Fix trailing semicolon in parens-block

This patch make sure to keep the trailing semicolon in parens-block if
there is just a single item. Without the trailing colon the text would
be parsed as parens but not as a block (compare `(1)` vs `(1,)` for
tuples). Closes #38.

src/runestone.jl

@@ -407,7 +407,7 @@ function spaces_in_listlike(ctx::Context, node::Node)
         require_trailing_comma = false # Leads to parser error
     elseif kind(node) in KSet"block"
         require_trailing_comma = false
-        allow_trailing_semi = n_items == 0
+        allow_trailing_semi = n_items < 2
     elseif kind(node) === K"parameters"
         # For parameters the trailing comma is configured from the parent
         require_trailing_comma = has_tag(node, TAG_TRAILING_COMMA)
@@ -756,6 +756,7 @@ function spaces_in_listlike(ctx::Context, node::Node)
                 replace_bytes!(ctx, "", span(kid′))
             elseif kind(node) === K"block" && kind(kid′) === K";" && allow_trailing_semi ||
                     (kind(kid′) === K"Whitespace" && peek(i) !== K"Comment")
+                allow_trailing_semi = n_items == 0 # Only one semicolon allowed
                 accept_node!(ctx, kid′)
                 any_kid_changed && push!(kids′, kid′)
             elseif kind(kid′) === K"NewlineWs" ||

test/runtests.jl

@@ -333,12 +333,13 @@ end
             "$(x){\n    $(a), $(a); $(b),\n}"
     end
     # Trailing `;` in paren-block
-    @test format_string("(a = A;)") == "(a = A)"
-    @test format_string("cond && (a = A;)") == "cond && (a = A)"
+    @test format_string("(a = A;)") == "(a = A;)"
+    @test format_string("cond && (a = A;)") == "cond && (a = A;)"
     @test format_string("(a = A; b = B;)") == "(a = A; b = B)"
-    @test format_string("(a = A;;)") == "(a = A)"
+    @test format_string("(a = A;;)") == "(a = A;)"
     @test format_string("(;;)") == format_string("( ; ; )") == "(;;)"
     @test format_string("(;)") == format_string("( ; )") == "(;)"
+    @test format_string("(@a b(c);)") == "(@a b(c);)"
     # https://github.com/fredrikekre/Runic.jl/issues/16
     @test format_string("(i for i in\nI)") == "(\n    i for i in\n        I\n)"
     @test format_string("f(i for i in\nI)") == "f(\n    i for i in\n        I\n)"