Extract helper function to Context.

Author: nojaf

src/Fantomas.Core/CodePrinter.fs

@@ -2925,7 +2925,7 @@ let genBinding (b: BindingNode) (ctx: Context) : Context =
                      +> afterLetKeyword
                      +> sepSpace
                      +> genFunctionName
-                     +> indent
+                     +> experimentalDoubleIndent
                      +> sepNln
                      +> genParameters
                      +> onlyIf nlnOnSeparateLine sepNln
@@ -2934,7 +2934,7 @@ let genBinding (b: BindingNode) (ctx: Context) : Context =
                              sepNln +> genSingleTextNode b.Equals
                          else
                              sepSpace +> genSingleTextNode b.Equals)
-                     +> unindent
+                     +> experimentalDoubleUnindent
                      +> onlyIf hasTriviaAfterLeadingKeyword unindent)
                         ctx
 

src/Fantomas.Core/Context.fs

@@ -391,6 +391,24 @@ let indent (ctx: Context) =
 let unindent (ctx: Context) =
     writerEvent (UnIndentBy ctx.Config.IndentSize) ctx
 
+let experimentalDoubleIndent (ctx: Context) =
+    let indentSize =
+        if not ctx.Config.ExperimentalDoubleIndentParameters then
+            ctx.Config.IndentSize
+        else
+            2 * ctx.Config.IndentSize
+
+    writerEvent (IndentBy indentSize) ctx
+
+let experimentalDoubleUnindent (ctx: Context) =
+    let indentSize =
+        if not ctx.Config.ExperimentalDoubleIndentParameters then
+            ctx.Config.IndentSize
+        else
+            2 * ctx.Config.IndentSize
+
+    writerEvent (UnIndentBy indentSize) ctx
+
 /// Apply function f at an absolute indent level (use with care)
 let atIndentLevel alsoSetIndent level (f: Context -> Context) (ctx: Context) =
     if level < 0 then

src/Fantomas.Core/Context.fsi

@@ -78,6 +78,15 @@ val lastWriteEventIsNewline: ctx: Context -> bool
 val indent: ctx: Context -> Context
 /// Unindent one more level based on configuration
 val unindent: ctx: Context -> Context
+
+/// Add double indent if  ExperimentalDoubleIndentParameters is active
+/// Otherwise, add single indent
+val experimentalDoubleIndent: ctx: Context -> Context
+
+/// Add double unindent if  ExperimentalDoubleIndentParameters is active
+/// Otherwise, add single unindent
+val experimentalDoubleUnindent: ctx: Context -> Context
+
 // /// Apply function f at an absolute indent level (use with care)
 val atIndentLevel: alsoSetIndent: bool -> level: int -> f: (Context -> Context) -> ctx: Context -> Context
 // /// Set minimal indentation (`atColumn`) at current column position - next newline will be indented on `max indent atColumn`