fix: ecma ranges with set terminator

Fix ECMAScript un-escaped literal '-' when followed predefined
character sets.

Also:
* Fixed missing error check on parseProperty() call.
* Use addChar(ch) helper instead of addRange(ch, ch).

Fixes #54

Author: stevenh

go.mod

@@ -1,3 +1,5 @@
 module github.com/dlclark/regexp2
 
 go 1.13
+
+require github.com/stretchr/testify v1.8.1

go.sum

@@ -0,0 +1,17 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

regexp_ecma_test.go

@@ -0,0 +1,50 @@
+package regexp2_test
+
+import (
+	"testing"
+
+	"github.com/dlclark/regexp2"
+	"github.com/stretchr/testify/require"
+)
+
+func TestECMA_basic(t *testing.T) {
+	tests := map[string]struct {
+		expr string
+		data string
+		want []string
+	}{
+		"charset": {
+			expr: `[a-c]`,
+			data: "abcd",
+			want: []string{"a", "b", "c"},
+		},
+		"charset-set": {
+			expr: `[a-\s]`,
+			data: "a-b cd",
+			want: []string{"a", "-", " "},
+		},
+	}
+
+	for name, tt := range tests {
+		t.Run(name, func(t *testing.T) {
+			re, err := regexp2.Compile(tt.expr, regexp2.ECMAScript)
+			require.NoError(t, err)
+
+			match, err := re.FindStringMatch(tt.data)
+			require.NoError(t, err)
+
+			var res []string
+			for match != nil {
+				for _, g := range match.Groups() {
+					for _, c := range g.Captures {
+						res = append(res, c.String())
+					}
+				}
+
+				match, err = re.FindNextMatch(match)
+				require.NoError(t, err)
+			}
+			require.Equal(t, tt.want, res)
+		})
+	}
+}

syntax/parser.go

@@ -1427,7 +1427,7 @@ func (p *parser) scanCapname() string {
 	return string(p.pattern[startpos:p.textpos()])
 }
 
-//Scans contents of [] (not including []'s), and converts to a set.
+// Scans contents of [] (not including []'s), and converts to a set.
 func (p *parser) scanCharSet(caseInsensitive, scanOnly bool) (*CharSet, error) {
 	ch := '\x00'
 	chPrev := '\x00'
@@ -1467,7 +1467,11 @@ func (p *parser) scanCharSet(caseInsensitive, scanOnly bool) (*CharSet, error) {
 			case 'D', 'd':
 				if !scanOnly {
 					if inRange {
-						return nil, p.getErr(ErrBadClassInCharRange, ch)
+						if !p.useOptionE() {
+							return nil, p.getErr(ErrBadClassInCharRange, ch)
+						}
+						cc.addChar('-')
+						cc.addChar(chPrev)
 					}
 					cc.addDigit(p.useOptionE() || p.useRE2(), ch == 'D', p.patternRaw)
 				}
@@ -1476,7 +1480,11 @@ func (p *parser) scanCharSet(caseInsensitive, scanOnly bool) (*CharSet, error) {
 			case 'S', 's':
 				if !scanOnly {
 					if inRange {
-						return nil, p.getErr(ErrBadClassInCharRange, ch)
+						if !p.useOptionE() {
+							return nil, p.getErr(ErrBadClassInCharRange, ch)
+						}
+						cc.addChar('-')
+						cc.addChar(chPrev)
 					}
 					cc.addSpace(p.useOptionE(), p.useRE2(), ch == 'S')
 				}
@@ -1485,7 +1493,11 @@ func (p *parser) scanCharSet(caseInsensitive, scanOnly bool) (*CharSet, error) {
 			case 'W', 'w':
 				if !scanOnly {
 					if inRange {
-						return nil, p.getErr(ErrBadClassInCharRange, ch)
+						if !p.useOptionE() {
+							return nil, p.getErr(ErrBadClassInCharRange, ch)
+						}
+						cc.addChar('-')
+						cc.addChar(chPrev)
 					}
 
 					cc.addWord(p.useOptionE() || p.useRE2(), ch == 'W')
@@ -1495,22 +1507,29 @@ func (p *parser) scanCharSet(caseInsensitive, scanOnly bool) (*CharSet, error) {
 			case 'p', 'P':
 				if !scanOnly {
 					if inRange {
-						return nil, p.getErr(ErrBadClassInCharRange, ch)
+						if !p.useOptionE() {
+							return nil, p.getErr(ErrBadClassInCharRange, ch)
+						}
+						cc.addChar('-')
+						cc.addChar(chPrev)
 					}
 					prop, err := p.parseProperty()
 					if err != nil {
 						return nil, err
 					}
 					cc.addCategory(prop, (ch != 'p'), caseInsensitive, p.patternRaw)
 				} else {
-					p.parseProperty()
+					_, err := p.parseProperty()
+					if err != nil {
+						return nil, err
+					}
 				}
 
 				continue
 
 			case '-':
 				if !scanOnly {
-					cc.addRange(ch, ch)
+					cc.addChar(ch)
 				}
 				continue