Adapt format specifier highlighting to support escaped squences and unicode identifiers

Author: ltentrup

crates/ra_ide/src/snapshots/highlight_strings.html

@@ -74,4 +74,9 @@
     <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal">, `</span><span class="attribute">{</span><span class="variable">name</span><span class="attribute">:</span><span class="attribute">&gt;</span><span class="numeric_literal">8</span><span class="attribute">.</span><span class="attribute">*</span><span class="attribute">}</span><span class="string_literal">` has 3 right-aligned characters"</span>, <span class="string_literal">"Hello"</span>, <span class="numeric_literal">3</span>, name=<span class="string_literal">"1234.56"</span>);
     <span class="macro">println!</span>(<span class="string_literal">"Hello {{}}"</span>);
     <span class="macro">println!</span>(<span class="string_literal">"{{ Hello"</span>);
+
+    <span class="macro">println!</span>(<span class="string_literal">r"Hello, </span><span class="attribute">{</span><span class="attribute">}</span><span class="string_literal">!"</span>, <span class="string_literal">"world"</span>);
+
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="variable">\x41</span><span class="attribute">}</span><span class="string_literal">"</span>, A = <span class="numeric_literal">92</span>);
+    <span class="macro">println!</span>(<span class="string_literal">"</span><span class="attribute">{</span><span class="variable">ничоси</span><span class="attribute">}</span><span class="string_literal">"</span>, ничоси = <span class="numeric_literal">92</span>);
 }</code></pre>

crates/ra_ide/src/syntax_highlighting.rs

@@ -245,28 +245,29 @@ pub(crate) fn highlight(
                 stack.push();
                 if is_format_string {
                     string.lex_format_specifier(|piece_range, kind| {
-                        let highlight = match kind {
-                            FormatSpecifier::Open
-                            | FormatSpecifier::Close
-                            | FormatSpecifier::Colon
-                            | FormatSpecifier::Fill
-                            | FormatSpecifier::Align
-                            | FormatSpecifier::Sign
-                            | FormatSpecifier::NumberSign
-                            | FormatSpecifier::DollarSign
-                            | FormatSpecifier::Dot
-                            | FormatSpecifier::Asterisk
-                            | FormatSpecifier::QuestionMark => HighlightTag::Attribute,
-                            FormatSpecifier::Integer | FormatSpecifier::Zero => {
-                                HighlightTag::NumericLiteral
-                            }
-                            FormatSpecifier::Identifier => HighlightTag::Local,
-                        };
-                        stack.add(HighlightedRange {
-                            range: piece_range + range.start(),
-                            highlight: highlight.into(),
-                            binding_hash: None,
-                        });
+                        if let Some(highlight) = highlight_format_specifier(kind) {
+                            stack.add(HighlightedRange {
+                                range: piece_range + range.start(),
+                                highlight: highlight.into(),
+                                binding_hash: None,
+                            });
+                        }
+                    });
+                }
+                stack.pop();
+            } else if let Some(string) =
+                element_to_highlight.as_token().cloned().and_then(ast::RawString::cast)
+            {
+                stack.push();
+                if is_format_string {
+                    string.lex_format_specifier(|piece_range, kind| {
+                        if let Some(highlight) = highlight_format_specifier(kind) {
+                            stack.add(HighlightedRange {
+                                range: piece_range + range.start(),
+                                highlight: highlight.into(),
+                                binding_hash: None,
+                            });
+                        }
                     });
                 }
                 stack.pop();
@@ -277,6 +278,24 @@ pub(crate) fn highlight(
     stack.flattened()
 }
 
+fn highlight_format_specifier(kind: FormatSpecifier) -> Option<HighlightTag> {
+    Some(match kind {
+        FormatSpecifier::Open
+        | FormatSpecifier::Close
+        | FormatSpecifier::Colon
+        | FormatSpecifier::Fill
+        | FormatSpecifier::Align
+        | FormatSpecifier::Sign
+        | FormatSpecifier::NumberSign
+        | FormatSpecifier::DollarSign
+        | FormatSpecifier::Dot
+        | FormatSpecifier::Asterisk
+        | FormatSpecifier::QuestionMark => HighlightTag::Attribute,
+        FormatSpecifier::Integer | FormatSpecifier::Zero => HighlightTag::NumericLiteral,
+        FormatSpecifier::Identifier => HighlightTag::Local,
+    })
+}
+
 fn macro_call_range(macro_call: &ast::MacroCall) -> Option<TextRange> {
     let path = macro_call.path()?;
     let name_ref = path.segment()?.name_ref()?;

crates/ra_ide/src/syntax_highlighting/tests.rs

@@ -223,6 +223,11 @@ fn main() {
     println!("{}, `{name:>8.*}` has 3 right-aligned characters", "Hello", 3, name="1234.56");
     println!("Hello {{}}");
     println!("{{ Hello");
+
+    println!(r"Hello, {}!", "world");
+
+    println!("{\x41}", A = 92);
+    println!("{ничоси}", ничоси = 92);
 }"#
         .trim(),
     );