From 083986030e2a81c1135321f89e0984564ac73c41 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Sun, 10 Jan 2021 11:57:17 +0300
Subject: Replace state with function

---
 crates/ide/src/syntax_highlighting/format.rs | 82 ++++++++++++----------------
 1 file changed, 36 insertions(+), 46 deletions(-)

(limited to 'crates/ide/src/syntax_highlighting/format.rs')

diff --git a/crates/ide/src/syntax_highlighting/format.rs b/crates/ide/src/syntax_highlighting/format.rs
index d807ad0ad..a74ca844b 100644
--- a/crates/ide/src/syntax_highlighting/format.rs
+++ b/crates/ide/src/syntax_highlighting/format.rs
@@ -1,60 +1,48 @@
 //! Syntax highlighting for format macro strings.
 use syntax::{
     ast::{self, FormatSpecifier, HasFormatSpecifier},
-    AstNode, AstToken, SyntaxElement, SyntaxKind, SyntaxNode, TextRange,
+    AstNode, AstToken, TextRange,
 };
 
-use crate::{HlRange, HlTag, SymbolKind};
+use crate::{syntax_highlighting::highlights::Highlights, HlRange, HlTag, SymbolKind};
 
-use super::highlights::Highlights;
+pub(super) fn highlight_format_string(
+    stack: &mut Highlights,
+    string: &ast::String,
+    range: TextRange,
+) {
+    if is_format_string(string).is_none() {
+        return;
+    }
 
-#[derive(Default)]
-pub(super) struct FormatStringHighlighter {
-    format_string: Option<SyntaxElement>,
+    string.lex_format_specifier(|piece_range, kind| {
+        if let Some(highlight) = highlight_format_specifier(kind) {
+            stack.add(HlRange {
+                range: piece_range + range.start(),
+                highlight: highlight.into(),
+                binding_hash: None,
+            });
+        }
+    });
 }
 
-impl FormatStringHighlighter {
-    pub(super) fn check_for_format_string(&mut self, parent: &SyntaxNode) {
-        // Check if macro takes a format string and remember it for highlighting later.
-        // The macros that accept a format string expand to a compiler builtin macros
-        // `format_args` and `format_args_nl`.
-        if let Some(name) = parent
-            .parent()
-            .and_then(ast::MacroCall::cast)
-            .and_then(|mc| mc.path())
-            .and_then(|p| p.segment())
-            .and_then(|s| s.name_ref())
-        {
-            match name.text().as_str() {
-                "format_args" | "format_args_nl" => {
-                    self.format_string = parent
-                        .children_with_tokens()
-                        .filter(|t| t.kind() != SyntaxKind::WHITESPACE)
-                        .nth(1)
-                        .filter(|e| ast::String::can_cast(e.kind()))
-                }
-                _ => {}
-            }
-        }
+fn is_format_string(string: &ast::String) -> Option<()> {
+    let parent = string.syntax().parent();
+
+    let name = parent.parent().and_then(ast::MacroCall::cast)?.path()?.segment()?.name_ref()?;
+    if !matches!(name.text().as_str(), "format_args" | "format_args_nl") {
+        return None;
     }
-    pub(super) fn highlight_format_string(
-        &self,
-        stack: &mut Highlights,
-        string: &impl HasFormatSpecifier,
-        range: TextRange,
-    ) {
-        if self.format_string.as_ref() == Some(&SyntaxElement::from(string.syntax().clone())) {
-            string.lex_format_specifier(|piece_range, kind| {
-                if let Some(highlight) = highlight_format_specifier(kind) {
-                    stack.add(HlRange {
-                        range: piece_range + range.start(),
-                        highlight: highlight.into(),
-                        binding_hash: None,
-                    });
-                }
-            });
-        }
+
+    let first_literal = parent
+        .children_with_tokens()
+        .filter_map(|it| it.as_token().cloned().and_then(ast::String::cast))
+        .next()?;
+    if &first_literal != string {
+        return None;
     }
+
+    Some(())
 }
 
 fn highlight_format_specifier(kind: FormatSpecifier) -> Option<HlTag> {
@@ -70,7 +58,9 @@ fn highlight_format_specifier(kind: FormatSpecifier) -> Option<HlTag> {
         | FormatSpecifier::Dot
         | FormatSpecifier::Asterisk
         | FormatSpecifier::QuestionMark => HlTag::FormatSpecifier,
+
         FormatSpecifier::Integer | FormatSpecifier::Zero => HlTag::NumericLiteral,
+
         FormatSpecifier::Identifier => HlTag::Symbol(SymbolKind::Local),
     })
 }
-- 
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