cmd/doc: truncate long lists of arguments

Some field-lists (especially in generated code) can be excessively long.
In the one-line printout, it does not make sense to print all elements
of the list if line-wrapping causes the "one-line" to become multi-line.

// Before:
var LongLine = newLongLine("someArgument1", "someArgument2", "someArgument3", "someArgument4", "someArgument5", "someArgument6", "someArgument7", "someArgument8")

// After:
var LongLine = newLongLine("someArgument1", "someArgument2", "someArgument3", "someArgument4", ...)

Change-Id: I4bbbe2dbd1d7be9f02d63431d213088c3dee332c
Reviewed-on: https://go-review.googlesource.com/36031
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

diff --git a/src/cmd/doc/doc_test.go b/src/cmd/doc/doc_test.go
index 1244476ab2f18b05b04b6e4a54e178011696681e..454a0d6415d37ea514adc1a914877280614577f5 100644 (file)
--- a/src/cmd/doc/doc_test.go
+++ b/src/cmd/doc/doc_test.go
@@ -71,6 +71,7 @@ var tests = []test{
                        `const MultiLineConst = ...`,                                   // Multi line constant.
                        `var MultiLineVar = map\[struct{ ... }\]struct{ ... }{ ... }`,  // Multi line variable.
                        `func MultiLineFunc\(x interface{ ... }\) \(r struct{ ... }\)`, // Multi line function.
+                       `var LongLine = newLongLine\(("someArgument[1-4]", ){4}...\)`,  // Long list of arguments.
                        `type T1 = T2`, // Type alias
                },
                []string{
@@ -90,7 +91,8 @@ var tests = []test{
                        `unexportedTypedConstant`,           // No unexported typed constant.
                        `Field`,                             // No fields.
                        `Method`,                            // No methods.
-                       `type T1 T2`, // Type alias does not display as type declaration.
+                       `someArgument[5-8]`,                 // No truncated arguments.
+                       `type T1 T2`,                        // Type alias does not display as type declaration.
                },
        },
        // Package dump -u
@@ -270,7 +272,7 @@ var tests = []test{
        // Type T1 dump (alias).
        {
                "type T1",
-               []string{p+".T1"},
+               []string{p + ".T1"},
                []string{
                        `type T1 = T2`,
                },

diff --git a/src/cmd/doc/pkg.go b/src/cmd/doc/pkg.go
index 32d08f21fd04a33d4136a3f30e7355cd1fc5b8a7..b59fcbbd035f720c1bde9c4d85d60bc46166ded4 100644 (file)
--- a/src/cmd/doc/pkg.go
+++ b/src/cmd/doc/pkg.go
@@ -281,11 +281,11 @@ func (pkg *Package) oneLineNodeDepth(node ast.Node, depth int) string {
                        }
                }
 
-               param := strings.Join(params, ", ")
+               param := joinStrings(params)
                if len(results) == 0 {
                        return fmt.Sprintf("func(%s)", param)
                }
-               result := strings.Join(results, ", ")
+               result := joinStrings(results)
                if !needParens {
                        return fmt.Sprintf("func(%s) %s", param, result)
                }
@@ -338,7 +338,7 @@ func (pkg *Package) oneLineNodeDepth(node ast.Node, depth int) string {
                for _, arg := range n.Args {
                        args = append(args, pkg.oneLineNodeDepth(arg, depth))
                }
-               return fmt.Sprintf("%s(%s)", fnc, strings.Join(args, ", "))
+               return fmt.Sprintf("%s(%s)", fnc, joinStrings(args))
 
        case *ast.UnaryExpr:
                return fmt.Sprintf("%s%s", n.Op, pkg.oneLineNodeDepth(n.X, depth))
@@ -367,7 +367,21 @@ func (pkg *Package) oneLineField(field *ast.Field, depth int) string {
        if len(names) == 0 {
                return pkg.oneLineNodeDepth(field.Type, depth)
        }
-       return strings.Join(names, ", ") + " " + pkg.oneLineNodeDepth(field.Type, depth)
+       return joinStrings(names) + " " + pkg.oneLineNodeDepth(field.Type, depth)
+}
+
+// joinStrings formats the input as a comma-separated list,
+// but truncates the list at some reasonable length if necessary.
+func joinStrings(ss []string) string {
+       var n int
+       for i, s := range ss {
+               n += len(s) + len(", ")
+               if n > punchedCardWidth {
+                       ss = append(ss[:i:i], "...")
+                       break
+               }
+       }
+       return strings.Join(ss, ", ")
 }
 
 // packageDoc prints the docs for the package (package doc plus one-liners of the rest).
@@ -787,7 +801,6 @@ func (pkg *Package) printMethodDoc(symbol, method string) bool {
                        }
                        name := iMethod.Names[0].Name
                        if match(method, name) {
-                               // pkg.oneLineField(iMethod, 0)
                                if iMethod.Doc != nil {
                                        for _, comment := range iMethod.Doc.List {
                                                doc.ToText(&pkg.buf, comment.Text, "", indent, indentedWidth)

diff --git a/src/cmd/doc/testdata/pkg.go b/src/cmd/doc/testdata/pkg.go
index 0ebea67d58e50a942b2dc371f7c78b04cc78498c..4e08c84233ad3165d40fcfc8f356bb7be4c4ac9f 100644 (file)
--- a/src/cmd/doc/testdata/pkg.go
+++ b/src/cmd/doc/testdata/pkg.go
@@ -173,6 +173,19 @@ const (
 
 const ConstGroup4 ExportedType = ExportedType{}
 
+func newLongLine(ss ...string)
+
+var LongLine = newLongLine(
+       "someArgument1",
+       "someArgument2",
+       "someArgument3",
+       "someArgument4",
+       "someArgument5",
+       "someArgument6",
+       "someArgument7",
+       "someArgument8",
+)
+
 type T2 int
 
 type T1 = T2