fmt: format comments block & line comments

crates/squawk_fmt/src/comment.rs

@@ -1,5 +1,5 @@
 use rowan::Direction;
-use squawk_line_index::find_newline;
+use squawk_line_index::{UniversalNewlines, find_newline};
 use squawk_syntax::{SyntaxElement, SyntaxKind, SyntaxToken};
 use tiny_pretty::Doc;
 
@@ -8,7 +8,26 @@ pub(crate) fn is_line_comment(token: &SyntaxToken) -> bool {
 }
 
 pub(crate) fn build_comment<'a>(token: &SyntaxToken) -> Doc<'a> {
-    let line = |text: &str| Doc::text(text.trim_end_matches([' ', '\t']).to_string());
+    let align_stars = !is_line_comment(token)
+        && find_newline(token.text()).is_some()
+        && token
+            .text()
+            .universal_newlines()
+            .skip(1)
+            .all(|line| line.as_str().trim_start().starts_with('*'));
+    let line = |text: &str| {
+        let text = text.trim_end_matches([' ', '\t']);
+        if is_line_comment(token) {
+            if let Some(content) = text.strip_prefix("--") {
+                if !content.is_empty() && !content.starts_with(' ') && !content.starts_with('\t') {
+                    return Doc::text(format!("-- {content}"));
+                }
+            }
+        } else if align_stars && text.trim_start().starts_with('*') {
+            return Doc::text(format!(" {}", text.trim()));
+        }
+        Doc::text(text.to_string())
+    };
     let mut docs = vec![];
     let mut text = token.text();
     while let Some((position, line_ending)) = find_newline(text) {

crates/squawk_fmt/src/token_compare.rs

@@ -14,18 +14,46 @@ fn meaningful_tokens(text: &str) -> Vec<(TokenKind, &str)> {
     tokens
 }
 
+fn line_comments_equivalent(before: &str, after: &str) -> bool {
+    let before = before.trim_end_matches([' ', '\t']);
+    let after = after.trim_end_matches([' ', '\t']);
+    if before == after {
+        return true;
+    }
+
+    let Some(content) = before.strip_prefix("--") else {
+        return false;
+    };
+    if content.is_empty() || content.starts_with(' ') || content.starts_with('\t') {
+        return false;
+    }
+
+    after.strip_prefix("-- ") == Some(content)
+}
+
 fn tokens_equivalent(before: (TokenKind, &str), after: (TokenKind, &str)) -> bool {
     let (before_kind, before_text) = before;
     let (after_kind, after_text) = after;
 
     if before_kind == after_kind {
-        if matches!(
-            before_kind,
-            TokenKind::LineComment | TokenKind::BlockComment { .. }
-        ) {
+        if before_kind == TokenKind::LineComment {
+            return line_comments_equivalent(before_text, after_text);
+        }
+        if matches!(before_kind, TokenKind::BlockComment { .. }) {
             let normalize = |text: &str| {
+                let align_stars = text
+                    .universal_newlines()
+                    .skip(1)
+                    .all(|line| line.as_str().trim_start().starts_with('*'));
                 text.universal_newlines()
-                    .map(|line| line.as_str().trim_end_matches([' ', '\t']))
+                    .map(|line| {
+                        let line = line.as_str().trim_end_matches([' ', '\t']);
+                        if align_stars && line.trim_start().starts_with('*') {
+                            format!(" {}", line.trim())
+                        } else {
+                            line.to_string()
+                        }
+                    })
                     .collect::<Vec<_>>()
                     .join("\n")
             };

crates/squawk_fmt/tests/after/comments.snap

@@ -20,3 +20,25 @@ input_file: crates/squawk_fmt/tests/before/comments.sql
 -- we have a big gap here, but we should only output a couple lines at most
 
 /* end */
+
+/*
+ *
+ *
+ *
+ */
+select 1;
+
+/*
+*
+
+*
+*/
+select 1;
+
+/*
+ * text
+ */
+select 1;
+
+/*foo*/
+select 1;

crates/squawk_fmt/tests/before/comments.sql

@@ -4,7 +4,7 @@
  * 
  */
 
--- intentional new line follows, we should keep that
+--intentional new line follows, we should keep that
 
 /* bar */
 /* followed by another comment */
@@ -25,3 +25,25 @@
 
 
 /* end */
+
+/*
+*
+*
+*
+*/
+select 1;
+
+/*
+*
+
+*
+*/
+select 1;
+
+/*
+          * text
+          */
+select 1;
+
+/*foo*/
+select 1;