feat: support break and continue in for loops

Author: Madoshakalaka

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

@@ -130,10 +130,9 @@ impl ToTokens for HtmlFor {
 
         tokens.extend(quote!({
             let mut #acc = ::std::vec::Vec::<::yew::virtual_dom::VNode>::new();
-            ::std::iter::Iterator::for_each(
-                ::std::iter::IntoIterator::into_iter(#iter),
-                |#pat| { #(#let_stmts)* #alloc_opt; #(#body);* }
-            );
+            for #pat in #iter {
+                #(#let_stmts)* #alloc_opt; #(#body);*
+            }
             #vlist_gen
         }))
     }

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

@@ -52,6 +52,8 @@ pub enum HtmlType {
     If,
     For,
     Match,
+    Break,
+    Continue,
     Empty,
 }
 
@@ -64,6 +66,8 @@ pub enum HtmlTree {
     For(Box<HtmlFor>),
     Match(Box<HtmlMatch>),
     Node(Box<HtmlNode>),
+    Break(Token![break]),
+    Continue(Token![continue]),
     Empty,
 }
 
@@ -80,6 +84,8 @@ impl Parse for HtmlTree {
             HtmlType::If => Self::If(Box::new(input.parse()?)),
             HtmlType::For => Self::For(Box::new(input.parse()?)),
             HtmlType::Match => Self::Match(Box::new(input.parse()?)),
+            HtmlType::Break => Self::Break(input.parse()?),
+            HtmlType::Continue => Self::Continue(input.parse()?),
         })
     }
 }
@@ -113,6 +119,14 @@ impl HtmlTree {
             Some(HtmlType::For)
         } else if HtmlMatch::peek(cursor).is_some() {
             Some(HtmlType::Match)
+        } else if cursor.ident().map(|(i, _)| i == "break").unwrap_or(false) {
+            Some(HtmlType::Break)
+        } else if cursor
+            .ident()
+            .map(|(i, _)| i == "continue")
+            .unwrap_or(false)
+        {
+            Some(HtmlType::Continue)
         } else if input.peek(Token![<]) {
             let _lt: Token![<] = input.parse().ok()?;
 
@@ -163,6 +177,8 @@ impl ToTokens for HtmlTree {
             Self::For(block) => block.to_tokens(tokens),
             Self::Match(block) => block.to_tokens(tokens),
             Self::Node(node) => node.to_tokens(tokens),
+            Self::Break(token) => token.to_tokens(tokens),
+            Self::Continue(token) => token.to_tokens(tokens),
         }
     }
 }
@@ -428,7 +444,12 @@ impl HtmlChildrenTree {
                         HtmlNode::Expression(_) => None,
                     };
                 }
-                HtmlTree::If(_) | HtmlTree::For(_) | HtmlTree::Match(_) | HtmlTree::Empty => {
+                HtmlTree::If(_)
+                | HtmlTree::For(_)
+                | HtmlTree::Match(_)
+                | HtmlTree::Break(_)
+                | HtmlTree::Continue(_)
+                | HtmlTree::Empty => {
                     return Some(false);
                 }
             }

packages/yew-macro/tests/html_macro/for-fail.rs

@@ -10,10 +10,6 @@ fn main() {
         <span>{x}</span>
     }};
 
-    _ = ::yew::html!{for _ in 0 .. 10 {
-        <span>{break}</span>
-    }};
-
     _ = ::yew::html!{for _ in 0 .. 10 {
         <div key="duplicate" />
     }};

packages/yew-macro/tests/html_macro/for-fail.stderr

@@ -24,42 +24,31 @@ error: unexpected end of input, expected curly braces
 
 error: duplicate key for a node in a `for`-loop
        this will create elements with duplicate keys if the loop iterates more than once
-  --> tests/html_macro/for-fail.rs:18:18
+  --> tests/html_macro/for-fail.rs:14:18
    |
-18 |         <div key="duplicate" />
+14 |         <div key="duplicate" />
    |                  ^^^^^^^^^^^
 
 error: duplicate key for a node in a `for`-loop
        this will create elements with duplicate keys if the loop iterates more than once
-  --> tests/html_macro/for-fail.rs:22:19
+  --> tests/html_macro/for-fail.rs:18:19
    |
-22 |         <div key={smth::KEY} />
+18 |         <div key={smth::KEY} />
    |                   ^^^^
 
 error: unnecessary `<>...</>`. Children can be placed directly in the body
-  --> tests/html_macro/for-fail.rs:27:9
+  --> tests/html_macro/for-fail.rs:23:9
    |
-27 |         <><span>{"a"}</span><span>{"b"}</span></>
+23 |         <><span>{"a"}</span><span>{"b"}</span></>
    |         ^^
 
-error[E0267]: `break` inside of a closure
-  --> tests/html_macro/for-fail.rs:14:16
-   |
-13 |       _ = ::yew::html!{for _ in 0 .. 10 {
-   |  _________-
-14 | |         <span>{break}</span>
-   | |                ^^^^^ cannot `break` inside of a closure
-15 | |     }};
-   | |______- enclosing closure
-
 error[E0308]: mismatched types
  --> tests/html_macro/for-fail.rs:9:26
   |
 9 |     _ = ::yew::html!{for (x, y) in 0 .. 10 {
-  |                          ^^^^^^
+  |                          ^^^^^^    ------- this is an iterator with items of type `{integer}`
   |                          |
   |                          expected integer, found `(_, _)`
-  |                          expected due to this
   |
   = note: expected type `{integer}`
             found tuple `(_, _)`

packages/yew-macro/tests/html_macro/for-pass.rs

@@ -118,4 +118,24 @@ fn main() {
             <hr/>
         }
     };
+
+    // break in for loop
+    _ = ::yew::html!{
+        for i in 0..10 {
+            if i > 5 {
+                break
+            }
+            <span>{i}</span>
+        }
+    };
+
+    // continue in for loop
+    _ = ::yew::html!{
+        for i in 0..10 {
+            if i % 2 == 0 {
+                continue
+            }
+            <span>{i}</span>
+        }
+    };
 }