Add direct-er literals

Author: kirillsemyonkin

packages/yew-macro/src/props/prop.rs

@@ -6,7 +6,7 @@ use quote::{quote, quote_spanned, ToTokens};
 use syn::parse::{Parse, ParseBuffer, ParseStream};
 use syn::spanned::Spanned;
 use syn::token::Brace;
-use syn::{braced, Block, Expr, ExprBlock, ExprMacro, ExprPath, ExprRange, Stmt, Token};
+use syn::{braced, Block, Expr, ExprBlock, ExprMacro, ExprPath, ExprRange, Stmt, Token, LitStr, parse_quote};
 
 use crate::html_tree::HtmlDashedName;
 use crate::stringify::Stringify;
@@ -27,6 +27,12 @@ impl From<HtmlDashedName> for PropLabel {
     }
 }
 
+impl From<LitStr> for PropLabel {
+    fn from(value: LitStr) -> Self {
+        Self::Dynamic(parse_quote! { #value })
+    }
+}
+
 impl TryFrom<PropLabel> for HtmlDashedName {
     type Error = ();
 
@@ -100,7 +106,9 @@ impl Parse for Prop {
             .map(PropDirective::ApplyAsProperty)
             .ok();
         if input.peek(Brace) {
-            Self::parse_shorthand_or_dynamic_prop_assignment(input, directive)
+            Self::parse_shorthand_or_expr_dynamic_prop_assignment(input, directive)
+        } else if input.peek(LitStr) {
+            Self::parse_literal_dynamic_prop_assignment(input, directive)
         } else {
             Self::parse_prop_assignment(input, directive)
         }
@@ -114,7 +122,7 @@ impl Prop {
     ///
     /// Shorthand syntax only allows for labels with no hyphens,
     /// as it would otherwise create an ambiguity in the syntax.
-    fn parse_shorthand_or_dynamic_prop_assignment(
+    fn parse_shorthand_or_expr_dynamic_prop_assignment(
         input: ParseStream,
         directive: Option<PropDirective>,
     ) -> syn::Result<Self> {
@@ -163,6 +171,37 @@ impl Prop {
         })
     }
 
+    /// Parse a prop of the form `"label"={value}`
+    fn parse_literal_dynamic_prop_assignment(
+        input: ParseStream,
+        directive: Option<PropDirective>,
+    ) -> syn::Result<Self> {
+        let label = input.parse::<LitStr>()?;
+        let equals = input.parse::<Token![=]>().map_err(|_| {
+            let display = label.stringify();
+            syn::Error::new_spanned(
+                &label,
+                format!(
+                    "`{display}` doesn't have a value. (hint: set the value to `true` or `false` \
+                     for boolean attributes)"
+                ),
+            )
+        })?;
+        if input.is_empty() {
+            return Err(syn::Error::new_spanned(
+                equals,
+                "expected an expression following this equals sign",
+            ));
+        }
+
+        let value = parse_prop_value(input)?;
+        Ok(Self {
+            label: label.into(),
+            value,
+            directive,
+        })
+    }
+
     /// Parse a prop of the form `label={value}`
     fn parse_prop_assignment(
         input: ParseStream,

packages/yew-macro/tests/html_macro/dyn-prop-fail.rs

@@ -58,10 +58,13 @@ impl ::yew::Component for Simple {
 pub struct Fail;
 
 fn main() {
-    _ = ::yew::html! { <span { Fail }={ "" } /> };
-
     let dyn_prop = || Fail;
+
+    _ = ::yew::html! { <span { Fail }={ "" } /> };
     _ = ::yew::html! { <span { dyn_prop() }={ "" } /> };
 
-    _ = ::yew::html! { <Simple { "test" }={ "" } /> }
+    _ = ::yew::html! { <Simple "test"="" /> };
+    _ = ::yew::html! { <Simple "test"={ "" } /> };
+    _ = ::yew::html! { <Simple { "test" }={ "" } /> };
+    _ = ::yew::html! { <Simple { dyn_prop() }={ "" } /> };
 }

packages/yew-macro/tests/html_macro/dyn-prop-fail.stderr

@@ -1,13 +1,31 @@
 error: expected a valid Rust identifier
-  --> tests/html_macro/dyn-prop-fail.rs:66:34
+  --> tests/html_macro/dyn-prop-fail.rs:66:32
    |
-66 |     _ = ::yew::html! { <Simple { "test" }={ "" } /> }
+66 |     _ = ::yew::html! { <Simple "test"="" /> };
+   |                                ^^^^^^
+
+error: expected a valid Rust identifier
+  --> tests/html_macro/dyn-prop-fail.rs:67:32
+   |
+67 |     _ = ::yew::html! { <Simple "test"={ "" } /> };
+   |                                ^^^^^^
+
+error: expected a valid Rust identifier
+  --> tests/html_macro/dyn-prop-fail.rs:68:34
+   |
+68 |     _ = ::yew::html! { <Simple { "test" }={ "" } /> };
    |                                  ^^^^^^
 
+error: expected a valid Rust identifier
+  --> tests/html_macro/dyn-prop-fail.rs:69:34
+   |
+69 |     _ = ::yew::html! { <Simple { dyn_prop() }={ "" } /> };
+   |                                  ^^^^^^^^^^
+
 error[E0277]: the trait bound `implicit_clone::unsync::IString: From<Fail>` is not satisfied
-  --> tests/html_macro/dyn-prop-fail.rs:61:9
+  --> tests/html_macro/dyn-prop-fail.rs:63:9
    |
-61 |     _ = ::yew::html! { <span { Fail }={ "" } /> };
+63 |     _ = ::yew::html! { <span { Fail }={ "" } /> };
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `From<Fail>` is not implemented for `implicit_clone::unsync::IString`
    |
    = help: the following other types implement trait `From<T>`:

packages/yew-macro/tests/html_macro/dyn-prop-pass.rs

@@ -43,6 +43,8 @@ fn main() {
     // but valid html! (any checks can happen only during runtime)
 
     // literal
+    _ = ::yew::html! { <span "hx-on:click"="alert('Clicked!')" /> };
+    _ = ::yew::html! { <span "hx-on:click"="alert('Clicked!')" "hx-on:click"="alert('Clicked!')" /> };
     _ = ::yew::html! { <span { "hx-on:click" }={ "alert('Clicked!')" } /> };
     _ = ::yew::html! { <span { "hx-on:click" }={ "alert('Clicked!')" } { "hx-on:click" }={ "alert('Clicked!')" } /> };