design/51082-godocfmt: add Printer fields for Text output

These are needed to provide the old go/doc API faithfully.

For golang/go#51082.

Change-Id: I975551873fdfd5fccae51280300bff14f2059aee
Reviewed-on: https://go-review.googlesource.com/c/proposal/+/398535
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/design/51082-godocfmt.md b/design/51082-godocfmt.md
index d2509df..d6841d8 100644
--- a/design/51082-godocfmt.md
+++ b/design/51082-godocfmt.md
@@ -939,6 +939,23 @@ type Printer struct {
 	// passed to [DocLink.DefaultURL] to construct a DocLink's URL.
 	// See that method's documentation for details.
 	DocLinkBaseURL string
+
+	// TextPrefix is a prefix to print at the start of every line
+	// when generating text output using the Text method.
+	TextPrefix string
+
+	// TextCodePrefix is the prefix to print at the start of each
+	// preformatted (code block) line when generating text output,
+	// instead of (not in addition to) TextPrefix.
+	// If TextCodePrefix is the empty string, it defaults to TextPrefix+"\t".
+	TextCodePrefix string
+
+	// TextWidth is the maximum width text line to generate,
+	// measured in Unicode code points,
+	// excluding TextPrefix and the newline character.
+	// If TextWidth is zero, it defaults to 80 minus the number of code points in TextPrefix.
+	// If TextWidth is negative, there is no limit.
+	TextWidth int
 }
     A Printer is a doc comment printer. The fields in the struct can be filled
     in before calling any of the printing methods in order to customize the