gc: improved syntax errors

* example-based syntax errors (go.errors)

* enable bison's more specific errors
  and translate grammar token names into
  tokens like ++

* test cases

R=ken2, r, ken3
CC=golang-dev
http://codereview.appspot.com/194085

11 files changed, 143 insertions, 0 deletions

diff --git a/test/syntax/forvar.go b/test/syntax/forvar.go
new file mode 100644
index 000000000..f12ce55ca
--- /dev/null
+++ b/test/syntax/forvar.go
@@ -0,0 +1,10 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func main() {
+	for var x = 0; x < 10; x++ {	// ERROR "var declaration not allowed in for initializer"
diff --git a/test/syntax/import.go b/test/syntax/import.go
new file mode 100644
index 000000000..90e7df007
--- /dev/null
+++ b/test/syntax/import.go
@@ -0,0 +1,14 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"io",	// ERROR "unexpected ,"
+	"os"
+)
+
+
diff --git a/test/syntax/interface.go b/test/syntax/interface.go
new file mode 100644
index 000000000..a7f43533a
--- /dev/null
+++ b/test/syntax/interface.go
@@ -0,0 +1,14 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+type T interface {
+	f, g ()	// ERROR "name list not allowed in interface type"
+}
+
+
+
diff --git a/test/syntax/semi1.go b/test/syntax/semi1.go
new file mode 100644
index 000000000..c805bb006
--- /dev/null
+++ b/test/syntax/semi1.go
@@ -0,0 +1,14 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func main() {
+	if x; y	// ERROR "unexpected ; or newline before {"
+	{
+		z
+
+
diff --git a/test/syntax/semi2.go b/test/syntax/semi2.go
new file mode 100644
index 000000000..237fac8f3
--- /dev/null
+++ b/test/syntax/semi2.go
@@ -0,0 +1,14 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func main() {
+	switch x; y	// ERROR "unexpected ; or newline before {"
+	{
+		z
+
+
diff --git a/test/syntax/semi3.go b/test/syntax/semi3.go
new file mode 100644
index 000000000..2dbcb5984
--- /dev/null
+++ b/test/syntax/semi3.go
@@ -0,0 +1,14 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func main() {
+	for x; y; z	// ERROR "unexpected ; or newline before {"
+	{
+		z
+
+
diff --git a/test/syntax/semi4.go b/test/syntax/semi4.go
new file mode 100644
index 000000000..2268cf75a
--- /dev/null
+++ b/test/syntax/semi4.go
@@ -0,0 +1,14 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func main() {
+	for x
+	{	// ERROR "unexpected ; or newline before {"
+		z
+
+
diff --git a/test/syntax/semi5.go b/test/syntax/semi5.go
new file mode 100644
index 000000000..7f907fb8f
--- /dev/null
+++ b/test/syntax/semi5.go
@@ -0,0 +1,13 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func main()
+{	// ERROR "unexpected ; or newline before {"
+
+
+
diff --git a/test/syntax/semi6.go b/test/syntax/semi6.go
new file mode 100644
index 000000000..75de3e0a1
--- /dev/null
+++ b/test/syntax/semi6.go
@@ -0,0 +1,13 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+type T	// ERROR "unexpected ; or newline in type declaration"
+{
+
+
+
diff --git a/test/syntax/semi7.go b/test/syntax/semi7.go
new file mode 100644
index 000000000..458904357
--- /dev/null
+++ b/test/syntax/semi7.go
@@ -0,0 +1,14 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func main() {
+	if x { }
+	else { }	// ERROR "unexpected ; or newline before else"
+}
+
+
diff --git a/test/syntax/slice.go b/test/syntax/slice.go
new file mode 100644
index 000000000..4bc5d4d8d
--- /dev/null
+++ b/test/syntax/slice.go
@@ -0,0 +1,9 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+var x = y[:z]	// ERROR "missing lower bound in slice expression"