Attempt caching of lexed lines to speed things up

1 files changed, 10 insertions, 1 deletions

diff --git a/lib/lace/lex.lua b/lib/lace/lex.lua
index 1085bed..af891af 100644
--- a/lib/lace/lex.lua
+++ b/lib/lace/lex.lua
@@ -15,7 +15,7 @@
 
 local M = {}
 
-local function lex_one_line(line)
+local function _lex_one_line(line)
    local r = {}
    local acc = ""
    local c
@@ -91,6 +91,15 @@ local function lex_one_line(line)
    return r, warnings
 end
 
+local lexer_line_cache = {}
+
+local function lex_one_line(line)
+   if not lexer_line_cache[line] then
+      lexer_line_cache[line] = { _lex_one_line(line) }
+   end
+   return lexer_line_cache[line][1], lexer_line_cache[line][2]
+end
+
 --- Lexically analyse a ruleset.
 -- @tparam string ruleset The ruleset to lex.
 -- @tparam string sourcename The name of the source to go into debug info.