From 79641c7ac6291ab709470ff0fdb22364b534b807 Mon Sep 17 00:00:00 2001
From: George Dietrich <dev@dietrich.pub>
Date: Mon, 23 Dec 2024 10:37:19 -0500
Subject: [PATCH] Handle emitting significant whitespace as well

---
 spec/compiler/parser/to_s_spec.cr   | 15 +++++++++------
 src/compiler/crystal/syntax/to_s.cr | 27 ++++++++++++++++++++++++---
 2 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/spec/compiler/parser/to_s_spec.cr b/spec/compiler/parser/to_s_spec.cr
index ed28ecd55dd1..3ea28be4e46e 100644
--- a/spec/compiler/parser/to_s_spec.cr
+++ b/spec/compiler/parser/to_s_spec.cr
@@ -1,7 +1,7 @@
 require "../../support/syntax"
 
-private def expect_to_s(original, expected = original, emit_doc = false, file = __FILE__, line = __LINE__)
-  it "does to_s of #{original.inspect}", file, line do
+private def expect_to_s(original, expected = original, emit_doc = false, file = __FILE__, line = __LINE__, focus = false)
+  it "does to_s of #{original.inspect}", file, line, focus: focus do
     str = IO::Memory.new expected.bytesize
 
     source = original
@@ -262,8 +262,7 @@ describe "ASTNode#to_s" do
   expect_to_s "{%\n  a = 1 %}", "{%\n  a = 1\n%}"
   expect_to_s "{% a = 1\n%}", "{% a = 1 %}"
 
-  # FIXME: Should respect significant whitespace
-  expect_to_s <<-'CR', <<-'CR'
+  expect_to_s <<-'CR', <<-CR
     macro finished
       {% verbatim do %}
         {%
@@ -280,14 +279,16 @@ describe "ASTNode#to_s" do
       {% verbatim do %}
         {%
           10
+
+
+
           20
         %}
       {% end %}
     end
     CR
 
-  # FIXME: Should respect significant whitespace
-  expect_to_s <<-'CR', <<-'CR'
+  expect_to_s <<-'CR', <<-CR
     macro finished
       {% verbatim do %}
         {%
@@ -303,6 +304,8 @@ describe "ASTNode#to_s" do
       {% verbatim do %}
         {%
           10
+
+
           20
         %}
       {% end %}
diff --git a/src/compiler/crystal/syntax/to_s.cr b/src/compiler/crystal/syntax/to_s.cr
index d30e2dd52d7f..5d8d28820c68 100644
--- a/src/compiler/crystal/syntax/to_s.cr
+++ b/src/compiler/crystal/syntax/to_s.cr
@@ -55,6 +55,21 @@ module Crystal
       true
     end
 
+    private def add_whitespace_around(first_node_location : Location?, second_node_location : Location?, &) : Nil
+      # If any location information is missing, don't add any extra newlines.
+      if !first_node_location || !second_node_location
+        yield
+        return
+      end
+
+      # Only emit extra newlines. I.e. those more than the first handled via the Expressions visitor.
+      ((second_node_location.line_number - 1) - first_node_location.line_number).times do
+        newline
+      end
+
+      yield
+    end
+
     def visit(node : Nop)
       false
     end
@@ -221,11 +236,17 @@ module Crystal
       if @inside_macro > 0
         node.expressions.each &.accept self
       else
+        last_node = node.expressions.first
+
         node.expressions.each_with_index do |exp, i|
           unless exp.nop?
-            append_indent unless node.keyword.paren? && i == 0
-            exp.accept self
-            newline unless node.keyword.paren? && i == node.expressions.size - 1
+            self.add_whitespace_around last_node.end_location, exp.location do
+              append_indent unless node.keyword.paren? && i == 0
+              exp.accept self
+              newline unless node.keyword.paren? && i == node.expressions.size - 1
+            end
+
+            last_node = exp
           end
         end
       end