2 files changed, 40 insertions, 0 deletions
diff --git a/pkgs/applications/science/chemistry/openmolcas/default.nix b/pkgs/applications/science/chemistry/openmolcas/default.nix
index 33c77c063bf91..0aeb01c2916b5 100644
--- a/pkgs/applications/science/chemistry/openmolcas/default.nix
+++ b/pkgs/applications/science/chemistry/openmolcas/default.nix
@@ -59,6 +59,9 @@ stdenv.mkDerivation {
 
     # Required for a local QCMaquis build
     ./qcmaquis.patch
+
+    # PyParsing >= 3.11 compatibility, can be removed on next release
+    ./pyparsing.patch
   ];
 
   postPatch = ''
diff --git a/pkgs/applications/science/chemistry/openmolcas/pyparsing.patch b/pkgs/applications/science/chemistry/openmolcas/pyparsing.patch
new file mode 100644
index 0000000000000..271b52840ff93
--- /dev/null
+++ b/pkgs/applications/science/chemistry/openmolcas/pyparsing.patch
@@ -0,0 +1,37 @@
+diff --git a/Tools/pymolcas/emil_grammar.py b/Tools/pymolcas/emil_grammar.py
+index acbbae8..509c56f 100644
+--- a/Tools/pymolcas/emil_grammar.py
++++ b/Tools/pymolcas/emil_grammar.py
+@@ -15,6 +15,14 @@
+ 
+ from __future__ import (unicode_literals, division, absolute_import, print_function)
+ 
++try:
++  u = unicode
++  del u
++  py2 = True
++except NameError:
++  pass
++
++
+ from re import sub
+ from pyparsing import *
+ 
+@@ -24,6 +32,8 @@ def chomp(s):
+ 
+ def chompAction(s, l, t):
+   try:
++    if (py2):
++      pass
+     return list(map(lambda s: chomp(unicode(s)), t))
+   except NameError:
+     return list(map(chomp, t))
+@@ -33,6 +43,8 @@ def removeEMILEnd(s):
+ 
+ def removeEMILEndAction(s, l, t):
+   try:
++    if (py2):
++      pass
+     return list(map(lambda s: removeEMILEnd(unicode(s)), t))
+   except NameError:
+     return list(map(removeEMILEnd, t))