diff --git a/NEWS.md b/NEWS.md
index f959491d..bbc8f7af 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -15,6 +15,7 @@
     * The `meta` directive is now supported: `{meta: COMMANDNAME:arg}` [#220](https://github.com/patacrep/patacrep/pull/220)
   * LaTeX songs
     * The `meta` directive is now supported: `\metacrep{COMMANDNAME}{arg}` [#220](https://github.com/patacrep/patacrep/pull/220)
+  * Faster index generation [#233](https://github.com/patacrep/patacrep/pull/233)
 
 # patacrep 5.0.0
 
diff --git a/patacrep/latex/syntax.py b/patacrep/latex/syntax.py
index edf9ceb1..b6daefd0 100644
--- a/patacrep/latex/syntax.py
+++ b/patacrep/latex/syntax.py
@@ -1,6 +1,7 @@
 """Very simple LaTeX parser"""
 
 import logging
+from functools import lru_cache
 import ply.yacc as yacc
 
 from patacrep.latex import ast
@@ -211,15 +212,20 @@ def silent_yacc(*args, **kwargs):
         **kwargs
         )
 
+@lru_cache()
+def latex_yacc(filename=None):
+    """Call the yacc with the LaTeX parser.
+    """
+    parser = silent_yacc(module=LatexParser(filename))
+    return parser
+
 def tex2plain(string):
     """Parse string and return its plain text version."""
     return detex(
-        silent_yacc(
-            module=LatexParser(),
-            ).parse(
-                string,
-                lexer=SimpleLexer().lexer,
-                )
+        latex_yacc().parse(
+            string,
+            lexer=SimpleLexer().lexer,
+            )
         )
 
 def parse_song(content, filename=None):
@@ -231,7 +237,7 @@ def parse_song(content, filename=None):
       display error messages.
     """
     return detex(
-        silent_yacc(module=LatexParser(filename)).parse(
+        latex_yacc(filename).parse(
             content,
             lexer=SongLexer().lexer,
             ).metadata