force multiline function signatures to separate the body

closes #73

Author: Oiyoo

README.md

@@ -40,6 +40,7 @@ No empty lines at the beginning or end of a function
 
 ```
 func foo() {
+
 	println("bar")
 
 }
@@ -53,6 +54,28 @@ func foo() {
 
 </details>
 
+Functions using an empty line for readability should use a `) {` line instead
+
+<details><summary><i>example</i></summary>
+
+```
+func foo(s string,
+	i int) {
+
+	println("bar")
+}
+```
+
+```
+func foo(s string,
+	i int,
+) {
+	println("bar")
+}
+```
+
+</details>
+
 No empty lines around a lone statement (or comment) in a block
 
 <details><summary><i>example</i></summary>

format/format.go

@@ -542,12 +542,22 @@ func (f *fumpter) applyPre(c *astutil.Cursor) {
 				f.Position(sign.Results.Closing).Column == 1 &&
 				f.Line(sign.Results.Closing) == endLine
 
-			if f.Line(sign.Pos()) != endLine &&
-				// param/result closing is not the 1st char of the left bracket line
-				!(paramClosingIsFirstCharOnEndLine || resultClosingIsFirstCharOnEndLine) {
+			endLineIsIndented := !(paramClosingIsFirstCharOnEndLine || resultClosingIsFirstCharOnEndLine)
+
+			if f.Line(sign.Pos()) != endLine && endLineIsIndented {
+				// is there an empty line?
+				isThereAnEmptyLine := endLine+1 != f.Line(bodyPos)
+
 				// The body is preceded by a multi-line function
-				// signature, and the empty line helps readability.
-				return
+				// signature, we move the `) {` to avoid the empty line.
+				switch {
+				case isThereAnEmptyLine && sign.Results != nil && !resultClosingIsFirstCharOnEndLine:
+					sign.Results.Closing += 1
+					f.addNewline(sign.Results.Closing)
+				case isThereAnEmptyLine && sign.Params != nil && !paramClosingIsFirstCharOnEndLine:
+					sign.Params.Closing += 1
+					f.addNewline(sign.Params.Closing)
+				}
 			}
 		}
 

testdata/scripts/func-newlines.txt

@@ -230,6 +230,25 @@ func f2(
 
 	return "", nil
 }
+
+func multilineResultsMultipleEmptyLines() (p1 string,
+	p2 string) {
+
+
+	println("body")
+
+}
+
+func multilineParamsWithoutEmptyLine(p1 string,
+	p2 string) {
+	println("body")
+}
+
+func multilineParamsWithoutEmptyLineWithComment(p1 string,
+	p2 string) {
+	// comment
+	println("body")
+}
 -- foo.go.golden --
 package p
 
@@ -253,8 +272,8 @@ func _() {
 }
 
 func multilineParams(p1 string,
-	p2 string) {
-
+	p2 string,
+) {
 	println("body")
 }
 
@@ -380,8 +399,8 @@ func multilineParamsOneParamReturningMultiLineValues(
 }
 
 func multilineResults() (p1 string,
-	p2 string) {
-
+	p2 string,
+) {
 	println("body")
 }
 
@@ -398,8 +417,8 @@ func multilineNoFields() {
 func f(
 	foo int,
 	bar string,
-	/* baz */) {
-
+	/* baz */
+) {
 	body()
 }
 
@@ -409,7 +428,24 @@ func f2(
 ) (
 	string,
 	error,
-	/* baz */) {
-
+	/* baz */
+) {
 	return "", nil
 }
+
+func multilineResultsMultipleEmptyLines() (p1 string,
+	p2 string,
+) {
+	println("body")
+}
+
+func multilineParamsWithoutEmptyLine(p1 string,
+	p2 string) {
+	println("body")
+}
+
+func multilineParamsWithoutEmptyLineWithComment(p1 string,
+	p2 string) {
+	// comment
+	println("body")
+}