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|
const Writer = struct {
/// Calls print and then flushes the buffer.
pub fn print(self: *Writer, comptime format: []const u8, args: anytype) anyerror!void {
const State = enum {
start,
open_brace,
close_brace,
};
comptime var start_index: usize = 0;
comptime var state = State.start;
comptime var next_arg: usize = 0;
inline for (format, 0..) |c, i| {
switch (state) {
State.start => switch (c) {
'{' => {
if (start_index < i) try self.write(format[start_index..i]);
state = State.open_brace;
},
'}' => {
if (start_index < i) try self.write(format[start_index..i]);
state = State.close_brace;
},
else => {},
},
State.open_brace => switch (c) {
'{' => {
state = State.start;
start_index = i;
},
'}' => {
try self.printValue(args[next_arg]);
next_arg += 1;
state = State.start;
start_index = i + 1;
},
's' => {
continue;
},
else => @compileError("Unknown format character: " ++ [1]u8{c}),
},
State.close_brace => switch (c) {
'}' => {
state = State.start;
start_index = i;
},
else => @compileError("Single '}' encountered in format string"),
},
}
}
comptime {
if (args.len != next_arg) {
@compileError("Unused arguments");
}
if (state != State.start) {
@compileError("Incomplete format string: " ++ format);
}
}
if (start_index < format.len) {
try self.write(format[start_index..format.len]);
}
try self.flush();
}
fn write(self: *Writer, value: []const u8) !void {
_ = self;
_ = value;
}
pub fn printValue(self: *Writer, value: anytype) !void {
_ = self;
_ = value;
}
fn flush(self: *Writer) !void {
_ = self;
}
};
// syntax
|
