diff options
Diffstat (limited to 'helix-core/src/syntax.rs')
| -rw-r--r-- | helix-core/src/syntax.rs | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/helix-core/src/syntax.rs b/helix-core/src/syntax.rs index 93bd7fe9..b567a8ab 100644 --- a/helix-core/src/syntax.rs +++ b/helix-core/src/syntax.rs @@ -354,24 +354,25 @@ impl<'a> CapturedNode<'a> { } } -/// The number of matches a TS cursor can at once to avoid performance problems for medium to large files. -/// Set with `set_match_limit`. -/// Using such a limit means that we lose valid captures in, so there is fundamentally a tradeoff here. +/// The maximum number of in-progress matches a TS cursor can consider at once. +/// This is set to a constant in order to avoid performance problems for medium to large files. Set with `set_match_limit`. +/// Using such a limit means that we lose valid captures, so there is fundamentally a tradeoff here. /// /// /// Old tree sitter versions used a limit of 32 by default until this limit was removed in version `0.19.5` (must now be set manually). /// However, this causes performance issues for medium to large files. /// In helix, this problem caused treesitter motions to take multiple seconds to complete in medium-sized rust files (3k loc). +/// +/// /// Neovim also encountered this problem and reintroduced this limit after it was removed upstream /// (see <https://github.com/neovim/neovim/issues/14897> and <https://github.com/neovim/neovim/pull/14915>). /// The number used here is fundamentally a tradeoff between breaking some obscure edge cases and performance. /// /// -/// A value of 64 was chosen because neovim uses that value. -/// Neovim chose this value somewhat arbitrarily (<https://github.com/neovim/neovim/pull/18397>) adjusting it whenever issues occur in practice. -/// However this value has been in use for a long time and due to the large userbase of neovim it is probably a good choice. -/// If this limit causes problems for a grammar in the future, it could be increased. -const TREE_SITTER_MATCH_LIMIT: u32 = 64; +/// Neovim chose 64 for this value somewhat arbitrarily (<https://github.com/neovim/neovim/pull/18397>). +/// 64 is too low for some languages though. In particular, it breaks some highlighting for record fields in Erlang record definitions. +/// This number can be increased if new syntax highlight breakages are found, as long as the performance penalty is not too high. +const TREE_SITTER_MATCH_LIMIT: u32 = 256; impl TextObjectQuery { /// Run the query on the given node and return sub nodes which match given |