[dev.typeparams] cmd/compile/internal/syntax: clean up node printing API

Preparation for using the syntax printer as expression printer in types2.

- Introduced Form to control printing format
- Cleaned up/added String and ShortString convenience functions
- Implemented ShortForm format which prints … for non-empty
  function and composite literal bodies
- Added test to check write error handling

Change-Id: Ie86e46d766fb60fcf07ef643c7788b2ef440ffa8
Reviewed-on: https://go-review.googlesource.com/c/go/+/282552
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/cmd/compile/internal/syntax/parser_test.go b/src/cmd/compile/internal/syntax/parser_test.go
index ea9e9acc83..340ca6bb6f 100644
--- a/src/cmd/compile/internal/syntax/parser_test.go
+++ b/src/cmd/compile/internal/syntax/parser_test.go
@@ -169,7 +169,7 @@ func walkDirs(t *testing.T, dir string, action func(string)) {
 
 func verifyPrint(t *testing.T, filename string, ast1 *File) {
 	var buf1 bytes.Buffer
-	_, err := Fprint(&buf1, ast1, true)
+	_, err := Fprint(&buf1, ast1, LineForm)
 	if err != nil {
 		panic(err)
 	}
@@ -181,7 +181,7 @@ func verifyPrint(t *testing.T, filename string, ast1 *File) {
 	}
 
 	var buf2 bytes.Buffer
-	_, err = Fprint(&buf2, ast2, true)
+	_, err = Fprint(&buf2, ast2, LineForm)
 	if err != nil {
 		panic(err)
 	}