parse scenario or background steps

gherkin/ast.go

@@ -0,0 +1,59 @@
+package gherkin
+
+import (
+	"sync"
+
+	"github.com/l3pp4rd/behat/gherkin/lexer"
+)
+
+type item struct {
+	next, prev *item
+	value      *lexer.Token
+}
+
+type AST struct {
+	head, tail *item
+	mut        *sync.Mutex
+}
+
+func newAST() *AST {
+	return &AST{mut: &sync.Mutex{}}
+}
+
+func (l *AST) addTail(t *lexer.Token) *item {
+	l.mut.Lock()
+	defer l.mut.Unlock()
+
+	it := &item{next: nil, prev: l.tail, value: t}
+	if l.head == nil {
+		l.head = it
+	} else {
+		l.tail.next = it
+	}
+	l.tail = it
+	return l.tail
+}
+
+func (l *AST) addBefore(t *lexer.Token, i *item) *item {
+	l.mut.Lock()
+	defer l.mut.Unlock()
+
+	it := &item{next: i, prev: i.prev, value: t}
+	i.prev = it
+	if it.prev == nil {
+		l.head = it
+	}
+	return it
+}
+
+func (l *AST) addAfter(t *lexer.Token, i *item) *item {
+	l.mut.Lock()
+	defer l.mut.Unlock()
+
+	it := &item{next: i.next, prev: i, value: t}
+	i.next = it
+	if it.next == nil {
+		l.tail = it
+	}
+	return it
+}

gherkin/lexer/token_type.go

@@ -20,6 +20,8 @@ const (
 	FEATURE
 	BACKGROUND
 	SCENARIO
+
+	steps
 	GIVEN
 	WHEN
 	THEN

gherkin/parse.go

@@ -2,7 +2,8 @@ package gherkin
 
 import (
 	"errors"
-	"io"
+	"fmt"
+	"os"
 	"strings"
 
 	"github.com/l3pp4rd/behat/gherkin/lexer"
@@ -11,6 +12,7 @@ import (
 type Tag string
 
 type Scenario struct {
+	Title string
 	Steps []*Step
 	Tags  []Tag
 }
@@ -40,64 +42,148 @@ type Feature struct {
 	Scenarios   []*Scenario
 }
 
-var ErrNotFeature = errors.New("expected a file to begin with a feature definition")
+var steps = []lexer.TokenType{
+	lexer.GIVEN,
+	lexer.WHEN,
+	lexer.THEN,
+	lexer.AND,
+	lexer.BUT,
+}
+
 var ErrEmpty = errors.New("the feature file is empty")
-var ErrTagsNextToFeature = errors.New("tags must be a single line next to a feature definition")
-var ErrSingleBackground = errors.New("there can only be a single background section")
 
 type parser struct {
 	lx   *lexer.Lexer
+	path string
+	ast  *AST
 }
 
-func Parse(r io.Reader) (*Feature, error) {
-	return (parser{lx: lexer.New(r)}).parseFeature()
+func Parse(path string) (*Feature, error) {
+	file, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	return (&parser{
+		lx:   lexer.New(file),
+		path: path,
+		ast:  newAST(),
+	}).parseFeature()
 }
 
-func (p parser) parseFeature() (*Feature, error) {
-	var tok *lexer.Token = p.lx.Next(lexer.COMMENT, lexer.NEW_LINE)
+// reads tokens into AST and skips comments or new lines
+func (p *parser) next() *lexer.Token {
+	tok := p.lx.Next()
+	p.ast.addTail(tok)
+	if tok.OfType(lexer.COMMENT, lexer.NEW_LINE) {
+		return p.next()
+	}
+	return tok
+}
+
+// peaks into next token, skips comments or new lines
+func (p *parser) peek() *lexer.Token {
+	if tok := p.lx.Peek(); tok.OfType(lexer.COMMENT, lexer.NEW_LINE) {
+		p.lx.Next()
+	}
+	return p.peek()
+}
+
+func (p *parser) err(s string, l int) error {
+	return fmt.Errorf("%s on %s:%d", s, p.path, l)
+}
+
+func (p *parser) parseFeature() (*Feature, error) {
+	var tok *lexer.Token = p.next()
 	if tok.Type == lexer.EOF {
 		return nil, ErrEmpty
 	}
 
 	ft := &Feature{}
 	if tok.Type == lexer.TAGS {
-		if p.lx.Peek().Type != lexer.FEATURE {
-			return ft, ErrTagsNextToFeature
+		if p.peek().Type != lexer.FEATURE {
+			return ft, p.err("tags must be a single line next to a feature definition", tok.Line)
 		}
 		ft.Tags = p.parseTags(tok.Value)
-		tok = p.lx.Next()
+		tok = p.next()
 	}
 
 	if tok.Type != lexer.FEATURE {
-		return ft, ErrNotFeature
+		return ft, p.err("expected a file to begin with a feature definition, but got '"+tok.Type.String()+"' instead", tok.Line)
 	}
 
 	ft.Title = tok.Value
 	var desc []string
-	for ; p.lx.Peek().Type == lexer.TEXT; tok = p.lx.Next() {
+	for ; p.peek().Type == lexer.TEXT; tok = p.next() {
 		desc = append(desc, tok.Value)
 	}
 	ft.Description = strings.Join(desc, "\n")
 
-	tok = p.lx.Next(lexer.COMMENT, lexer.NEW_LINE)
-	for ; tok.Type != lexer.EOF; p.lx.Next(lexer.COMMENT, lexer.NEW_LINE) {
+	tok = p.next()
+	for tok = p.next(); tok.Type != lexer.EOF; p.next() {
+		// there may be a background
 		if tok.Type == lexer.BACKGROUND {
 			if ft.Background != nil {
-				return ft, ErrSingleBackground
+				return ft, p.err("there can only be a single background section, but found another", tok.Line)
 			}
 			ft.Background = p.parseBackground()
 			continue
 		}
+		// there may be tags before scenario
+		sc := &Scenario{}
+		if tok.Type == lexer.TAGS {
+			sc.Tags, tok = p.parseTags(tok.Value), p.next()
+		}
+
+		// there must be a scenario otherwise
+		if tok.Type != lexer.SCENARIO {
+			return ft, p.err("expected a scenario, but got '"+tok.Type.String()+"' instead", tok.Line)
+		}
+
+		sc.Title = tok.Value
+		p.parseSteps(sc)
+		ft.Scenarios = append(ft.Scenarios, sc)
 	}
 
 	return ft, nil
 }
 
-func (p parser) parseBackground() *Background {
+func (p *parser) parseBackground() *Background {
 	return nil
 }
 
-func (p parser) parseTags(s string) (tags []Tag) {
+func (p *parser) parseSteps(s *Scenario) error {
+	var tok *lexer.Token
+	for ; p.peek().OfType(steps...); tok = p.next() {
+		step := &Step{Text: tok.Value}
+		switch tok.Type {
+		case lexer.GIVEN:
+			step.Type = Given
+		case lexer.WHEN:
+			step.Type = When
+		case lexer.THEN:
+			step.Type = Then
+		case lexer.AND:
+		case lexer.BUT:
+			if len(s.Steps) > 0 {
+				step.Type = s.Steps[len(s.Steps)-1].Type
+			} else {
+				step.Type = Given
+			}
+		}
+		for ; p.peek().OfType(lexer.TEXT); tok = p.next() {
+			step.Text += " " + tok.Value
+		}
+		// now look for pystring or table
+
+		s.Steps = append(s.Steps, step)
+		// return fmt.Errorf("A step was expected, but got: '%s' instead on %s:%d", tok.Type, "file", tok.Line)
+	}
+	return nil
+}
+
+func (p *parser) parseTags(s string) (tags []Tag) {
 	for _, tag := range strings.Split(s, " ") {
 		t := strings.Trim(tag, "@ ")
 		if len(t) > 0 {