yew-macro:

    - Removed most of `.to_string()` calls
    - Factored out the check for a component-like name

Author: its-the-shrimp

Cargo.lock

@@ -28,6 +28,7 @@ rustversion.workspace = true
 trybuild = { workspace = true }
 yew = { path = "../yew" }
 implicit-clone = { workspace = true }
+rand = "0.9"
 
 [lints]
 workspace = true

packages/yew-macro/Cargo.toml

@@ -9,6 +9,7 @@ use syn::{
 };
 
 use crate::hook::BodyRewriter;
+use crate::DisplayExt;
 
 #[derive(Clone)]
 pub struct FunctionComponent {
@@ -157,29 +158,25 @@ impl FunctionComponent {
     fn filter_attrs_for_component_struct(&self) -> Vec<Attribute> {
         self.attrs
             .iter()
-            .filter_map(|m| {
+            .filter(|m| {
                 m.path()
                     .get_ident()
-                    .and_then(|ident| match ident.to_string().as_str() {
-                        "doc" | "allow" => Some(m.clone()),
-                        _ => None,
-                    })
+                    .is_some_and(|ident| (ident.eq_str("doc") || ident.eq_str("allow")))
             })
+            .cloned()
             .collect()
     }
 
     /// Filters attributes that should be copied to the component impl block.
     fn filter_attrs_for_component_impl(&self) -> Vec<Attribute> {
         self.attrs
             .iter()
-            .filter_map(|m| {
+            .filter(|m| {
                 m.path()
                     .get_ident()
-                    .and_then(|ident| match ident.to_string().as_str() {
-                        "allow" => Some(m.clone()),
-                        _ => None,
-                    })
+                    .is_some_and(|ident| ident.eq_str("allow"))
             })
+            .cloned()
             .collect()
     }
 

packages/yew-macro/src/function_component.rs

@@ -8,6 +8,8 @@ use syn::{
     ExprMatch, ExprWhile, Ident, Item,
 };
 
+use crate::DisplayExt;
+
 #[derive(Debug)]
 pub struct BodyRewriter {
     branch_lock: Arc<Mutex<()>>,
@@ -43,7 +45,7 @@ impl VisitMut for BodyRewriter {
         // Only rewrite hook calls.
         if let Expr::Path(ref m) = &*i.func {
             if let Some(m) = m.path.segments.last().as_ref().map(|m| &m.ident) {
-                if m.to_string().starts_with("use_") {
+                if m.starts_with("use_") {
                     if self.is_branched() {
                         emit_error!(
                             m,
@@ -69,7 +71,7 @@ impl VisitMut for BodyRewriter {
         match &mut *i {
             Expr::Macro(m) => {
                 if let Some(ident) = m.mac.path.segments.last().as_ref().map(|m| &m.ident) {
-                    if ident.to_string().starts_with("use_") {
+                    if ident.starts_with("use_") {
                         if self.is_branched() {
                             emit_error!(
                                 ident,

packages/yew-macro/src/hook/body.rs

@@ -15,6 +15,8 @@ mod signature;
 pub use body::BodyRewriter;
 use signature::HookSignature;
 
+use crate::DisplayExt;
+
 #[derive(Clone)]
 pub struct HookFn {
     inner: ItemFn,
@@ -42,7 +44,7 @@ impl Parse for HookFn {
             emit_error!(sig.unsafety, "unsafe functions can't be hooks");
         }
 
-        if !sig.ident.to_string().starts_with("use_") {
+        if !sig.ident.starts_with("use_") {
             emit_error!(sig.ident, "hooks must have a name starting with `use_`");
         }
 

packages/yew-macro/src/hook/mod.rs

@@ -1,3 +1,5 @@
+use std::fmt::{Display, Write};
+
 use proc_macro2::Span;
 use quote::{quote, quote_spanned, ToTokens};
 use syn::parse::discouraged::Speculative;
@@ -9,6 +11,41 @@ use super::{HtmlChildrenTree, TagTokens};
 use crate::is_ide_completion;
 use crate::props::ComponentProps;
 
+/// Returns `true` if `s` looks like a component name
+pub fn is_component_name(s: impl Display) -> bool {
+    struct X {
+        is_ide_completion: bool,
+        empty: bool,
+    }
+
+    impl Write for X {
+        fn write_str(&mut self, chunk: &str) -> std::fmt::Result {
+            if self.empty {
+                self.empty = chunk.is_empty();
+                if !self.is_ide_completion
+                    && chunk
+                        .bytes()
+                        .next()
+                        .is_some_and(|b| !b.is_ascii_uppercase())
+                {
+                    return Err(std::fmt::Error);
+                }
+            }
+            chunk
+                .bytes()
+                .any(|b| b.is_ascii_uppercase())
+                .then_some(())
+                .ok_or(std::fmt::Error)
+        }
+    }
+
+    let mut writer = X {
+        is_ide_completion: is_ide_completion(),
+        empty: true,
+    };
+    write!(writer, "{s}").is_ok_and(|_| !writer.empty)
+}
+
 pub struct HtmlComponent {
     ty: Type,
     pub props: ComponentProps,

packages/yew-macro/src/html_tree/html_component.rs

@@ -9,7 +9,7 @@ use syn::spanned::Spanned;
 use syn::{LitStr, Token};
 
 use crate::stringify::Stringify;
-use crate::{non_capitalized_ascii, Peek};
+use crate::{DisplayExt, Peek};
 
 #[derive(Clone, PartialEq, Eq)]
 pub struct HtmlDashedName {
@@ -18,17 +18,6 @@ pub struct HtmlDashedName {
 }
 
 impl HtmlDashedName {
-    /// Checks if this name is equal to the provided item (which can be anything implementing
-    /// `Into<String>`).
-    pub fn eq_ignore_ascii_case<S>(&self, other: S) -> bool
-    where
-        S: Into<String>,
-    {
-        let mut s = other.into();
-        s.make_ascii_lowercase();
-        s == self.to_ascii_lowercase_string()
-    }
-
     pub fn to_ascii_lowercase_string(&self) -> String {
         let mut s = self.to_string();
         s.make_ascii_lowercase();
@@ -53,7 +42,7 @@ impl fmt::Display for HtmlDashedName {
 impl Peek<'_, Self> for HtmlDashedName {
     fn peek(cursor: Cursor) -> Option<(Self, Cursor)> {
         let (name, cursor) = cursor.ident()?;
-        if !non_capitalized_ascii(&name.to_string()) {
+        if !name.is_non_capitalized_ascii() {
             return None;
         }
 

packages/yew-macro/src/html_tree/html_dashed_name.rs

@@ -9,7 +9,7 @@ use syn::{Expr, Ident, Lit, LitStr, Token};
 use super::{HtmlChildrenTree, HtmlDashedName, TagTokens};
 use crate::props::{ElementProps, Prop, PropDirective};
 use crate::stringify::{Stringify, Value};
-use crate::{is_ide_completion, non_capitalized_ascii, Peek, PeekValue};
+use crate::{is_ide_completion, DisplayExt, Peek, PeekValue};
 
 fn is_normalised_element_name(name: &str) -> bool {
     match name {
@@ -672,13 +672,13 @@ impl PeekValue<TagKey> for HtmlElementOpen {
         let (tag_key, cursor) = TagName::peek(cursor)?;
         if let TagKey::Lit(name) = &tag_key {
             // Avoid parsing `<key=[...]>` as an element. It needs to be parsed as an `HtmlList`.
-            if name.to_string() == "key" {
+            if name.eq_str("key") {
                 let (punct, _) = cursor.punct()?;
                 // ... unless it isn't followed by a '='. `<key></key>` is a valid element!
                 if punct.as_char() == '=' {
                     return None;
                 }
-            } else if !non_capitalized_ascii(&name.to_string()) {
+            } else if !name.is_non_capitalized_ascii() {
                 return None;
             }
         }
@@ -747,7 +747,7 @@ impl PeekValue<TagKey> for HtmlElementClose {
         }
 
         let (tag_key, cursor) = TagName::peek(cursor)?;
-        if matches!(&tag_key, TagKey::Lit(name) if !non_capitalized_ascii(&name.to_string())) {
+        if matches!(&tag_key, TagKey::Lit(name) if !name.is_non_capitalized_ascii()) {
             return None;
         }
 

packages/yew-macro/src/html_tree/html_element.rs

@@ -7,7 +7,7 @@ use syn::Lit;
 
 use super::ToNodeIterator;
 use crate::stringify::Stringify;
-use crate::PeekValue;
+use crate::{DisplayExt, PeekValue};
 
 pub enum HtmlNode {
     Literal(Box<Lit>),
@@ -44,10 +44,7 @@ impl PeekValue<()> for HtmlNode {
     fn peek(cursor: Cursor) -> Option<()> {
         cursor.literal().map(|_| ()).or_else(|| {
             let (ident, _) = cursor.ident()?;
-            match ident.to_string().as_str() {
-                "true" | "false" => Some(()),
-                _ => None,
-            }
+            (ident.eq_str("true") || ident.eq_str("false")).then_some(())
         })
     }
 }

packages/yew-macro/src/html_tree/html_node.rs

@@ -7,6 +7,7 @@ use syn::spanned::Spanned;
 use super::html_element::{HtmlElement, TagName};
 use super::HtmlTree;
 use crate::props::{ElementProps, Prop};
+use crate::DisplayExt;
 
 /// Lints HTML elements to check if they are well formed. If the element is not well-formed, then
 /// use `proc-macro-error` (and the `emit_warning!` macro) to produce a warning. At present, these
@@ -50,7 +51,7 @@ fn get_attribute<'a>(props: &'a ElementProps, name: &str) -> Option<&'a Prop> {
     props
         .attributes
         .iter()
-        .find(|item| item.label.eq_ignore_ascii_case(name))
+        .find(|item| item.label.eq_str_ignore_ascii_case(name))
 }
 
 /// Lints to check if anchor (`<a>`) tags have valid `href` attributes defined.
@@ -59,7 +60,7 @@ pub struct AHrefLint;
 impl Lint for AHrefLint {
     fn lint(element: &HtmlElement) {
         if let TagName::Lit(ref tag_name) = element.name {
-            if !tag_name.eq_ignore_ascii_case("a") {
+            if !tag_name.eq_str_ignore_ascii_case("a") {
                 return;
             };
             if let Some(prop) = get_attribute(&element.props, "href") {
@@ -81,7 +82,7 @@ impl Lint for AHrefLint {
                 };
             } else {
                 emit_warning!(
-                    quote::quote! {#tag_name}.span(),
+                    tag_name.span(),
                     "All `<a>` elements should have a `href` attribute. This makes it possible \
                         for assistive technologies to correctly interpret what your links point to. \
                         https://developer.mozilla.org/en-US/docs/Learn/Accessibility/HTML#more_on_links"
@@ -97,7 +98,7 @@ pub struct ImgAltLint;
 impl Lint for ImgAltLint {
     fn lint(element: &HtmlElement) {
         if let super::html_element::TagName::Lit(ref tag_name) = element.name {
-            if !tag_name.eq_ignore_ascii_case("img") {
+            if !tag_name.eq_str_ignore_ascii_case("img") {
                 return;
             };
             if get_attribute(&element.props, "alt").is_none() {