Fix template formatting

src/template/lib.zig

@@ -180,6 +180,13 @@ fn executeStatement(
                 context,
             );
         },
+        .format => |fmt| {
+            try std.fmt.format(
+                writer,
+                "{" ++ fmt.format ++ "}",
+                .{evaluateExpression(fmt.value, args, captures, context)},
+            );
+        },
         //else => @compileError("TODO"),
     }
 }
@@ -196,11 +203,10 @@ fn htmlEscape(writer: anytype, str: []const u8) !void {
 
 fn print(writer: anytype, arg: anytype) !void {
     const T = @TypeOf(arg);
+    if (T == void) return;
     if (comptime std.meta.trait.isZigString(T)) return htmlEscape(writer, arg);
     if (comptime std.meta.trait.isNumber(T)) return std.fmt.format(writer, "{}", .{arg});
-    @compileLog(@TypeOf(arg));
-
-    @compileError("TODO");
+    try std.fmt.format(writer, "{}", .{arg});
 }
 
 fn Deref(comptime T: type, comptime names: []const []const u8) type {
@@ -450,6 +456,9 @@ fn parseTemplate(
                         .call_template => |call| items = items ++ [_]TemplateItem{.{
                             .statement = .{ .call_template = call },
                         }},
+                        .format => |call| items = items ++ [_]TemplateItem{.{
+                            .statement = .{ .format = call },
+                        }},
                         .end_switch, .case_header => if (template_type == .switch_block)
                             break cb
                         else
@@ -514,6 +523,7 @@ fn parseTemplateTokens(comptime tokens: ControlTokenIter) []const TemplateToken
             .percent => items = items ++ [_]TemplateToken{.{ .text = "%" }},
             .open_paren => items = items ++ [_]TemplateToken{.{ .text = "(" }},
             .close_paren => items = items ++ [_]TemplateToken{.{ .text = ")" }},
+            .double_quote => items = items ++ [_]TemplateToken{.{ .text = "\"" }},
         };
 
         return items;
@@ -684,6 +694,11 @@ fn parseControlBlock(comptime tokens: ControlTokenIter) ParseResult(ControlToken
                         iter = result.new_iter;
                         break .{ .case_header = result.item };
                     },
+                    .format => {
+                        const result = parseFormat(iter);
+                        iter = result.new_iter;
+                        break .{ .format = result.item };
+                    },
 
                     //else => @compileError("TODO"),
                 }
@@ -706,7 +721,7 @@ fn parseControlBlock(comptime tokens: ControlTokenIter) ParseResult(ControlToken
                 iter = expr.new_iter;
                 break .{ .expression = expr.item };
             },
-            else => @compileError("TODO"),
+            else => @compileError("TODO " ++ @tagName(token)),
         };
 
         // search for end of statement
@@ -957,6 +972,42 @@ fn parseCallTemplate(comptime tokens: ControlTokenIter) ParseResult(ControlToken
     }
 }
 
+fn parseFormat(comptime tokens: ControlTokenIter) ParseResult(ControlTokenIter, FormatStmt) {
+    comptime {
+        var iter = skipWhitespace(tokens);
+
+        expectToken(iter.next(), .double_quote);
+        var fmt_str: []const u8 = "";
+        while (true) switch (iter.next() orelse @compileError("Unexpected end of template")) {
+            .text, .whitespace => |t| fmt_str = fmt_str ++ t,
+            .open_bracket => fmt_str = fmt_str ++ "{",
+            .close_bracket => fmt_str = fmt_str ++ "}",
+            .period => fmt_str = fmt_str ++ ".",
+            .pound => fmt_str = fmt_str ++ "#",
+            .pipe => fmt_str = fmt_str ++ "|",
+            .dollar => fmt_str = fmt_str ++ "$",
+            .slash => fmt_str = fmt_str ++ "/",
+            .equals => fmt_str = fmt_str ++ "=",
+            .at => fmt_str = fmt_str ++ "@",
+            .comma => fmt_str = fmt_str ++ ",",
+            .percent => fmt_str = fmt_str ++ "%",
+            .open_paren => fmt_str = fmt_str ++ "(",
+            .close_paren => fmt_str = fmt_str ++ ")",
+            .double_quote => break,
+        };
+
+        const expr = parseExpression(iter);
+
+        return .{
+            .new_iter = expr.new_iter,
+            .item = .{
+                .format = fmt_str,
+                .value = expr.item,
+            },
+        };
+    }
+}
+
 fn ParseResult(comptime It: type, comptime T: type) type {
     return struct {
         new_iter: It,
@@ -1032,12 +1083,18 @@ const IfHeader = struct {
     capture: ?[]const u8,
 };
 
+const FormatStmt = struct {
+    format: []const u8,
+    value: Expression,
+};
+
 const Statement = union(enum) {
     expression: Expression,
     @"for": For,
     @"if": If,
     @"switch": Switch,
     call_template: CallTemplate,
+    format: FormatStmt,
 };
 
 const ControlBlock = struct {
@@ -1053,6 +1110,7 @@ const ControlBlock = struct {
         switch_header: SwitchHeader,
         case_header: CaseHeader,
         end_switch: void,
+        format: FormatStmt,
     };
     block: Data,
     strip_before: bool,
@@ -1067,6 +1125,7 @@ const Keyword = enum {
     @"template",
     @"switch",
     @"case",
+    @"format",
 };
 
 const EndKeyword = enum {
@@ -1102,6 +1161,7 @@ const ControlToken = union(enum) {
     percent: void,
     open_paren: void,
     close_paren: void,
+    double_quote: void,
 };
 
 const ControlTokenIter = struct {
@@ -1136,6 +1196,7 @@ const ControlTokenIter = struct {
             '%' => return .{ .percent = {} },
             '(' => return .{ .open_paren = {} },
             ')' => return .{ .close_paren = {} },
+            '"' => return .{ .double_quote = {} },
             ' ', '\t', '\n', '\r' => {
                 var idx: usize = 0;
                 while (idx < remaining.len and std.mem.indexOfScalar(u8, " \t\n\r", remaining[idx]) != null) : (idx += 1) {}
@@ -1147,7 +1208,7 @@ const ControlTokenIter = struct {
             },
             else => {
                 var idx: usize = 0;
-                while (idx < remaining.len and std.mem.indexOfScalar(u8, "{}.#|$/=@,%() \t\n\r", remaining[idx]) == null) : (idx += 1) {}
+                while (idx < remaining.len and std.mem.indexOfScalar(u8, "{}.#|$/=@,%()\" \t\n\r", remaining[idx]) == null) : (idx += 1) {}
 
                 self.start += idx - 1;
                 return .{ .text = remaining[0..idx] };

src/template/test.tmp.html

@@ -26,6 +26,8 @@
         neither
       {=/if}
 
+      format: {#format "s" .x}
+
       {#switch .snap case foo =}
         foo
       {= #case bar =}

src/util/DateTime.zig

@@ -117,14 +117,16 @@ pub fn toCharArrayZ(value: DateTime) [array_len + 1:0]u8 {
     return buf;
 }
 
-pub fn format(value: DateTime, comptime _: []const u8, _: std.fmt.FormatOptions, writer: anytype) !void {
+pub fn format(value: DateTime, comptime fmt: []const u8, _: std.fmt.FormatOptions, writer: anytype) !void {
+    if (comptime std.ascii.eqlIgnoreCase(fmt, "rfc3339") or fmt.len == 0) {
         return std.fmt.format(
             writer,
             "{:0>4}-{:0>2}-{:0>2}T{:0>2}:{:0>2}:{:0>2}Z",
             .{ value.year(), value.month().numeric(), value.day(), value.hour(), value.minute(), value.second() },
         );
+    } else @compileError("Unknown DateTime format " ++ fmt);
 }
 
 pub fn jsonStringify(value: DateTime, _: std.json.StringifyOptions, writer: anytype) !void {
-    try std.fmt.format(writer, "\"{}\"", .{value});
+    try std.fmt.format(writer, "\"{rfc3339}\"", .{value});
 }