Handle properly stringifying multiline named tuple literals

spec/compiler/parser/to_s_spec.cr

@@ -490,4 +490,125 @@ describe "ASTNode#to_s" do
       end
     end
     CRYSTAL
+
+  expect_to_s %({% {id: 10} %})
+  expect_to_s <<-'CR'
+    {%
+      data = {__nil: nil}
+      data["foo"] = {
+        id: 1,
+        active: true,
+        name: "foo".upcase,
+        pie: 3.14,
+      }
+    %}
+    CR
+
+  expect_to_s <<-'CR'
+    {%
+      data = {__nil: nil}
+      data["foo"] = {
+        id: 1, active: true,
+        name: "foo".upcase,
+        pie: 3.14,
+      }
+    %}
+    CR
+
+  expect_to_s <<-'CR'
+    {%
+      data = {__nil: nil}
+      data["foo"] = {
+        id: 1, active: true,
+        name: "foo".upcase,
+        pie: 3.14, biz: "baz", blah: false,
+      }
+    %}
+    CR
+
+  expect_to_s <<-'CR'
+    {%
+      {
+        id: 1,
+
+        blah: false,
+
+        pie: 3.14,
+      }
+    %}
+    CR
+
+  expect_to_s <<-'CR', <<-'CR'
+    {%
+      {
+        id: 1,
+
+        # Foo
+        pie: 3.14,
+      }
+    %}
+    CR
+    {%
+      {
+        id: 1,
+
+
+        pie: 3.14,
+      }
+    %}
+    CR
+
+  expect_to_s <<-'CR', <<-'CR'
+    macro finished
+      {% verbatim do %}
+        {%
+          nt = {
+            id: 1,
+
+            # Foo
+            pie: 3.14,
+          }
+        %}
+      {% end %}
+    end
+    CR
+    macro finished
+      {% verbatim do %}
+        {%
+          nt = {
+            id: 1,
+
+
+            pie: 3.14,
+          }
+        %}
+      {% end %}
+    end
+    CR
+
+  expect_to_s <<-'CR'
+    {%
+      {
+        id: 1,
+        blah: false,
+        pie: 3.14}
+    %}
+    CR
+
+  expect_to_s <<-'CR'
+    {%
+      {id: 1,
+        blah: false,
+        pie: 3.14}
+    %}
+    CR
+
+  expect_to_s <<-'CR'
+    {%
+      {id: 1,
+        blah: false,
+        pie: 3.14,
+      }
+    %}
+    CR
 end

src/compiler/crystal/syntax/to_s.cr

@@ -202,11 +202,61 @@ module Crystal
 
     def visit(node : NamedTupleLiteral)
       @str << '{'
-      node.entries.join(@str, ", ") do |entry|
+
+      # short-circuit to handle empty named tuple context
+      if node.entries.empty?
+        @str << '}'
+        return false
+      end
+
+      # A node starts multiline when its starting brace is on a different line than the staring line of it's first entry
+      start_multiline = (start_loc = node.location) && (first_entry_loc = node.entries.first?.try &.value.location) && first_entry_loc.line_number > start_loc.line_number
+
+      # and similarly ends multiline if its last entry's end location is on a different line than its ending brace
+      end_multiline = (last_entry_loc = node.entries.last?.try &.value.end_location) && (end_loc = node.end_location) && end_loc.line_number > last_entry_loc.line_number
+
+      last_entry = node.entries.first
+
+      if start_multiline
+        newline
+        @indent += 1
+        append_indent
+      end
+
+      node.entries.each_with_index do |entry, idx|
+        write_extra_newlines (last_entry.value || entry.value).end_location, entry.value.location
+
+        if (current_entry_loc = entry.value.location) && (last_entry_loc = last_entry.value.location) && current_entry_loc.line_number > last_entry_loc.line_number
+          newline
+
+          # If the node is not starting multiline, explicitly enable it once there is a line break to ensure additional values are indented properly
+          unless start_multiline
+            start_multiline = true
+            @indent += 1
+          end
+
+          append_indent
+        elsif !idx.zero?
+          @str << ' '
+        end
+
         visit_named_arg_name(entry.key)
         @str << ": "
         entry.value.accept self
+
+        last_entry = entry
+
+        @str << ',' unless idx == node.entries.size - 1
       end
+
+      @indent -= 1 if start_multiline
+
+      if end_multiline
+        @str << ','
+        newline
+        append_indent
+      end
+
       @str << '}'
       false
     end