Support disabling automatic line breaks

Support disabling automatic line breaks With --keep_line_breaks.

README.md

@@ -55,6 +55,7 @@ found there.
 * `--split_operator_at_line_end`: *see dfmt_split_operator_at_line_end [below](#dfmt-specific-properties)*
 * `--tab_width`: *see tab_width [below](#standard-editorconfig-properties)*
 * `--template_constraint_style`: *see dfmt_template_constraint_style [below](#dfmt-specific-properties)*
+* `--keep_line_breaks`: *see dfmt_keep_line_breaks [below](#dfmt-specific-properties)*
 
 ### Example
 ```
@@ -114,6 +115,7 @@ dfmt_compact_labeled_statements | **`true`**, `false` | Place labels on the same
 dfmt_template_constraint_style | **`conditional_newline_indent`** `conditional_newline` `always_newline` `always_newline_indent` | Control the formatting of template constraints.
 dfmt_single_template_constraint_indent | `true`, **`false`** | Set if the constraints are indented by a single tab instead of two. Has only an effect if the style set to `always_newline_indent` or `conditional_newline_indent`.
 dfmt_space_before_aa_colon | `true`, **`false`** | Adds a space after an associative array key before the `:` like in older dfmt versions.
+dfmt_keep_line_breaks | `true`, **`false`** | Keep existing line breaks if these don't violate other formatting rules.
 
 ## Terminology
 * Braces - `{` and `}`

src/dfmt/config.d

@@ -57,6 +57,8 @@ struct Config
     OptionalBoolean dfmt_single_template_constraint_indent;
     ///
     OptionalBoolean dfmt_space_before_aa_colon;
+    ///
+    OptionalBoolean dfmt_keep_line_breaks;
 
     mixin StandardEditorConfigFields;
 
@@ -85,6 +87,7 @@ struct Config
         dfmt_template_constraint_style = TemplateConstraintStyle.conditional_newline_indent;
         dfmt_single_template_constraint_indent = OptionalBoolean.f;
         dfmt_space_before_aa_colon = OptionalBoolean.f;
+        dfmt_keep_line_breaks = OptionalBoolean.f;
     }
 
     /**

src/dfmt/formatter.d

@@ -567,6 +567,8 @@ private:
     }
     do
     {
+        import dfmt.editorconfig : OptionalBoolean;
+
         immutable p = current.type;
         regenLineBreakHintsIfNecessary(index);
         writeToken();
@@ -588,7 +590,23 @@ private:
             return;
         immutable bool arrayInitializerStart = p == tok!"["
             && astInformation.arrayStartLocations.canFindIndex(tokens[index - 1].index);
-        if (arrayInitializerStart && isMultilineAt(index - 1))
+
+        if (p == tok!"[" && config.dfmt_keep_line_breaks == OptionalBoolean.t)
+        {
+            IndentStack.Details detail;
+
+            detail.wrap = false;
+            detail.temp = false;
+            detail.breakEveryItem = false;
+            detail.mini = tokens[index].line == tokens[index - 1].line;
+
+            indents.push(tok!"]", detail);
+            if (!detail.mini)
+            {
+                newline();
+            }
+        }
+        else if (arrayInitializerStart && isMultilineAt(index - 1))
         {
             // Use the close bracket as the indent token to distinguish
             // the array initialiazer from an array index in the newline
@@ -643,6 +661,10 @@ private:
         {
             newline();
         }
+        else if (onNextLine)
+        {
+            newline();
+        }
     }
 
     void formatRightParen()
@@ -659,6 +681,10 @@ private:
         if (indents.topIs(tok!"("))
             indents.pop();
 
+        if (onNextLine)
+        {
+            newline();
+        }
         if (parenDepth == 0 && (peekIs(tok!"is") || peekIs(tok!"in")
             || peekIs(tok!"out") || peekIs(tok!"do") || peekIsBody))
         {
@@ -711,6 +737,7 @@ private:
             writeParens(false);
             if (tokens[index].type == tok!"{")
                 return;
+
             if (index < tokens.length && tokens[index - 1].line < tokens[index].line
                     && astInformation.atAttributeStartLocations.canFindIndex(atIndex))
                 newline();
@@ -722,8 +749,17 @@ private:
                 || currentIs(tok!"extern")
                 || currentIs(tok!"identifier"))
                 && !currentIsIndentedTemplateConstraint())
+        {
+            if (onNextLine)
+            {
+                newline();
+            }
+            else
+            {
                 write(" ");
             }
+        }
+    }
 
     void formatColon()
     {
@@ -1228,19 +1264,39 @@ private:
             break;
         default:
             if (peekBackIs(tok!"identifier"))
+            {
+                if (onNextLine)
+                {
+                    newline();
+                }
+                else
+                {
                     write(" ");
+                }
+            }
             if (index + 1 < tokens.length)
             {
                 if (!peekIs(tok!"@") && (peekIsOperator()
                         || peekIs(tok!"out") || peekIs(tok!"in")))
+                {
                     writeToken();
+                }
                 else
                 {
                     writeToken();
                     if (!currentIsIndentedTemplateConstraint())
+                    {
+                        if (onNextLine)
+                        {
+                            newline();
+                        }
+                        else
+                        {
                             write(" ");
                         }
                     }
+                }
+            }
             else
                 writeToken();
             break;
@@ -1258,6 +1314,7 @@ private:
 
     void formatOperator()
     {
+        import dfmt.editorconfig : OptionalBoolean;
         import std.algorithm : canFind;
 
         switch (current.type)
@@ -1341,8 +1398,8 @@ private:
         case tok!".":
             regenLineBreakHintsIfNecessary(index);
             immutable bool ufcsWrap = astInformation.ufcsHintLocations.canFindIndex(current.index);
-            if (ufcsWrap || linebreakHints.canFind(index) || (linebreakHints.length == 0
+            if (ufcsWrap || linebreakHints.canFind(index) || onNextLine
-                    && currentLineLength + nextTokenLength() > config.max_line_length))
+                    || (linebreakHints.length == 0 && currentLineLength + nextTokenLength() > config.max_line_length))
             {
                 pushWrapIndent();
                 newline();
@@ -1398,7 +1455,38 @@ private:
         case tok!"%":
         binary:
             immutable bool isWrapToken = linebreakHints.canFind(index);
-            if (config.dfmt_split_operator_at_line_end)
+            if (config.dfmt_keep_line_breaks == OptionalBoolean.t && index > 0)
+            {
+                const operatorLine = tokens[index].line;
+                const rightOperandLine = tokens[index + 1].line;
+
+                if (tokens[index - 1].line < operatorLine)
+                {
+                    if (!indents.topIs(tok!"enum"))
+                        pushWrapIndent();
+                    newline();
+                }
+                else
+                {
+                    write(" ");
+                }
+                if (rightOperandLine > operatorLine
+                        && !indents.topIs(tok!"enum"))
+                {
+                    pushWrapIndent();
+                }
+                writeToken();
+
+                if (rightOperandLine > operatorLine)
+                {
+                    newline();
+                }
+                else
+                {
+                    write(" ");
+                }
+            }
+            else if (config.dfmt_split_operator_at_line_end)
             {
                 if (isWrapToken)
                 {
@@ -1442,8 +1530,10 @@ private:
 
     void formatComma()
     {
+        import dfmt.editorconfig : OptionalBoolean;
         import std.algorithm : canFind;
 
+        if (config.dfmt_keep_line_breaks == OptionalBoolean.f)
             regenLineBreakHintsIfNecessary(index);
         if (indents.indentToMostRecent(tok!"enum") != -1
                 && !peekIs(tok!"}") && indents.topIs(tok!"{") && parenDepth == 0)
@@ -1474,6 +1564,24 @@ private:
             writeToken();
             newline();
         }
+        else if (config.dfmt_keep_line_breaks == OptionalBoolean.t)
+        {
+            const commaLine = tokens[index].line;
+
+            writeToken();
+            if (!currentIs(tok!")") && !currentIs(tok!"]")
+                    && !currentIs(tok!"}") && !currentIs(tok!"comment"))
+            {
+                if (tokens[index].line == commaLine)
+                {
+                    write(" ");
+                }
+                else
+                {
+                    newline();
+                }
+            }
+        }
         else
         {
             writeToken();
@@ -2023,6 +2131,15 @@ const pure @safe @nogc:
         return index < tokens.length && tokens[index].type == tokenType;
     }
 
+    bool onNextLine() @nogc nothrow pure @safe
+    {
+        import dfmt.editorconfig : OptionalBoolean;
+
+        return config.dfmt_keep_line_breaks == OptionalBoolean.t
+            && index > 0
+            && tokens[index - 1].line < tokens[index].line;
+    }
+
     /// Bugs: not unicode correct
     size_t tokenEndLine(const Token t)
     {

src/dfmt/main.d

@@ -92,6 +92,9 @@ else
             case "space_before_aa_colon":
                 optConfig.dfmt_space_before_aa_colon = optVal;
                 break;
+            case "keep_line_breaks":
+                optConfig.dfmt_keep_line_breaks = optVal;
+                break;
             default:
                 assert(false, "Invalid command-line switch");
             }
@@ -121,7 +124,8 @@ else
                 "single_template_constraint_indent", &handleBooleans,
                 "space_before_aa_colon", &handleBooleans,
                 "tab_width", &optConfig.tab_width,
-                "template_constraint_style", &optConfig.dfmt_template_constraint_style);
+                "template_constraint_style", &optConfig.dfmt_template_constraint_style,
+                "keep_line_breaks", &handleBooleans);
             // dfmt on
         }
         catch (GetOptException e)
@@ -308,6 +312,7 @@ Formatting Options:
     --indent_size
     --indent_style, -t          `,
             optionsToString!(typeof(Config.indent_style)), `
+    --keep_line_breaks
     --soft_max_line_length
     --max_line_length
     --outdent_attributes

tests/allman/keep_line_breaks.d.ref

@@ -0,0 +1,29 @@
+@safe nothrow
+@Read
+@NonNull
+public
+int[] func(int argument_1_1, int argument_1_2,
+        int argument_2_1, int argument_2_2,
+        int argument_3_1, int argument_3_2)
+{
+    if (true && true
+            && true && true
+            && true && true)
+    {
+    }
+    else if (true && true &&
+            true && true &&
+            true && true)
+    {
+    }
+
+    func(argument_1_1).func(argument_1_2)
+        .func(argument_2_1)
+        .func(argument_2_2);
+
+    return [
+        3, 5,
+        5, 7,
+        11, 13,
+    ];
+}

tests/keep_line_breaks.args

@@ -0,0 +1 @@
+--keep_line_breaks true

tests/keep_line_breaks.d

@@ -0,0 +1,29 @@
+@safe nothrow
+@Read
+@NonNull
+public
+int[] func(int argument_1_1, int argument_1_2,
+        int argument_2_1, int argument_2_2,
+        int argument_3_1, int argument_3_2)
+{
+    if (true && true
+            && true && true
+            && true && true)
+    {
+    }
+    else if (true && true &&
+            true && true &&
+            true && true)
+    {
+    }
+
+    func(argument_1_1).func(argument_1_2)
+        .func(argument_2_1)
+        .func(argument_2_2);
+
+    return [
+        3, 5,
+        5, 7,
+        11, 13,
+    ];
+}

tests/otbs/keep_line_breaks.d.ref

@@ -0,0 +1,25 @@
+@safe nothrow
+@Read
+@NonNull
+public
+int[] func(int argument_1_1, int argument_1_2,
+        int argument_2_1, int argument_2_2,
+        int argument_3_1, int argument_3_2) {
+    if (true && true
+            && true && true
+            && true && true) {
+    } else if (true && true &&
+            true && true &&
+            true && true) {
+    }
+
+    func(argument_1_1).func(argument_1_2)
+        .func(argument_2_1)
+        .func(argument_2_2);
+
+    return [
+        3, 5,
+        5, 7,
+        11, 13,
+    ];
+}