feat: Highlight and prioritize code definitions in grep results

crates/fff-core/src/grep.rs

@@ -1363,6 +1363,25 @@ fn collect_grep_results<'a>(
         }
     }
 
+    // Prioritize definition matches within each file while preserving
+    // contiguous per-file grouping for downstream renderers.
+    // A global sort would split matches from the same file into non-contiguous
+    // blocks, causing duplicate file headers in the Lua renderer.
+    if options.classify_definitions {
+        let mut start = 0;
+        while start < all_matches.len() {
+            let file_index = all_matches[start].file_index;
+            let mut end = start + 1;
+            while end < all_matches.len() && all_matches[end].file_index == file_index {
+                end += 1;
+            }
+            crate::sort_buffer::sort_by_key_with_buffer(&mut all_matches[start..end], |m| {
+                !m.is_definition
+            });
+            start = end;
+        }
+    }
+
     // If no file had any match, we searched the entire slice.
     if result_files.is_empty() {
         files_consumed = files_to_search_len;
@@ -2396,6 +2415,70 @@ mod tests {
             "Single pattern should find 1 match"
         );
 
+        // Test that classify_definitions sorts defs first within each file group
+        // without breaking contiguous per-file ordering.
+        let options_with_defs = super::GrepSearchOptions {
+            classify_definitions: true,
+            ..options.clone()
+        };
+        // file1 has: "pub enum GrepMode" (def), "pub struct GrepMatch" (def)
+        // file2 has: "struct PlainTextMatcher" (def)
+        // Search for both files using a pattern that hits non-def lines too.
+        let result_defs = super::multi_grep_search(
+            &files,
+            &["pub"],
+            &[],
+            &options_with_defs,
+            &ContentCacheBudget::unlimited(),
+            None,
+            None,
+            None,
+        );
+        // All matches for a given file must be contiguous (no interleaving).
+        if !result_defs.matches.is_empty() {
+            let mut last_file = result_defs.matches[0].file_index;
+            let mut seen_files = std::collections::HashSet::new();
+            seen_files.insert(last_file);
+            for m in result_defs.matches.iter().skip(1) {
+                if m.file_index != last_file {
+                    assert!(
+                        !seen_files.contains(&m.file_index),
+                        "classify_definitions broke file contiguity: file {} appeared non-contiguously",
+                        m.file_index
+                    );
+                    seen_files.insert(m.file_index);
+                    last_file = m.file_index;
+                }
+            }
+        }
+        // Within each file group, definition matches must precede non-definition matches.
+        {
+            let mut i = 0;
+            while i < result_defs.matches.len() {
+                let file_index = result_defs.matches[i].file_index;
+                let group_start = i;
+                while i < result_defs.matches.len()
+                    && result_defs.matches[i].file_index == file_index
+                {
+                    i += 1;
+                }
+                let group = &result_defs.matches[group_start..i];
+                // Definitions should not appear after a non-definition in the same file.
+                let mut saw_non_def = false;
+                for m in group {
+                    if !m.is_definition {
+                        saw_non_def = true;
+                    } else {
+                        assert!(
+                            !saw_non_def,
+                            "classify_definitions: definition appeared after non-definition in file {}",
+                            file_index
+                        );
+                    }
+                }
+            }
+        }
+
         // Test with empty patterns
         let result3 = super::multi_grep_search(
             &files,

crates/fff-nvim/src/lib.rs

@@ -280,6 +280,7 @@ pub fn live_grep(
         smart_case,
         grep_mode,
         time_budget_ms,
+        classify_definitions,
         trim_whitespace,
     ): (
         String,
@@ -315,7 +316,7 @@ pub fn live_grep(
         time_budget_ms: time_budget_ms.unwrap_or(0),
         before_context: 0,
         after_context: 0,
-        classify_definitions: false,
+        classify_definitions: classify_definitions.unwrap_or(false),
         trim_whitespace: trim_whitespace.unwrap_or(false),
     };
 

crates/fff-nvim/src/lua_types.rs

@@ -141,6 +141,7 @@ impl IntoLua for GrepResultLua<'_> {
             item.set("col", m.col)?;
             item.set("byte_offset", m.byte_offset)?;
             item.set("line_content", m.line_content.as_str())?;
+            item.set("is_definition", m.is_definition)?;
 
             // Match byte ranges within line_content
             let ranges = lua.create_table()?;

lua/fff/conf.lua

@@ -54,6 +54,7 @@ local M = {}
 --- @field smart_case boolean
 --- @field time_budget_ms number
 --- @field modes string[]
+--- @field classify_definitions boolean
 --- @field trim_whitespace boolean
 
 --- @class FffConfig
@@ -333,6 +334,7 @@ local function init()
       smart_case = true, -- Case-insensitive unless query has uppercase
       time_budget_ms = 150, -- Max search time in ms per call (prevents UI freeze, 0 = no limit)
       modes = { 'plain', 'regex', 'fuzzy' }, -- Available grep modes and their cycling order
+      classify_definitions = false, -- Mark definition lines like fn/struct/class
       trim_whitespace = false, -- Strip leading whitespace from matched lines (useful for cleaner display)
     },
   }

lua/fff/grep/grep_renderer.lua

@@ -47,6 +47,7 @@ end
 local function render_match_line(item, ctx)
   local location = string.format(':%d:%d', item.line_number or 0, (item.col or 0) + 1)
   local separator = '  '
+
   -- vim.json.decode may return Blobs for strings with NUL bytes; coerce to string.
   local raw_content = item.line_content
   if type(raw_content) ~= 'string' then raw_content = raw_content and tostring(raw_content) or '' end
@@ -193,6 +194,15 @@ local function apply_match_highlights(item, ctx, item_idx, buf, ns_id, row, line
       })
     end
   end
+
+  -- 7. Definition indicator as virtual text
+  if item.is_definition then
+    pcall(vim.api.nvim_buf_set_extmark, buf, ns_id, row, 0, {
+      virt_text = { { ' [def]', config.hl.combo_header or 'Number' } },
+      virt_text_pos = 'right_align',
+      priority = 250,
+    })
+  end
 end
 
 --- Render a single item's lines (called by list_renderer's generate_item_lines).

lua/fff/grep/init.lua

@@ -34,6 +34,7 @@ function M.search(query, file_offset, page_size, config, grep_mode)
     conf.smart_case,
     grep_mode or 'plain',
     conf.time_budget_ms,
+    conf.classify_definitions,
     conf.trim_whitespace
   )
   return last_result