Fix whitespace before comment in operator formatting (#89)

src/runestone.jl

@@ -149,6 +149,8 @@ function spaces_around_x(ctx::Context, node::Node, is_x::F, n_leaves_per_x::Int
     looking_for_x = false
     n_x_leaves_visited = 0
 
+    peek(kids, i) = i < length(kids) ? kind(kids[i + 1]) : nothing
+
     for (i, kid) in pairs(kids)
         if kind(kid) === K"NewlineWs" ||
                 (i == 1 && kind(kid) === K"Whitespace")
@@ -160,7 +162,8 @@ function spaces_around_x(ctx::Context, node::Node, is_x::F, n_leaves_per_x::Int
             any_changes && push!(kids′, kid)
             looking_for_whitespace = false
         elseif looking_for_whitespace
-            if kind(kid) === K"Whitespace" && span(kid) == 1
+            if (kind(kid) === K"Whitespace" && span(kid) == 1) ||
+                    (kind(kid) === K"Whitespace" && peek(kids, i) === K"Comment" && peek(kids, i + 1) === K"NewlineWs")
                 # All good, just advance the IO
                 accept_node!(ctx, kid)
                 any_changes && push!(kids′, kid)

test/runtests.jl

@@ -182,8 +182,9 @@ end
             @test format_string("$(sp)a$(sp)$(op)$(sp)\nb$(sp)") ==
                 "$(sp)a $(op)\n    b$(sp)"
             # a op # comment \n b
+            minspace = sp == "" ? " " : sp
             @test format_string("$(sp)a$(sp)$(op)$(sp)# comment\nb$(sp)") ==
-                "$(sp)a $(op) # comment\n    b$(sp)"
+                "$(sp)a $(op)$(minspace)# comment\n    b$(sp)"
         end
         # Exceptions to the rule: `:`, `..`, and `^`
         # a:b