Support single-quoted attribute values

[umajho]

It would be nice to support using single quotes instead of double quotes to surround attribute values.

For example, if I put a JSON string in an attribute, the render result can be filled with "s:

<!-- total: 1826 bytes; `&quot;`s: 888 bytes (~48.63% of total). -->
<x-foo-table class="x h-full" foos="[{&quot;id&quot;:379338656,&quot;name&quot;:&quot;******&quot;,&quot;type&quot;:&quot;general&quot;,&quot;createdAt&quot;:&quot;2025-08-08T20:17:39.663373Z&quot;,&quot;note&quot;:&quot;test&quot;},{&quot;id&quot;:141015513,&quot;name&quot;:&quot;******&quot;,&quot;type&quot;:&quot;general&quot;,&quot;createdAt&quot;:&quot;2025-08-08T21:59:38.912249Z&quot;},{&quot;id&quot;:158390610,&quot;name&quot;:&quot;******&quot;,&quot;type&quot;:&quot;creation_dedicated&quot;,&quot;createdAt&quot;:&quot;2025-08-08T22:01:50.388961Z&quot;},{&quot;id&quot;:394389570,&quot;name&quot;:&quot;******&quot;,&quot;type&quot;:&quot;creation_dedicated&quot;,&quot;createdAt&quot;:&quot;2025-08-08T22:01:55.365973Z&quot;},{&quot;id&quot;:974399273,&quot;name&quot;:&quot;******&quot;,&quot;type&quot;:&quot;creation_dedicated&quot;,&quot;createdAt&quot;:&quot;2025-08-08T22:05:20.970877Z&quot;},{&quot;id&quot;:17757763,&quot;name&quot;:&quot;******&quot;,&quot;type&quot;:&quot;creation_dedicated&quot;,&quot;createdAt&quot;:&quot;2025-08-08T22:05:22.365469Z&quot;},{&quot;id&quot;:1729396425,&quot;name&quot;:&quot;******&quot;,&quot;type&quot;:&quot;creation_dedicated&quot;,&quot;createdAt&quot;:&quot;2025-08-08T22:05:23.820177Z&quot;},{&quot;id&quot;:1392435214,&quot;name&quot;:&quot;******&quot;,&quot;type&quot;:&quot;creation_dedicated&quot;,&quot;createdAt&quot;:&quot;2025-08-08T22:05:25.439Z&quot;},{&quot;id&quot;:1338106766,&quot;name&quot;:&quot;******&quot;,&quot;type&quot;:&quot;creation_dedicated&quot;,&quot;createdAt&quot;:&quot;2025-08-08T22:01:56.884257Z&quot;,&quot;note&quot;:&quot;x&quot;},{&quot;id&quot;:1689333865,&quot;name&quot;:&quot;******&quot;,&quot;type&quot;:&quot;creation_dedicated&quot;,&quot;createdAt&quot;:&quot;2025-08-09T07:52:19.403957Z&quot;}]"></x-foo-table>

If I switch to using single quotes, the result is much clearer:

<!-- total: 1086 bytes. -->
<x-foo-table class='x h-full' foos='[{"id":379338656,"name":"******","type":"general","createdAt":"2025-08-08T20:17:39.663373Z","note":"test"},{"id":141015513,"name":"******","type":"general","createdAt":"2025-08-08T21:59:38.912249Z"},{"id":158390610,"name":"******","type":"creation_dedicated","createdAt":"2025-08-08T22:01:50.388961Z"},{"id":394389570,"name":"******","type":"creation_dedicated","createdAt":"2025-08-08T22:01:55.365973Z"},{"id":974399273,"name":"******","type":"creation_dedicated","createdAt":"2025-08-08T22:05:20.970877Z"},{"id":17757763,"name":"******","type":"creation_dedicated","createdAt":"2025-08-08T22:05:22.365469Z"},{"id":1729396425,"name":"******","type":"creation_dedicated","createdAt":"2025-08-08T22:05:23.820177Z"},{"id":1392435214,"name":"******","type":"creation_dedicated","createdAt":"2025-08-08T22:05:25.439Z"},{"id":1338106766,"name":"******","type":"creation_dedicated","createdAt":"2025-08-08T22:01:56.884257Z","note":"x"},{"id":1689333865,"name":"******","type":"creation_dedicated","createdAt":"2025-08-09T07:52:19.403957Z"}]'></x-foo-table>

Maybe this behavior can be enabled with a new feature flag like single-quoted-attributes.

[vidhanio]

unfortunately rust cannot parse '...' as anything other than a char, meaning multiple characters inside the quotes are a syntax error. i have an alternative solution that i'm thinking of, being a special syntax for specifying an attribute will be single-quoted and splitting the AttributeValue context into AttributeValue<DoubleQuoted> and AttributeValue<SingleQuoted>. i will def give this a longer think when i've fleshed it out more.

[umajho]

Do you think we could implement this by introducing new wrapper types resembling Raw?
This way, we wouldn't need to change the syntax.

Example:

use hypertext::{SingleQuoted, DoubleQuoted, prelude::*};
use serde_json::json;

let rendered_maud = maud! {
    // always uses single quotes:
    div data-json=(SingleQuoted::new(json!({ "hello": "world" }).to_string())) {}
    // alternatively:
    div data-json=(SingleQuoted(json!({ "hello": "world" }).to_string())) {}

    // always uses double quotes:
    div data-json=(DoubleQuoted::new(json!({ "hello": "world" }).to_string())) {}

    // uses the default configuration (maybe determined by a feature flag?):
    div data-json=(json!({ "hello": "world" }).to_string()) {}
}
.render();

On an unrelated note:

I noticed that with the maud crate, I can write div data-json=((json! ({ "hello": "world" })) {} without the .to_string() part, but hypertext doesn't seem to support this.

Do you think I should create a new issue for this?

[vidhanio]

@umajho

for the first part: no, because the macro itself adds the "" (or in this case '') around the attribute. the macro would have to be aware of the attribute quoting type.

for the second part, this is due to lambda-fairy/maud#359, where it falls back to Display to render. imo this was a little hacky and could lead to unexpected hidden behaviour which isn't clearly visible by looking at the code. instead in this crate, using div data-json=%(json! ({ "hello": "world" }) {} (with a % before the ()) will render the inner expression via Display. note that ?(...) will do the same for Debug. these allow you to avoid an extra allocation from the to_string, as they directly write the escaped Displayed stuff to the buffer. :)

[umajho]

@umajho

for the first part: no, because the macro itself adds the "" (or in this case '') around the attribute. the macro would have to be aware of the attribute quoting type.

for the second part, this is due to lambda-fairy/maud#359, where it falls back to Display to render. imo this was a little hacky and could lead to unexpected hidden behaviour which isn't clearly visible by looking at the code. instead in this crate, using div data-json=%(json! ({ "hello": "world" }) {} (with a % before the ()) will render the inner expression via Display. note that ?(...) will do the same for Debug. these allow you to avoid an extra allocation from the to_string, as they directly write the escaped Displayed stuff to the buffer. :)

Ohh, I see. Thank you for your patient explanation!

[vidhanio]

no worries! i am still trying to come up with a clean way to do this, i'll definitely let yk if there are any updates. :)

[vidhanio]

@umajho i've come up with a potential way to do this. how does this api look?

crate hypertext_macros {
	// ...

	#[proc_macro]
	pub fn maud_single_quoted(tokens: TokenStream) -> TokenStream { ... }


	#[proc_macro]
	pub fn rsx_single_quoted(tokens: TokenStream) -> TokenStream { ... }


	#[proc_macro]
	pub fn attribute_single_quoted(tokens: TokenStream) -> TokenStream { ... }

	// etc.
}

crate hypertext {
	// ...

	pub mod single_quoted {
		pub use hypertext_macros::maud_single_quoted as maud;
		pub use hypertext_macros::rsx_single_quoted as rsx;
		pub use hypertext_macros::attribute_single_quoted as attribute;
		// etc.
	}

	pub mod prelude {
		// ...
		pub use crate::single_quoted;
	}
}

use hypertext::prelude::*;

assert_eq!(
	single_quoted::rsx! { <div title=r#""double quotes!""#></div> }.render().into_inner(),
	r#"<div title='"double quotes!"'></div>"#,
);

[umajho]

Thank you for your efforts.

As a user, I'm completely fine with this API.

However, I’m a bit concerned it could make the project harder for you to maintain. For example, if you later introduce another toggleable feature (say, pretty_print), you would need 4 sets of macros: default (double-quoted + non-pretty), mod pretty (double-quoted + pretty), mod single_quoted (single-quoted + non-pretty), and mod single_quoted_pretty (single-quoted + pretty). The complexity grows even more as additional toggleable features are added.
IMO, since this feature doesn't change how things fundamentally work, it may not warrant separate APIs.

That said, it’s entirely your call. If you decide to implement it this way, I’ll happily use it as-is.