From 66d08e4f729e9935f346e43ffe84a446004841db Mon Sep 17 00:00:00 2001
From: Wilfred Hughes <me@wilfred.me.uk>
Date: Fri, 30 Jun 2023 08:48:12 -0700
Subject: [PATCH] WIP store probably_punctuation on unchanged edges

---
 sample_files/comma_and_comment_after.js  |  1 +
 sample_files/comma_and_comment_before.js |  1 +
 src/diff/dijkstra.rs                     |  4 ++++
 src/diff/graph.rs                        | 20 ++++++++++++++++++--
 4 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 sample_files/comma_and_comment_after.js
 create mode 100644 sample_files/comma_and_comment_before.js

diff --git a/sample_files/comma_and_comment_after.js b/sample_files/comma_and_comment_after.js
new file mode 100644
index 0000000000..8987b718a0
--- /dev/null
+++ b/sample_files/comma_and_comment_after.js
@@ -0,0 +1 @@
+funName(1 /* kinda like bar */ , /* foo */)
diff --git a/sample_files/comma_and_comment_before.js b/sample_files/comma_and_comment_before.js
new file mode 100644
index 0000000000..859e9fe38a
--- /dev/null
+++ b/sample_files/comma_and_comment_before.js
@@ -0,0 +1 @@
+funName(1 /* foo */ , /* bar */)
diff --git a/src/diff/dijkstra.rs b/src/diff/dijkstra.rs
index 96e78372e6..9f84b1fa6f 100644
--- a/src/diff/dijkstra.rs
+++ b/src/diff/dijkstra.rs
@@ -282,6 +282,7 @@ mod tests {
         assert_eq!(
             actions,
             vec![UnchangedNode {
+                probably_punctuation: false,
                 depth_difference: 0
             }]
         );
@@ -423,9 +424,11 @@ mod tests {
                 EnterNovelDelimiterRHS { contiguous: false },
                 EnterNovelDelimiterLHS { contiguous: false },
                 UnchangedNode {
+                    probably_punctuation: false,
                     depth_difference: 0
                 },
                 UnchangedNode {
+                    probably_punctuation: false,
                     depth_difference: 0
                 },
             ],
@@ -459,6 +462,7 @@ mod tests {
             actions,
             vec![
                 UnchangedNode {
+                    probably_punctuation: false,
                     depth_difference: 0
                 },
                 NovelAtomLHS {
diff --git a/src/diff/graph.rs b/src/diff/graph.rs
index 89ce09b190..6f321dd49b 100644
--- a/src/diff/graph.rs
+++ b/src/diff/graph.rs
@@ -276,6 +276,7 @@ impl<'s, 'b> Vertex<'s, 'b> {
 pub enum Edge {
     UnchangedNode {
         depth_difference: u32,
+        probably_punctuation: bool,
     },
     EnterUnchangedDelimiter {
         depth_difference: u32,
@@ -307,7 +308,10 @@ impl Edge {
     pub fn cost(self) -> u32 {
         match self {
             // Matching nodes is always best.
-            UnchangedNode { depth_difference } => min(40, depth_difference + 1),
+            UnchangedNode {
+                depth_difference,
+                probably_punctuation,
+            } => min(40, depth_difference + 1) + if probably_punctuation { 2000 } else { 0 },
             // Matching an outer delimiter is good.
             EnterUnchangedDelimiter { depth_difference } => 100 + min(40, depth_difference),
 
@@ -406,6 +410,13 @@ fn looks_like_punctuation(content: &str) -> bool {
     content == "," || content == ";" || content == "."
 }
 
+fn looks_like_punctuation_atom(node: &Syntax) -> bool {
+    match node {
+        Syntax::Atom { content, .. } => content == "," || content == ";" || content == ".",
+        _ => false,
+    }
+}
+
 /// Pop as many parents of `lhs_node` and `rhs_node` as
 /// possible. Return the new syntax nodes and parents.
 fn pop_all_parents<'s>(
@@ -493,6 +504,8 @@ pub fn get_set_neighbours<'s, 'b>(
                 - rhs_syntax.num_ancestors() as i32)
                 .unsigned_abs();
 
+            let probably_punctuation = looks_like_punctuation_atom(lhs_syntax);
+
             // Both nodes are equal, the happy case.
             let (lhs_syntax, rhs_syntax, lhs_parent_id, rhs_parent_id, parents) = pop_all_parents(
                 lhs_syntax.next_sibling(),
@@ -503,7 +516,10 @@ pub fn get_set_neighbours<'s, 'b>(
             );
 
             res.push((
-                UnchangedNode { depth_difference },
+                UnchangedNode {
+                    depth_difference,
+                    probably_punctuation,
+                },
                 allocate_if_new(
                     Vertex {
                         neighbours: RefCell::new(None),