From 37c6afa5b4c25e008206d8a036e02b7fd7189459 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <superjoe30@gmail.com>
Date: Thu, 17 May 2018 00:31:47 -0400
Subject: [PATCH] zig fmt: line comment between if block and else keyword

---
 std/zig/parse.zig       |  1 +
 std/zig/parser_test.zig | 67 +++++++++++++++++++++--------------------
 std/zig/render.zig      |  9 ++++++
 3 files changed, 45 insertions(+), 32 deletions(-)

diff --git a/std/zig/parse.zig b/std/zig/parse.zig
index 4f1e3dcefe..094d368c23 100644
--- a/std/zig/parse.zig
+++ b/std/zig/parse.zig
@@ -1017,6 +1017,7 @@ pub fn parse(allocator: &mem.Allocator, source: []const u8) !ast.Tree {
                 continue;
             },
             State.Else => |dest| {
+                while (try eatLineComment(arena, &tok_it, &tree)) |_| { }
                 if (eatToken(&tok_it, &tree, Token.Id.Keyword_else)) |else_token| {
                     const node = try arena.construct(ast.Node.Else {
                         .base = ast.Node {.id = ast.Node.Id.Else },
diff --git a/std/zig/parser_test.zig b/std/zig/parser_test.zig
index ea26f823b5..38e61fe8fe 100644
--- a/std/zig/parser_test.zig
+++ b/std/zig/parser_test.zig
@@ -1,3 +1,38 @@
+test "zig fmt: line comment between if block and else keyword" {
+    try testTransform(
+        \\test "aoeu" {
+        \\    // cexp(finite|nan +- i inf|nan) = nan + i nan
+        \\    if ((hx & 0x7fffffff) != 0x7f800000) {
+        \\        return Complex(f32).new(y - y, y - y);
+        \\    }
+        \\    // cexp(-inf +- i inf|nan) = 0 + i0
+        \\    else if (hx & 0x80000000 != 0) {
+        \\        return Complex(f32).new(0, 0);
+        \\    }
+        \\    // cexp(+inf +- i inf|nan) = inf + i nan
+        \\    // another comment
+        \\    else {
+        \\        return Complex(f32).new(x, y - y);
+        \\    }
+        \\}
+    ,
+        \\test "aoeu" {
+        \\    // cexp(finite|nan +- i inf|nan) = nan + i nan
+        \\    if ((hx & 0x7fffffff) != 0x7f800000) {
+        \\        return Complex(f32).new(y - y, y - y);
+        \\    } // cexp(-inf +- i inf|nan) = 0 + i0
+        \\    else if (hx & 0x80000000 != 0) {
+        \\        return Complex(f32).new(0, 0);
+        \\    } // cexp(+inf +- i inf|nan) = inf + i nan
+        \\    // another comment
+        \\    else {
+        \\        return Complex(f32).new(x, y - y);
+        \\    }
+        \\}
+        \\
+    );
+}
+
 test "zig fmt: same line comments in expression" {
     try testCanonical(
         \\test "aoeu" {
@@ -9,38 +44,6 @@ test "zig fmt: same line comments in expression" {
     );
 }
 
-//test "zig fmt: line comment between if block and else keyword" {
-//    try testTransform(
-//        test "aoeu" {
-//            // cexp(finite|nan +- i inf|nan) = nan + i nan
-//            if ((hx & 0x7fffffff) != 0x7f800000) {
-//                return Complex(f32).new(y - y, y - y);
-//            }
-//            // cexp(-inf +- i inf|nan) = 0 + i0
-//            else if (hx & 0x80000000 != 0) {
-//                return Complex(f32).new(0, 0);
-//            }
-//            // cexp(+inf +- i inf|nan) = inf + i nan
-//            else {
-//                return Complex(f32).new(x, y - y);
-//            }
-//        }
-//    ,
-//        test "aoeu" {
-//            // cexp(finite|nan +- i inf|nan) = nan + i nan
-//            if ((hx & 0x7fffffff) != 0x7f800000) {
-//                return Complex(f32).new(y - y, y - y);
-//            } // cexp(-inf +- i inf|nan) = 0 + i0
-//            else if (hx & 0x80000000 != 0) {
-//                return Complex(f32).new(0, 0);
-//            } // cexp(+inf +- i inf|nan) = inf + i nan
-//            else {
-//                return Complex(f32).new(x, y - y);
-//            }
-//        }
-//    );
-//}
-
 test "zig fmt: add comma on last switch prong" {
     try testTransform(
         \\test "aoeu" {
diff --git a/std/zig/render.zig b/std/zig/render.zig
index 9ce8ba0cbf..980addc77a 100644
--- a/std/zig/render.zig
+++ b/std/zig/render.zig
@@ -852,6 +852,15 @@ fn renderExpression(allocator: &mem.Allocator, stream: var, tree: &ast.Tree, ind
         },
         ast.Node.Id.Else => {
             const else_node = @fieldParentPtr(ast.Node.Else, "base", base);
+
+            var prev_tok_index = else_node.else_token - 1;
+            while (tree.tokens.at(prev_tok_index).id == Token.Id.LineComment) : (prev_tok_index -= 1) { }
+            prev_tok_index += 1;
+            while (prev_tok_index < else_node.else_token) : (prev_tok_index += 1) {
+                try stream.print("{}\n", tree.tokenSlice(prev_tok_index));
+                try stream.writeByteNTimes(' ', indent);
+            }
+
             try stream.print("{}", tree.tokenSlice(else_node.else_token));
 
             const block_body = switch (else_node.body.id) {