feat: add --compact-function-args flag to control function argument formatting

.gitignore

@@ -15,5 +15,6 @@
 vendor
 .vscode
 golines
+.idea
 
 coverage.out

main.go

@@ -30,6 +30,9 @@ var (
 		"chain-split-dots",
 		"Split chained methods on the dots as opposed to the arguments").
 		Default("true").Bool()
+	compactFunctionArgs = kingpin.Flag(
+		"compact-function-args",
+		"Compact function arguments to single line in signatures and calls").Bool()
 	debug = kingpin.Flag(
 		"debug",
 		"Show debug output").Short('d').Default("false").Bool()
@@ -117,15 +120,16 @@ func main() {
 
 func run() error {
 	config := ShortenerConfig{
-		MaxLen:           *maxLen,
-		TabLen:           *tabLen,
-		KeepAnnotations:  *keepAnnotations,
-		ShortenComments:  *shortenComments,
-		ReformatTags:     *reformatTags,
-		IgnoreGenerated:  *ignoreGenerated,
-		DotFile:          *dotFile,
-		BaseFormatterCmd: *baseFormatterCmd,
-		ChainSplitDots:   *chainSplitDots,
+		MaxLen:              *maxLen,
+		TabLen:              *tabLen,
+		KeepAnnotations:     *keepAnnotations,
+		ShortenComments:     *shortenComments,
+		ReformatTags:        *reformatTags,
+		IgnoreGenerated:     *ignoreGenerated,
+		DotFile:             *dotFile,
+		BaseFormatterCmd:    *baseFormatterCmd,
+		ChainSplitDots:      *chainSplitDots,
+		CompactFunctionArgs: *compactFunctionArgs,
 	}
 	shortener := NewShortener(config)
 

shortener.go

@@ -35,14 +35,15 @@ const maxRounds = 20
 
 // ShortenerConfig stores the configuration options exposed by a Shortener instance.
 type ShortenerConfig struct {
-	MaxLen          int    // Max target width for each line
-	TabLen          int    // Width of a tab character
-	KeepAnnotations bool   // Whether to keep annotations in final result (for debugging only)
-	ShortenComments bool   // Whether to shorten comments
-	ReformatTags    bool   // Whether to reformat struct tags in addition to shortening long lines
-	IgnoreGenerated bool   // Whether to ignore generated files
-	DotFile         string // Path to write dot-formatted output to (for debugging only)
-	ChainSplitDots  bool   // Whether to split chain methods by putting dots at ends of lines
+	MaxLen              int    // Max target width for each line
+	TabLen              int    // Width of a tab character
+	KeepAnnotations     bool   // Whether to keep annotations in final result (for debugging only)
+	ShortenComments     bool   // Whether to shorten comments
+	ReformatTags        bool   // Whether to reformat struct tags in addition to shortening long lines
+	IgnoreGenerated     bool   // Whether to ignore generated files
+	DotFile             string // Path to write dot-formatted output to (for debugging only)
+	ChainSplitDots      bool   // Whether to split chain methods by putting dots at ends of lines
+	CompactFunctionArgs bool   // Whether to compact function arguments to single line in signatures and calls
 
 	// Formatter that will be run before and after main shortening process. If empty,
 	// defaults to goimports (if found), otherwise gofmt.
@@ -401,14 +402,28 @@ func (s *Shortener) formatDecl(decl dst.Decl) {
 
 // formatFieldList formats a field list in a function declaration.
 func (s *Shortener) formatFieldList(fieldList *dst.FieldList) {
-	for f, field := range fieldList.List {
-		if f == 0 {
-			field.Decorations().Before = dst.NewLine
-		} else {
+	if s.config.CompactFunctionArgs {
+		for i, field := range fieldList.List {
 			field.Decorations().Before = dst.None
+			field.Decorations().After = dst.None
+
+			if i == 0 {
+				field.Decorations().Before = dst.NewLine
+			}
+			if i == len(fieldList.List)-1 {
+				field.Decorations().After = dst.NewLine
+			}
 		}
+	} else {
+		for f, field := range fieldList.List {
+			if f == 0 {
+				field.Decorations().Before = dst.NewLine
+			} else {
+				field.Decorations().Before = dst.None
+			}
 
-		field.Decorations().After = dst.NewLine
+			field.Decorations().After = dst.NewLine
+		}
 	}
 }
 
@@ -514,17 +529,35 @@ func (s *Shortener) formatExpr(expr dst.Expr, force bool, isChain bool) {
 		} else {
 			shortenChildArgs := shouldShorten || HasAnnotationRecursive(e)
 
-			for a, arg := range e.Args {
-				if shortenChildArgs {
-					if a == 0 {
-						arg.Decorations().Before = dst.NewLine
-					} else {
+			if s.config.CompactFunctionArgs {
+				for i, arg := range e.Args {
+					if shortenChildArgs {
+						arg.Decorations().Before = dst.None
 						arg.Decorations().After = dst.None
+
+						if i == 0 {
+							arg.Decorations().Before = dst.NewLine
+						}
+						if i == len(e.Args)-1 {
+							arg.Decorations().After = dst.NewLine
+						}
+					}
+					s.formatExpr(arg, false, isChain)
+				}
+			} else {
+				for a, arg := range e.Args {
+					if shortenChildArgs {
+						if a == 0 {
+							arg.Decorations().Before = dst.NewLine
+						} else {
+							arg.Decorations().After = dst.None
+						}
+						arg.Decorations().After = dst.NewLine
 					}
-					arg.Decorations().After = dst.NewLine
+					s.formatExpr(arg, false, isChain)
 				}
-				s.formatExpr(arg, false, isChain)
 			}
+
 			s.formatExpr(e.Fun, shouldShorten, isChain)
 		}
 	case *dst.CompositeLit: