fix bug with building empty items of sequences

check_test.go

@@ -43,27 +43,28 @@ func checkNode(t *testing.T, ignorePosition bool, left, right *Node) {
 		return
 	}
 
-	if len(left.Nodes) != len(right.Nodes) {
+	lnodes, rnodes := left.Nodes, right.Nodes
-		t.Error("length doesn't match", left.Name, len(left.Nodes), len(right.Nodes))
+	if len(lnodes) != len(rnodes) {
+		t.Error("length doesn't match", left.Name, len(lnodes), len(rnodes))
 		t.Log(left)
 		t.Log(right)
 		for {
-			if len(left.Nodes) > 0 {
+			if len(lnodes) > 0 {
-				t.Log("<", left.Nodes[0])
+				t.Log("<", lnodes[0])
-				left.Nodes = left.Nodes[1:]
+				lnodes = lnodes[1:]
 			}
 
-			if len(right.Nodes) > 0 {
+			if len(rnodes) > 0 {
-				t.Log(">", right.Nodes[0])
+				t.Log(">", rnodes[0])
-				right.Nodes = right.Nodes[1:]
+				rnodes = rnodes[1:]
 			}
 
-			if len(left.Nodes) == 0 && len(right.Nodes) == 0 {
+			if len(lnodes) == 0 && len(rnodes) == 0 {
 				break
 			}
 		}
 		return
 	}
 
-	checkNodes(t, ignorePosition, left.Nodes, right.Nodes)
+	checkNodes(t, ignorePosition, lnodes, rnodes)
 }

choice.go

@@ -50,12 +50,12 @@ func (d *choiceDefinition) validate(r *registry) error {
 
 	d.validated = true
 	for i := range d.options {
-		e, ok := r.definitions[d.options[i]]
+		o, ok := r.definitions[d.options[i]]
 		if !ok {
 			return parserNotFound(d.options[i])
 		}
 
-		if err := e.validate(r); err != nil {
+		if err := o.validate(r); err != nil {
 			return err
 		}
 	}
@@ -76,8 +76,8 @@ func (d *choiceDefinition) createBuilder() {
 }
 
 func (d *choiceDefinition) initOptions(r *registry) {
-	for _, e := range d.options {
+	for _, o := range d.options {
-		def := r.definitions[e]
+		def := r.definitions[o]
 		d.optionDefs = append(d.optionDefs, def)
 		def.init(r)
 		d.cbuilder.options = append(d.cbuilder.options, def.builder())
@@ -101,8 +101,8 @@ func (d *choiceDefinition) addGeneralization(g int) {
 	}
 
 	d.generalizations = append(d.generalizations, g)
-	for _, e := range d.optionDefs {
+	for _, o := range d.optionDefs {
-		e.addGeneralization(g)
+		o.addGeneralization(g)
 	}
 }
 
@@ -201,15 +201,25 @@ func (b *choiceBuilder) nodeName() string { return b.name }
 func (b *choiceBuilder) nodeID() int      { return b.id }
 
 func (b *choiceBuilder) build(c *context) ([]*Node, bool) {
-	to, ok := c.results.takeMatch(c.offset, b.id)
+	to, ok := c.results.longestMatch(c.offset, b.id)
 	if !ok {
 		return nil, false
 	}
 
+	if c.buildPending(c.offset, b.id, to) {
+		return nil, false
+	}
+
+	c.markBuildPending(c.offset, b.id, to)
+
+	if to-c.offset > 0 {
+		c.results.dropMatchTo(c.offset, b.id, to)
+	}
+
 	var option builder
-	for _, e := range b.options {
+	for _, o := range b.options {
-		if c.results.hasMatchTo(c.offset, e.nodeID(), to) {
+		if c.results.hasMatchTo(c.offset, o.nodeID(), to) {
-			option = e
+			option = o
 			break
 		}
 	}
@@ -225,6 +235,8 @@ func (b *choiceBuilder) build(c *context) ([]*Node, bool) {
 		panic("damaged parse result")
 	}
 
+	c.unmarkBuildPending(from, b.id, to)
+
 	if b.commit&Alias != 0 {
 		return n, true
 	}

context.go

@@ -63,7 +63,7 @@ func (c *context) token() (rune, bool) {
 	return c.tokens[c.offset], true
 }
 
-func (c *context) pending(offset int, id int) bool {
+func (c *context) pending(offset, id int) bool {
 	if len(c.isPending) <= id {
 		return false
 	}
@@ -77,7 +77,7 @@ func (c *context) pending(offset int, id int) bool {
 	return false
 }
 
-func (c *context) markPending(offset int, id int) {
+func (c *context) markPending(offset, id int) {
 	if len(c.isPending) <= id {
 		if cap(c.isPending) > id {
 			c.isPending = c.isPending[:id+1]
@@ -99,7 +99,7 @@ func (c *context) markPending(offset int, id int) {
 	c.isPending[id] = append(c.isPending[id], offset)
 }
 
-func (c *context) unmarkPending(offset int, id int) {
+func (c *context) unmarkPending(offset, id int) {
 	for i := range c.isPending[id] {
 		if c.isPending[id][i] == offset {
 			c.isPending[id][i] = -1
@@ -108,8 +108,58 @@ func (c *context) unmarkPending(offset int, id int) {
 	}
 }
 
+func (c *context) resetPending() {
+	c.isPending = nil
+}
+
+func (c *context) buildPending(offset, id, to int) bool {
+	if len(c.isPending) <= id {
+		return false
+	}
+
+	for i := 0; i < len(c.isPending[id]); i += 2 {
+		if c.isPending[id][i] == offset && c.isPending[id][i+1] == to {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (c *context) markBuildPending(offset, id, to int) {
+	if len(c.isPending) <= id {
+		if cap(c.isPending) > id {
+			c.isPending = c.isPending[:id+1]
+		} else {
+			c.isPending = c.isPending[:cap(c.isPending)]
+			for i := cap(c.isPending); i <= id; i++ {
+				c.isPending = append(c.isPending, nil)
+			}
+		}
+	}
+
+	for i := 0; i < len(c.isPending[id]); i += 2 {
+		if c.isPending[id][i] == -1 {
+			c.isPending[id][i] = offset
+			c.isPending[id][i+1] = to
+			return
+		}
+	}
+
+	c.isPending[id] = append(c.isPending[id], offset, to)
+}
+
+func (c *context) unmarkBuildPending(offset, id, to int) {
+	for i := 0; i < len(c.isPending[id]); i += 2 {
+		if c.isPending[id][i] == offset && c.isPending[id][i+1] == to {
+			c.isPending[id][i] = -1
+			break
+		}
+	}
+}
+
 func (c *context) fromResults(id int) bool {
-	to, m, ok := c.results.getMatch(c.offset, id)
+	to, m, ok := c.results.longestResult(c.offset, id)
 	if !ok {
 		return false
 	}
@@ -138,7 +188,7 @@ func (c *context) finalizeParse(rootID int) error {
 		return ErrInvalidInput
 	}
 
-	to, match, found := c.results.getMatch(0, rootID)
+	to, match, found := c.results.longestResult(0, rootID)
 	if !found || !match || to < c.readOffset {
 		return ErrUnexpectedCharacter
 	}

node.go

@@ -83,8 +83,14 @@ func (n *Node) commit(t []rune) {
 }
 
 func (n *Node) String() string {
-	if n.From >= len(n.tokens) || n.To > len(n.tokens) {
+	if n.From >= len(n.tokens) && n.To != n.From || n.To > len(n.tokens) {
-		return n.Name + ":invalid"
+		return fmt.Sprintf(
+			"%s:invalid:%d:%d:%d",
+			n.Name,
+			len(n.tokens),
+			n.From,
+			n.To,
+		)
 	}
 
 	return fmt.Sprintf("%s:%d:%d:%s", n.Name, n.From, n.To, n.Text())

parse_test.go

@@ -133,6 +133,34 @@ func TestRecursion(t *testing.T) {
 			},
 		}},
 	)
+
+	runTests(
+		t,
+		`A = "a" | A*`,
+		[]testItem{{
+			title:          "recursive sequence in choice",
+			text:           "aaaa",
+			ignorePosition: true,
+			node: &Node{
+				Name: "A",
+				Nodes: []*Node{{
+					Name: "A",
+				}, {
+					Name: "A",
+					Nodes: []*Node{{
+						Name: "A",
+					}, {
+						Name: "A",
+						Nodes: []*Node{{
+							Name: "A",
+						}, {
+							Name: "A",
+						}},
+					}},
+				}},
+			},
+		}},
+	)
 }
 
 func TestSequence(t *testing.T) {
@@ -188,33 +216,24 @@ func TestSequence(t *testing.T) {
 			},
 		}},
 	)
-}
 
-func TestSequenceBug(t *testing.T) {
 	runTests(
 		t,
-		`A = "a" | A*`,
+		`a = "a"?; A = a | a*`,
 		[]testItem{{
-			title: "BUG: recursive sequence in choice",
+			title:          "single or zero-or-more optional in choice",
 			text:           "aaa",
+			ignorePosition: true,
 			node: &Node{
 				Name: "A",
 				Nodes: []*Node{{
-					Name: "A",
+					Name: "a",
 				}, {
-					Name: "A",
+					Name: "a",
-					Nodes: []*Node{{
-						Name: "A",
 				}, {
-						Name: "A",
+					Name: "a",
-					}, {
-						Name: "A",
-					}},
-				}, {
-					Name: "A",
 				}},
 			},
-			ignorePosition: true,
 		}},
 	)
 }
@@ -571,12 +590,14 @@ func TestUndefined(t *testing.T) {
 	n, err := s.Parse(bytes.NewBufferString("a = b"))
 	if err != nil {
 		t.Error(err)
+		return
 	}
 
 	stest := &Syntax{}
 	err = define(stest, n)
 	if err != nil {
 		t.Error(err)
+		return
 	}
 
 	if err := stest.Init(); err == nil {
@@ -628,6 +649,22 @@ func TestEmpty(t *testing.T) {
 			},
 		}},
 	)
+
+	runTests(
+		t,
+		`a = [a]*; a':alias = a; a'' = a' [^a]*`,
+		[]testItem{{
+			title:          "no a",
+			text:           "b",
+			ignorePosition: true,
+			node: &Node{
+				Name: "a''",
+				Nodes: []*Node{{
+					Name: "a",
+				}},
+			},
+		}},
+	)
 }
 
 func TestCharAsRoot(t *testing.T) {

results.go

@@ -5,49 +5,75 @@ type results struct {
 	match   [][]int
 }
 
-func (s *results) getMatch(offset, id int) (int, bool, bool) {
+func (r *results) ensureOffset(offset int) {
-	if len(s.noMatch) > offset && s.noMatch[offset] != nil && s.noMatch[offset].has(id) {
+	if len(r.match) > offset {
-		return 0, false, true
+		return
 	}
 
-	if len(s.match) <= offset {
+	if cap(r.match) > offset {
-		return 0, false, false
+		r.match = r.match[:offset+1]
+		return
 	}
 
-	var (
+	r.match = r.match[:cap(r.match)]
-		found bool
+	for i := len(r.match); i <= offset; i++ {
-		to    int
+		r.match = append(r.match, nil)
-	)
-
-	for i := 0; i < len(s.match[offset]); i += 2 {
-		if s.match[offset][i] != id {
-			continue
 	}
-
-		found = true
-		if s.match[offset][i+1] > to {
-			to = s.match[offset][i+1]
-		}
-	}
-
-	return to, found, found
 }
 
-func (s *results) hasMatchTo(offset, id, to int) bool {
+func (r *results) setMatch(offset, id, to int) {
-	if len(s.noMatch) > offset && s.noMatch[offset] != nil && s.noMatch[offset].has(id) {
+	r.ensureOffset(offset)
-		return false
+	for i := 0; i < len(r.match[offset]); i += 2 {
-	}
+		if r.match[offset][i] != id || r.match[offset][i+1] != to {
-
-	if len(s.match) <= offset {
-		return false
-	}
-
-	for i := 0; i < len(s.match[offset]); i += 2 {
-		if s.match[offset][i] != id {
 			continue
 		}
 
-		if s.match[offset][i+1] == to {
+		return
+	}
+
+	r.match[offset] = append(r.match[offset], id, to)
+}
+
+func (r *results) setNoMatch(offset, id int) {
+	if len(r.match) > offset {
+		for i := 0; i < len(r.match[offset]); i += 2 {
+			if r.match[offset][i] != id {
+				continue
+			}
+
+			return
+		}
+	}
+
+	if len(r.noMatch) <= offset {
+		if cap(r.noMatch) > offset {
+			r.noMatch = r.noMatch[:offset+1]
+		} else {
+			r.noMatch = r.noMatch[:cap(r.noMatch)]
+			for i := cap(r.noMatch); i <= offset; i++ {
+				r.noMatch = append(r.noMatch, nil)
+			}
+		}
+	}
+
+	if r.noMatch[offset] == nil {
+		r.noMatch[offset] = &idSet{}
+	}
+
+	r.noMatch[offset].set(id)
+}
+
+func (r *results) hasMatchTo(offset, id, to int) bool {
+	if len(r.match) <= offset {
+		return false
+	}
+
+	for i := 0; i < len(r.match[offset]); i += 2 {
+		if r.match[offset][i] != id {
+			continue
+		}
+
+		if r.match[offset][i+1] == to {
 			return true
 		}
 	}
@@ -55,91 +81,46 @@ func (s *results) hasMatchTo(offset, id, to int) bool {
 	return false
 }
 
-func (s *results) takeMatch(offset, id int) (int, bool) {
+func (r *results) longestMatch(offset, id int) (int, bool) {
-	if len(s.match) <= offset {
+	if len(r.match) <= offset {
 		return 0, false
 	}
 
-	var (
+	var found bool
-		found bool
+	to := -1
-		to    int
+	for i := 0; i < len(r.match[offset]); i += 2 {
-		index int
+		if r.match[offset][i] != id {
-	)
-
-	for i := 0; i < len(s.match[offset]); i += 2 {
-		if s.match[offset][i] != id {
 			continue
 		}
 
-		if s.match[offset][i+1] > to || !found {
+		if r.match[offset][i+1] > to {
-			to = s.match[offset][i+1]
+			to = r.match[offset][i+1]
-			index = i
 		}
 
 		found = true
 	}
 
-	if found && to-offset > 0 {
-		s.match[offset][index] = -1
-	}
-
 	return to, found
 }
 
-func (s *results) ensureOffset(offset int) {
+func (r *results) longestResult(offset, id int) (int, bool, bool) {
-	if len(s.match) > offset {
+	if len(r.noMatch) > offset && r.noMatch[offset] != nil && r.noMatch[offset].has(id) {
-		return
+		return 0, false, true
 	}
 
-	if cap(s.match) > offset {
+	to, ok := r.longestMatch(offset, id)
-		s.match = s.match[:offset+1]
+	return to, ok, ok
-		return
-	}
-
-	s.match = s.match[:cap(s.match)]
-	for i := len(s.match); i <= offset; i++ {
-		s.match = append(s.match, nil)
-	}
 }
 
-func (s *results) setMatch(offset, id, to int) {
+func (r *results) dropMatchTo(offset, id, to int) {
-	s.ensureOffset(offset)
+	for i := 0; i < len(r.match[offset]); i += 2 {
-	for i := 0; i < len(s.match[offset]); i += 2 {
+		if r.match[offset][i] != id {
-		if s.match[offset][i] != id || s.match[offset][i+1] != to {
-			continue
-		}
-
-		return
-	}
-
-	s.match[offset] = append(s.match[offset], id, to)
-}
-
-func (s *results) setNoMatch(offset, id int) {
-	if len(s.match) > offset {
-		for i := 0; i < len(s.match[offset]); i += 2 {
-			if s.match[offset][i] != id {
 			continue
 		}
 
+		if r.match[offset][i+1] == to {
+			r.match[offset][i] = -1
 			return
 		}
 	}
-
-	if len(s.noMatch) <= offset {
-		if cap(s.noMatch) > offset {
-			s.noMatch = s.noMatch[:offset+1]
-		} else {
-			s.noMatch = s.noMatch[:cap(s.noMatch)]
-			for i := cap(s.noMatch); i <= offset; i++ {
-				s.noMatch = append(s.noMatch, nil)
-			}
-		}
-	}
-
-	if s.noMatch[offset] == nil {
-		s.noMatch[offset] = &idSet{}
-	}
-
-	s.noMatch[offset].set(id)
 }

run_test.go

@@ -15,9 +15,18 @@ type testItem struct {
 	ignorePosition bool
 }
 
-func runTestsSyntax(t *testing.T, s *Syntax, tests []testItem) {
+func runTestsGetSyntax(t *testing.T, getSyntax func(t *testing.T) *Syntax, tests []testItem) {
+	var s *Syntax
 	for _, test := range tests {
 		t.Run(test.title, func(t *testing.T) {
+			if s == nil {
+				s = getSyntax(t)
+			}
+
+			if t.Failed() {
+				return
+			}
+
 			b := bytes.NewBufferString(test.text)
 
 			start := time.Now()
@@ -43,22 +52,32 @@ func runTestsSyntax(t *testing.T, s *Syntax, tests []testItem) {
 	}
 }
 
+func runTestsSyntax(t *testing.T, s *Syntax, tests []testItem) {
+	runTestsGetSyntax(t, func(*testing.T) *Syntax { return s }, tests)
+}
+
 func runTests(t *testing.T, syntax string, tests []testItem) {
+	getSyntax := func(t *testing.T) *Syntax {
 		s, err := openSyntaxString(syntax)
 		if err != nil {
 			t.Error(err)
-		return
 		}
 
-	runTestsSyntax(t, s, tests)
+		return s
+	}
+
+	runTestsGetSyntax(t, getSyntax, tests)
 }
 
 func runTestsFile(t *testing.T, file string, tests []testItem) {
+	getSyntax := func(t *testing.T) *Syntax {
 		s, err := openSyntaxFile(file)
 		if err != nil {
 			t.Error(err)
-		return
 		}
 
-	runTestsSyntax(t, s, tests)
+		return s
+	}
+
+	runTestsGetSyntax(t, getSyntax, tests)
 }

sequence.go

@@ -184,6 +184,8 @@ func (p *sequenceParser) parse(c *context) {
 		// TODO:
 		// - is it ok to parse before max range check? what if max=0
 		// - validate, normalize and document max=0
+
+		// TODO: test this f(g())
 		p.items[itemIndex].parse(c)
 		if !c.matchLast {
 			if currentCount < p.ranges[itemIndex][0] {
@@ -232,18 +234,27 @@ func (b *sequenceBuilder) nodeName() string { return b.name }
 func (b *sequenceBuilder) nodeID() int      { return b.id }
 
 func (b *sequenceBuilder) build(c *context) ([]*Node, bool) {
-	to, ok := c.results.takeMatch(c.offset, b.id)
+	to, ok := c.results.longestMatch(c.offset, b.id)
 	if !ok {
 		return nil, false
 	}
 
-	if to-c.offset == 0 && b.commit&Alias != 0 {
+	if c.buildPending(c.offset, b.id, to) {
-		return nil, true
+		return nil, false
+	}
+
+	c.markBuildPending(c.offset, b.id, to)
+
+	if to-c.offset > 0 {
+		c.results.dropMatchTo(c.offset, b.id, to)
 	}
 
-	if b.allChars {
 	from := c.offset
+
+	if b.allChars {
 		c.offset = to
+		c.unmarkBuildPending(from, b.id, to)
+
 		if b.commit&Alias != 0 {
 			return nil, true
 		}
@@ -256,7 +267,6 @@ func (b *sequenceBuilder) build(c *context) ([]*Node, bool) {
 		}}, true
 	}
 
-	from := c.offset
 	var (
 		itemIndex    int
 		currentCount int
@@ -277,17 +287,32 @@ func (b *sequenceBuilder) build(c *context) ([]*Node, bool) {
 		}
 
 		parsed := c.offset > itemFrom
-		if parsed || len(n) > 0 {
+
+		if parsed {
 			nodes = append(nodes, n...)
 			currentCount++
 		}
 
-		if !parsed || b.ranges[itemIndex][1] >= 0 && currentCount == b.ranges[itemIndex][1] {
+		if !parsed {
+			if currentCount < b.ranges[itemIndex][0] {
+				for i := 0; i < b.ranges[itemIndex][0]-currentCount; i++ {
+					nodes = append(nodes, n...)
+				}
+			}
+
+			itemIndex++
+			currentCount = 0
+			continue
+		}
+
+		if b.ranges[itemIndex][1] >= 0 && currentCount == b.ranges[itemIndex][1] {
 			itemIndex++
 			currentCount = 0
 		}
 	}
 
+	c.unmarkBuildPending(from, b.id, to)
+
 	if b.commit&Alias != 0 {
 		return nodes, true
 	}

syntax.go

@@ -318,6 +318,8 @@ func (s *Syntax) Parse(r io.Reader) (*Node, error) {
 	}
 
 	c.offset = 0
+	c.resetPending()
+
 	n, ok := s.builder.build(c)
 	if !ok || len(n) != 1 {
 		panic("damaged parse result")

whitespace.go

@@ -66,6 +66,7 @@ func applyWhitespaceToSeq(s *sequenceDefinition) []definition {
 
 	whitespace := SequenceItem{Name: whitespaceName, Min: 0, Max: -1}
 	for i, item := range s.items {
+		// TODO: there should not be max=0
 		if item.Max >= 0 && item.Max <= 1 {
 			if i > 0 {
 				items = append(items, whitespace)
@@ -98,8 +99,13 @@ func applyWhitespaceToSeq(s *sequenceDefinition) []definition {
 			continue
 		}
 
+		optItems := []SequenceItem{singleItem, restItems}
+		if i > 0 {
+			optItems = []SequenceItem{whitespace, singleItem, restItems}
+		}
+
 		optName := patchName(item.Name, s.nodeName(), "wsopt", strconv.Itoa(i))
-		optDef := newSequence(optName, Alias, []SequenceItem{whitespace, singleItem, restItems})
+		optDef := newSequence(optName, Alias, optItems)
 		defs = append(defs, optDef)
 		items = append(items, SequenceItem{Name: optName, Min: 0, Max: 1})
 	}

whitespace_test.go

@@ -8,9 +8,9 @@ const (
 		word-char:alias = [^\n, \t];
 		cell            = (word-char (ws* word-char)*)?;
 		rest-cell:alias = "," ws* cell;
-		line            = cell ws* (rest-cell (ws* rest-cell)*)?;
+		line            = cell (ws* rest-cell (ws* rest-cell)*)?;
 		rest-line:alias = "\n" ws* line;
-		document        = ws* (line ws* (rest-line (ws* rest-line)*)?)? ws*;
+		document        = ws* (line (ws* rest-line (ws* rest-line)*)?)? ws*;
 	`
 
 	csvWithWhitespaceSupport = `
@@ -24,6 +24,7 @@ const (
 func TestCSVWhitespace(t *testing.T) {
 	tests := []testItem{{
 		title:          "empty",
+		ignorePosition: true,
 		node: &Node{
 			Name: "document",
 		},