Will now lint incorrect quote characters

lt-core/src/document.rs

@@ -28,7 +28,7 @@ impl Document {
         doc
     }
 
-    fn iter_quote_indices(&self) -> impl Iterator<Item = usize> + '_ {
+    pub fn iter_quote_indices(&self) -> impl Iterator<Item = usize> + '_ {
         self.tokens.iter().enumerate().filter_map(|(idx, token)| {
             if let TokenKind::Punctuation(Punctuation::Quote(_)) = &token.kind {
                 Some(idx)
@@ -38,6 +38,10 @@ impl Document {
         })
     }
 
+    pub fn iter_quotes(&self) -> impl Iterator<Item = Token> + '_ {
+        self.iter_quote_indices().map(|idx| self.tokens[idx])
+    }
+
     /// Searches for quotation marks and fills the [`Punctuation::Quote::twin_loc`] field.
     /// This is on a best effort basis.
     ///

lt-core/src/linting/lint.rs

@@ -15,6 +15,7 @@ pub enum LintKind {
     Spelling,
     Capitalization,
     UnmatchedQuote,
+    WrongQuotes,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]

lt-core/src/linting/mod.rs

@@ -2,6 +2,7 @@ mod lint;
 mod sentence_capitalization;
 mod spell_check;
 mod unclosed_quotes;
+mod wrong_quotes;
 
 pub use lint::{Lint, LintKind, Suggestion};
 
@@ -12,10 +13,11 @@ use self::lint::Linter;
 pub fn all_linters(document: &Document) -> Vec<Lint> {
     let mut lints = Vec::new();
 
-    let linters: [Linter; 3] = [
+    let linters: [Linter; 4] = [
         spell_check::spell_check,
         sentence_capitalization::sentence_capitalization_lint,
         unclosed_quotes::unclosed_quotes,
+        wrong_quotes::wrong_quotes,
     ];
 
     for linter in linters {

lt-core/src/linting/wrong_quotes.rs

@@ -0,0 +1,33 @@
+use crate::{
+    document::Document, parsing::Quote, Lint, LintKind, Punctuation, Suggestion, Token, TokenKind,
+};
+
+pub fn wrong_quotes(document: &Document) -> Vec<Lint> {
+    document
+        .iter_quote_indices()
+        .zip(document.iter_quotes())
+        .filter_map(|(quote_idx, quote_token)| lint_quote(document, quote_idx, quote_token))
+        .collect()
+}
+
+fn lint_quote(document: &Document, quote_idx: usize, quote_token: Token) -> Option<Lint> {
+    let quote = quote_token.kind.as_quote().unwrap();
+
+    let twin_loc = quote.twin_loc?;
+    let is_left = twin_loc > quote_idx;
+
+    let quote_char = *document.get_span_content(quote_token.span).first()?;
+
+    let should_be = if is_left { '“' } else { '”' };
+
+    if quote_char != should_be {
+        Some(Lint {
+            span: quote_token.span,
+            lint_kind: LintKind::WrongQuotes,
+            suggestions: vec![Suggestion::ReplaceWith(vec![should_be])],
+            message: "Use the better-formatted quote character.".to_string(),
+        })
+    } else {
+        None
+    }
+}