silk lily
For can I get
pub fn stringify(self: Value) []u8 {
var l = std.ArrayList(u8);
defer l.deinit();
std.fmt.allocPrint(
l,
switch (self.get_type) {
.NAN => "NaN",
.INTEGER, .FLOAT => "{d}",
.BOOLEAN => "",
},
.{self.value},
);
return l.Slice();
}
to compile?
exotic relic
first off, allocPrint requires an allocator, since it's, allocating.
i recommend you pass in an allocator with stringify function
silk lily
right yeah
exotic relic
pub fn stringify(self: Value, alloc: std.mem.Allocator)
you know, there is a much better way to do this in general
exotic relic
because of how std.fmt.format works, if you place a function called format into Value, itll call it instead
so you can place a function into Value like this:
pub fn format(
value: Value,
comptime fmt: []const u8,
options: std.fmt.FormatOptions,
writer: anytype,
) !void {}
and just print to the writer with try writer.print("something", .{foo});
silk lily
hang on. like this?
pub fn format(
self: Value,
comptime fmt: []const u8,
options: std.fmt.FormatOptions,
writer: anytype,
) !void {
_ = fmt;
_ = options;
const str = switch (self.get_type) {
.NAN => "NaN",
.INTEGER, .FLOAT => "{d}",
.NONE => "none",
.PTR => "ptr to {x}",
.BOOLEAN => if (self.decode_bool()) {
"true";
} else {
"false";
},
};
try writer.print(str, .{self.value});
}
also yeah if statements might not work that way
exotic relic
that's almost right
just dont use brackets with the if statement
if (self.decode_bool()) "true" else "false",
ah I remember now
I did that a while ago, I just forgot
will it compile if writer is an Anytype?
exotic relic
yes
silk lily
oh, will that be resolved at compile time or something
exotic relic
yes
exotic relic
what is your end goal here?
void parrot
To answer the original question:
fn to_string(x: X, ally: Allocator) ![]const u8 {
var out = std.ArrayList(u8).init(ally);
errdefer out.deinit();
...
return try out.toOwnedSlice();
}
But indeed, you don't necessarily want to have this kind of function, because you almost always want to format this string as part of another string - and so, using some sort of writer is better.
fn to_writer(x: X, w: anytype) !void {
...
}
And indeed, if you are only doing this for the purposes of debugging or otherwise just printing it out, then you can consider overriding how {} formats a value for stuff like std.debug.print -- which is what that fn format function does.
exotic relic
if your end goal is to create a string with this format, you can now use allocPrint
you will use it like this:
pub fn stringify(self: Value, alloc: std.mem.Allocator) ![]const u8 {
return std.fmt.allocPrint(
alloc,
"{}",
.{self.value},
);
}
and std.fmt.format will auto call that format function you just made
silk lily
my end goal is to write a test to verify the output of the value
const alloc = testing.allocator;
test "test float" {
const val = Value.encode_float(-512.1234).stringify(alloc);
try testing.expectEqual("-512.1234", val);
}
oh my god how do I compare strings
exotic relic
std.mem.eql
silk lily
How can I use that with expectequal? Since I would like it to print if it's wrong
try testing.expectEqual("-512.1234", val);```or print what the wrong output is
steep plaza
expectEqualStrings
silk lily
oh lol
steep plaza
hang on. like this?
```
pub fn format(
self: Value,
comptime fm...
pretty sure this wont work since you need a comptime known format string
silk lily
it seems to work