Introduce scala-indent:defition-parameter-scaling-factor v2

README.md

@@ -306,6 +306,26 @@ val xs = for (i <- 1 to 10)
          yield i
 ```
 
+### Extra indentation for method or class declarations
+
+Provided by `scala-indent:scala-indent:defition-parameter-scaling-factor`
+
+When this variable is set to `2` (or any integer, default: 1) indention for method and class
+decloration `scala-indent:step` multiply by `2` as:
+
+```scala
+case class Foo(
+    x: String,
+    y: Int
+)
+
+def foo(
+    x: String,
+    y: Int
+): Unit
+```
+
+
 ## Prettify-Symbols
 
 Scala-mode has a preconfigured list of prettify-symbols rules. The

scala-mode-indent.el

@@ -16,6 +16,14 @@ indentation will be one or two steps depending on context."
   :safe #'integerp
   :group 'scala)
 
+(defcustom scala-indent:defition-parameter-scaling-factor 1
+  "Scale the number of spaces used to indent the parameter list
+of class/function definitions. See also
+https://github.com/hvesalai/emacs-scala-mode/issues/172"
+  :type 'integer
+  :safe #'integerp
+  :group 'scala)
+
 (defcustom scala-indent:indent-value-expression nil
   "Whether or not to indent multi-line value expressions, with
 one extra step. When true, indenting will be
@@ -629,6 +637,9 @@ anchor for calculating block indent for current point (or point
              (> (line-number-at-pos) (line-number-at-pos anchor))
              (> start (match-beginning 0))))
       (+ (* 2 scala-indent:step) lead))
+     ;; optionally multiplies the step for parameter list
+     ((scala-syntax:in-definition-parameter-list-p anchor start)
+      (+ (* scala-indent:defition-parameter-scaling-factor scala-indent:step) lead))
      ;; normal block line
      (t  (+ scala-indent:step lead)))))
 

scala-mode-syntax.el

@@ -717,6 +717,17 @@ stableId"
          (forward-line -1)
          (looking-at-p scala-syntax:empty-line-re))))
 
+(defun scala-syntax:in-definition-parameter-list-p (anchor start)
+  "Return t if the (anchor, start) region is the parameter list
+of a definition(class or def)"
+  (save-excursion
+    (goto-char (or (nth 1 (syntax-ppss start)) 0))
+    (while (or (looking-at-p "\(")
+               (looking-at-p "\\["))
+      (backward-sexp))
+    (backward-sexp)
+    (looking-at-p "class\\|def")))
+
 (defun scala-syntax:skip-forward-ignorable ()
   "Moves forward over ignorable whitespace and comments. A
 completely empty line is not ignorable and will not be mobed over."