if tok == ASSIGN || tok == ARG_DELIMITER {
-		entry := scanEntry{tok: tok, lit: lit, pos: pos}
+		entry := scanEntry{tok: tok, lit: lit, pos: Pos(pos)}
 
 		tracef("scanIdent tok=%s; scanning next and pushing to unscan buffer entry=%+#v", tok, entry)
 
@@ -327,7 +294,7 @@ func (p *Parser) scanIdent() (string, error) {
 		return lit, nil
 	}
 
-	entry := scanEntry{tok: tok, lit: lit, pos: pos}
+	entry := scanEntry{tok: tok, lit: lit, pos: Pos(pos)}
 
 	tracef("scanIdent tok=%s; unscanning entry=%+#v", tok, entry)
 
@@ -340,7 +307,7 @@ func (p *Parser) scanIdent() (string, error) {
 	return "", errors.Wrapf(ErrSyntax, "expected ident at pos=%v but got %s (%q)", pos, tok, lit)
 }
 
-func (p *Parser) scan() (Token, string, int) {
+func (p *Parser) scan() (Token, string, Pos) {
 	if len(p.buf) != 0 {
 		entry, buf := p.buf[len(p.buf)-1], p.buf[:len(p.buf)-1]
 		p.buf = buf
@@ -356,7 +323,7 @@ func (p *Parser) scan() (Token, string, int) {
 	return tok, lit, pos
 }
 
-func (p *Parser) unscan(tok Token, lit string, pos int) {
+func (p *Parser) unscan(tok Token, lit string, pos Pos) {
 	entry := scanEntry{tok: tok, lit: lit, pos: pos}
 
 	tracef("unscan entry=%s %+#v", tok, entry)

parser2.go

@@ -0,0 +1,188 @@
+package argh
+
+import (
+	"fmt"
+	"io"
+	"strings"
+)
+
+type parser2 struct {
+	s *Scanner
+
+	commands map[string]struct{}
+
+	errors ScannerErrorList
+
+	tok Token
+	lit string
+	pos Pos
+}
+
+func ParseArgs2(args, commands []string) (*ParseTree, error) {
+	parser := &parser2{}
+	parser.init(
+		strings.NewReader(strings.Join(args, string(nul))),
+		commands,
+	)
+
+	tracef("ParseArgs2 parser=%+#v", parser)
+
+	return parser.parseArgs()
+}
+
+func (p *parser2) init(r io.Reader, commands []string) {
+	p.errors = ScannerErrorList{}
+	commandMap := map[string]struct{}{}
+
+	for _, c := range commands {
+		commandMap[c] = struct{}{}
+	}
+
+	p.s = NewScanner(r, nil)
+	p.commands = commandMap
+
+	p.next()
+}
+
+func (p *parser2) parseArgs() (*ParseTree, error) {
+	if p.errors.Len() != 0 {
+		tracef("parseArgs bailing due to initial error")
+		return nil, p.errors.Err()
+	}
+
+	prog := &Program{
+		Name:   p.lit,
+		Values: map[string]string{},
+		Nodes:  []Node{},
+	}
+	p.next()
+
+	for p.tok != EOL && p.tok != STOP_FLAG {
+		prog.Nodes = append(prog.Nodes, p.parseArg())
+	}
+
+	return &ParseTree{
+		Nodes: []Node{
+			prog, p.parsePassthrough(),
+		},
+	}, nil
+}
+
+func (p *parser2) next() {
+	tracef("parser2.next() <- %v %q %v", p.tok, p.lit, p.pos)
+	defer func() {
+		tracef("parser2.next() -> %v %q %v", p.tok, p.lit, p.pos)
+	}()
+
+	p.tok, p.lit, p.pos = p.s.Scan()
+}
+
+func (p *parser2) parseArg() Node {
+	switch p.tok {
+	case ARG_DELIMITER:
+		p.next()
+		return &ArgDelimiter{}
+	case IDENT:
+		if _, ok := p.commands[p.lit]; ok {
+			return p.parseCommand()
+		}
+		return p.parseIdent()
+	case LONG_FLAG, SHORT_FLAG, COMPOUND_SHORT_FLAG:
+		return p.parseFlag()
+	}
+
+	pos := p.pos
+	lit := p.lit
+	p.advanceArg()
+	return &BadArg{Literal: lit, From: pos, To: p.pos}
+}
+
+func (p *parser2) advanceArg() {
+	for ; p.tok != EOL; p.next() {
+		switch p.tok {
+		case IDENT, LONG_FLAG, SHORT_FLAG, COMPOUND_SHORT_FLAG:
+			return
+		}
+	}
+}
+
+func (p *parser2) parseCommand() Node {
+	node := &Command{Name: p.lit, Values: map[string]string{}, Nodes: []Node{}}
+
+	for i := 0; p.tok != EOL; i++ {
+		p.next()
+
+		if _, ok := p.commands[p.lit]; ok {
+			break
+		}
+
+		switch p.tok {
+		case ARG_DELIMITER:
+			continue
+		case IDENT, STDIN_FLAG:
+			node.Values[fmt.Sprintf("%d", i)] = p.lit
+		case LONG_FLAG, SHORT_FLAG, COMPOUND_SHORT_FLAG:
+			node.Nodes = append(node.Nodes, p.parseFlag())
+		default:
+			break
+		}
+	}
+
+	return node
+}
+
+func (p *parser2) parseIdent() Node {
+	defer p.next()
+
+	node := &Ident{Literal: p.lit}
+	return node
+}
+
+func (p *parser2) parseFlag() Node {
+	defer p.next()
+
+	switch p.tok {
+	case SHORT_FLAG:
+		return p.parseShortFlag()
+	case LONG_FLAG:
+		return p.parseLongFlag()
+	case COMPOUND_SHORT_FLAG:
+		return p.parseCompoundShortFlag()
+	}
+
+	panic(fmt.Sprintf("token %v cannot be parsed as flag", p.tok))
+}
+
+func (p *parser2) parseShortFlag() Node {
+	node := &Flag{Name: string(p.lit[1])}
+	// TODO: moar stuff
+	return node
+}
+
+func (p *parser2) parseLongFlag() Node {
+	node := &Flag{Name: string(p.lit[2:])}
+	// TODO: moar stuff
+	return node
+}
+
+func (p *parser2) parseCompoundShortFlag() Node {
+	flagNodes := []Node{}
+
+	withoutFlagPrefix := p.lit[1:]
+
+	for _, r := range withoutFlagPrefix {
+		flagNodes = append(flagNodes, &Flag{Name: string(r)})
+	}
+
+	return &CompoundShortFlag{Nodes: flagNodes}
+}
+
+func (p *parser2) parsePassthrough() Node {
+	nodes := []Node{}
+
+	for ; p.tok != EOL; p.next() {
+		nodes = append(nodes, &Ident{Literal: p.lit})
+	}
+
+	return &PassthroughArgs{Nodes: nodes}
+}

parser2_test.go

@@ -0,0 +1,36 @@
+package argh_test
+
+import (
+	"testing"
+
+	"git.meatballhat.com/x/box-o-sand/argh"
+	"github.com/davecgh/go-spew/spew"
+)
+
+func TestParser2(t *testing.T) {
+	for _, tc := range []struct {
+		name     string
+		args     []string
+		commands []string
+	}{
+		{
+			name: "basic",
+			args: []string{
+				"pies", "-eat", "--wat", "hello",
+			},
+			commands: []string{
+				"hello",
+			},
+		},
+	} {
+		t.Run(tc.name, func(ct *testing.T) {
+			pt, err := argh.ParseArgs2(tc.args, tc.commands)
+			if err != nil {
+				ct.Logf("err=%+#v", err)
+				return
+			}
+
+			spew.Dump(pt)
+		})
+	}
+}

parser_config.go

@@ -0,0 +1,37 @@
+package argh
+
+const (
+	OneOrMoreValue  NValue = -2
+	ZeroOrMoreValue NValue = -1
+	ZeroValue       NValue = 0
+)
+
+var (
+	DefaultParserConfig = &ParserConfig{
+		Commands:      map[string]CommandConfig{},
+		Flags:         map[string]FlagConfig{},
+		ScannerConfig: DefaultScannerConfig,
+	}
+)
+
+type NValue int
+
+type ParserConfig struct {
+	Prog     CommandConfig
+	Commands map[string]CommandConfig
+	Flags    map[string]FlagConfig
+
+	ScannerConfig *ScannerConfig
+}
+
+type CommandConfig struct {
+	NValue     NValue
+	ValueNames []string
+	Flags      map[string]FlagConfig
+	Commands   map[string]CommandConfig
+}
+
+type FlagConfig struct {
+	NValue     NValue
+	ValueNames []string
+}

scanner.go

@@ -4,8 +4,10 @@ import (
 	"bufio"
 	"bytes"
 	"errors"
+	"fmt"
 	"io"
 	"log"
+	"sort"
 	"unicode"
 )
 
@@ -34,6 +36,74 @@ type ScannerConfig struct {
 	MultiValueDelim    rune
 }
 
+// ScannerError is largely borrowed from go/scanner.Error
+type ScannerError struct {
+	Pos Position
+	Msg string
+}
+
+func (e ScannerError) Error() string {
+	if e.Pos.IsValid() {
+		return e.Pos.String() + ":" + e.Msg
+	}
+	return e.Msg
+}
+
+// ScannerErrorList is largely borrowed from go/scanner.ErrorList
+type ScannerErrorList []*ScannerError
+
+func (el *ScannerErrorList) Add(pos Position, msg string) {
+	*el = append(*el, &ScannerError{Pos: pos, Msg: msg})
+}
+
+func (el *ScannerErrorList) Reset() { *el = (*el)[0:0] }
+
+func (el ScannerErrorList) Len() int { return len(el) }
+
+func (el ScannerErrorList) Swap(i, j int) { el[i], el[j] = el[j], el[i] }
+
+func (el ScannerErrorList) Less(i, j int) bool {
+	e := &el[i].Pos
+	f := &el[j].Pos
+
+	if e.Column != f.Column {
+		return e.Column < f.Column
+	}
+
+	return el[i].Msg < el[j].Msg
+}
+
+func (el ScannerErrorList) Sort() {
+	sort.Sort(el)
+}
+
+func (el ScannerErrorList) Error() string {
+	switch len(el) {
+	case 0:
+		return "no errors"
+	case 1:
+		return el[0].Error()
+	}
+	return fmt.Sprintf("%s (and %d more errors)", el[0], len(el)-1)
+}
+
+func (el ScannerErrorList) Err() error {
+	if len(el) == 0 {
+		return nil
+	}
+	return el
+}
+
+func PrintScannerError(w io.Writer, err error) {
+	if list, ok := err.(ScannerErrorList); ok {
+		for _, e := range list {
+			fmt.Fprintf(w, "%s\n", e)
+		}
+	} else if err != nil {
+		fmt.Fprintf(w, "%s\n", err)
+	}
+}
+
 func NewScanner(r io.Reader, cfg *ScannerConfig) *Scanner {
 	if cfg == nil {
 		cfg = DefaultScannerConfig
@@ -45,7 +115,7 @@ func NewScanner(r io.Reader, cfg *ScannerConfig) *Scanner {
 	}
 }
 
-func (s *Scanner) Scan() (Token, string, int) {
+func (s *Scanner) Scan() (Token, string, Pos) {
 	ch, pos := s.read()
 
 	if s.isBlankspace(ch) {
@@ -77,24 +147,24 @@ func (s *Scanner) Scan() (Token, string, int) {
 	return ILLEGAL, string(ch), pos
 }
 
-func (s *Scanner) read() (rune, int) {
+func (s *Scanner) read() (rune, Pos) {
 	ch, _, err := s.r.ReadRune()
 	s.i++
 
 	if errors.Is(err, io.EOF) {
-		return eol, s.i
+		return eol, Pos(s.i)
 	} else if err != nil {
 		log.Printf("unknown scanner error=%+v", err)
-		return eol, s.i
+		return eol, Pos(s.i)
 	}
 
-	return ch, s.i
+	return ch, Pos(s.i)
 }
 
-func (s *Scanner) unread() int {
+func (s *Scanner) unread() Pos {
 	_ = s.r.UnreadRune()
 	s.i--
-	return s.i
+	return Pos(s.i)
 }
 
 func (s *Scanner) isBlankspace(ch rune) bool {
@@ -117,7 +187,7 @@ func (s *Scanner) isAssignmentOperator(ch rune) bool {
 	return ch == s.cfg.AssignmentOperator
 }
 
-func (s *Scanner) scanBlankspace() (Token, string, int) {
+func (s *Scanner) scanBlankspace() (Token, string, Pos) {
 	buf := &bytes.Buffer{}
 	ch, pos := s.read()
 	buf.WriteRune(ch)
@@ -138,7 +208,7 @@ func (s *Scanner) scanBlankspace() (Token, string, int) {
 	return BS, buf.String(), pos
 }
 
-func (s *Scanner) scanArg() (Token, string, int) {
+func (s *Scanner) scanArg() (Token, string, Pos) {
 	buf := &bytes.Buffer{}
 	ch, pos := s.read()
 	buf.WriteRune(ch)

token.go

@@ -2,21 +2,49 @@
 
 package argh
 
+import "fmt"
+
 const (
 	ILLEGAL Token = iota
 	EOL
-	EMPTY
-	BS
-	IDENT
-	ARG_DELIMITER
-	COMMAND
-	ASSIGN
-	MULTI_VALUE_DELIMITER
-	LONG_FLAG
-	SHORT_FLAG
-	COMPOUND_SHORT_FLAG
-	STDIN_FLAG
-	STOP_FLAG
+	EMPTY                 // ''
+	BS                    // ' ' '\t' '\n'
+	IDENT                 // char group without flag prefix: 'some' 'words'
+	ARG_DELIMITER         // rune(0)
+	ASSIGN                // '='
+	MULTI_VALUE_DELIMITER // ','
+	LONG_FLAG             // char group with double flag prefix: '--flag'
+	SHORT_FLAG            // single char with single flag prefix: '-f'
+	COMPOUND_SHORT_FLAG   // char group with single flag prefix: '-flag'
+	STDIN_FLAG            // '-'
+	STOP_FLAG             // '--'
 )
 
 type Token int
+
+// Position is adapted from go/token.Position
+type Position struct {
+	Column int
+}
+
+func (p *Position) IsValid() bool { return p.Column > 0 }
+
+func (p Position) String() string {
+	s := ""
+	if p.IsValid() {
+		s = fmt.Sprintf("%d", p.Column)
+	}
+	if s == "" {
+		s = "-"
+	}
+	return s
+}
+
+// Pos is borrowed from go/token.Pos
+type Pos int
+
+const NoPos Pos = 0
+
+func (p Pos) IsValid() bool {
+	return p != NoPos
+}

token_string.go

@@ -14,19 +14,18 @@ func _() {
 	_ = x[BS-3]
 	_ = x[IDENT-4]
 	_ = x[ARG_DELIMITER-5]
-	_ = x[COMMAND-6]
-	_ = x[ASSIGN-7]
-	_ = x[MULTI_VALUE_DELIMITER-8]
-	_ = x[LONG_FLAG-9]
-	_ = x[SHORT_FLAG-10]
-	_ = x[COMPOUND_SHORT_FLAG-11]
-	_ = x[STDIN_FLAG-12]
-	_ = x[STOP_FLAG-13]
+	_ = x[ASSIGN-6]
+	_ = x[MULTI_VALUE_DELIMITER-7]
+	_ = x[LONG_FLAG-8]
+	_ = x[SHORT_FLAG-9]
+	_ = x[COMPOUND_SHORT_FLAG-10]
+	_ = x[STDIN_FLAG-11]
+	_ = x[STOP_FLAG-12]
 }
 
-const _Token_name = "ILLEGALEOLEMPTYBSIDENTARG_DELIMITERCOMMANDASSIGNMULTI_VALUE_DELIMITERLONG_FLAGSHORT_FLAGCOMPOUND_SHORT_FLAGSTDIN_FLAGSTOP_FLAG"
+const _Token_name = "ILLEGALEOLEMPTYBSIDENTARG_DELIMITERASSIGNMULTI_VALUE_DELIMITERLONG_FLAGSHORT_FLAGCOMPOUND_SHORT_FLAGSTDIN_FLAGSTOP_FLAG"
 
-var _Token_index = [...]uint8{0, 7, 10, 15, 17, 22, 35, 42, 48, 69, 78, 88, 107, 117, 126}
+var _Token_index = [...]uint8{0, 7, 10, 15, 17, 22, 35, 41, 62, 71, 81, 100, 110, 119}
 
 func (i Token) String() string {
 	if i < 0 || i >= Token(len(_Token_index)-1) {