diff --git a/src/Makefile.am b/src/Makefile.am
index c18adac2d..c341d4050 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -248,6 +248,7 @@ harfbuzz-deprecated-symbols.txt: $(srcdir)/hb-deprecated.h
 
 
 GENERATORS = \
+	gen-arabic-joining-list.py \
 	gen-arabic-table.py \
 	gen-def.py \
 	gen-emoji-table.py \
diff --git a/src/Makefile.sources b/src/Makefile.sources
index 4ad11e2bc..8bb291206 100644
--- a/src/Makefile.sources
+++ b/src/Makefile.sources
@@ -105,6 +105,7 @@ HB_BASE_sources = \
 	hb-ot-post-macroman.hh \
 	hb-ot-post-table.hh \
 	hb-ot-shape-complex-arabic-fallback.hh \
+	hb-ot-shape-complex-arabic-joining-list.hh \
 	hb-ot-shape-complex-arabic-table.hh \
 	hb-ot-shape-complex-arabic-win1256.hh \
 	hb-ot-shape-complex-arabic.cc \
diff --git a/src/gen-arabic-joining-list.py b/src/gen-arabic-joining-list.py
new file mode 100755
index 000000000..78c44c35d
--- /dev/null
+++ b/src/gen-arabic-joining-list.py
@@ -0,0 +1,104 @@
+#!/usr/bin/env python3
+
+"""usage: ./gen-arabic-joining-table.py ArabicShaping.txt Scripts.txt
+
+Input files:
+* https://unicode.org/Public/UCD/latest/ucd/ArabicShaping.txt
+* https://unicode.org/Public/UCD/latest/ucd/Scripts.txt
+"""
+
+import os.path, sys
+
+if len (sys.argv) != 3:
+	sys.exit (__doc__)
+
+files = [open (x, encoding='utf-8') for x in sys.argv[1:]]
+
+headers = [[f.readline (), f.readline ()] for f in files]
+while files[0].readline ().find ('##################') < 0:
+	pass
+
+def read (f):
+	mapping = {}
+	for line in f:
+
+		j = line.find ('#')
+		if j >= 0:
+			line = line[:j]
+
+		fields = [x.strip () for x in line.split (';')]
+		if len (fields) == 1:
+			continue
+
+		uu = fields[0].split ('..')
+		start = int (uu[0], 16)
+		if len (uu) == 1:
+			end = start
+		else:
+			end = int (uu[1], 16)
+
+		t = fields[1]
+
+		for u in range (start, end + 1):
+			mapping[u] = t
+
+	return mapping
+
+def read_joining_uu (f):
+	values = set ()
+	for line in f:
+
+		if line[0] == '#':
+			continue
+
+		fields = [x.strip () for x in line.split (';')]
+		if len (fields) == 1:
+			continue
+
+		values.add (int (fields[0], 16))
+
+	return sorted (values)
+
+def print_has_arabic_joining (scripts, joining_uu):
+
+	print ("static bool")
+	print ("has_arabic_joining (hb_script_t script)")
+	print ("{")
+	print ("  /* List of scripts that have data in arabic-table. */")
+	print ("  switch ((int) script)")
+	print ("  {")
+
+	for script in sorted ({scripts[u] for u in joining_uu if scripts[u] not in {'Common', 'Inherited'}}):
+		print ("    case HB_SCRIPT_{}:".format (script.upper ()))
+
+	print ("      return true;")
+	print ()
+	print ("    default:")
+	print ("      return false;")
+	print ("  }")
+	print ("}")
+	print ()
+
+print ("/* == Start of generated function == */")
+print ("/*")
+print (" * The following function is generated by running:")
+print (" *")
+print (" *   ./gen-arabic-joining-list.py ArabicShaping.txt Scripts.txt")
+print (" *")
+print (" * on files with these headers:")
+print (" *")
+for h in headers:
+	for l in h:
+		print (" * %s" % (l.strip ()))
+print (" */")
+print ()
+print ("#ifndef HB_OT_SHAPE_COMPLEX_ARABIC_JOINING_LIST_HH")
+print ("#define HB_OT_SHAPE_COMPLEX_ARABIC_JOINING_LIST_HH")
+print ()
+
+print_has_arabic_joining (read (files[1]), read_joining_uu (files[0]))
+
+print ()
+print ("#endif /* HB_OT_SHAPE_COMPLEX_ARABIC_JOINING_LIST_HH */")
+print ()
+print ("/* == End of generated function == */")
diff --git a/src/hb-ot-shape-complex-arabic-joining-list.hh b/src/hb-ot-shape-complex-arabic-joining-list.hh
new file mode 100644
index 000000000..140310333
--- /dev/null
+++ b/src/hb-ot-shape-complex-arabic-joining-list.hh
@@ -0,0 +1,47 @@
+/* == Start of generated function == */
+/*
+ * The following function is generated by running:
+ *
+ *   ./gen-arabic-joining-list.py ArabicShaping.txt Scripts.txt
+ *
+ * on files with these headers:
+ *
+ * # ArabicShaping-13.0.0.txt
+ * # Date: 2020-01-31, 23:55:00 GMT [KW, RP]
+ * # Scripts-13.0.0.txt
+ * # Date: 2020-01-22, 00:07:43 GMT
+ */
+
+#ifndef HB_OT_SHAPE_COMPLEX_ARABIC_JOINING_LIST_HH
+#define HB_OT_SHAPE_COMPLEX_ARABIC_JOINING_LIST_HH
+
+static bool
+has_arabic_joining (hb_script_t script)
+{
+  /* List of scripts that have data in arabic-table. */
+  switch ((int) script)
+  {
+    case HB_SCRIPT_ADLAM:
+    case HB_SCRIPT_ARABIC:
+    case HB_SCRIPT_CHORASMIAN:
+    case HB_SCRIPT_HANIFI_ROHINGYA:
+    case HB_SCRIPT_KAITHI:
+    case HB_SCRIPT_MANDAIC:
+    case HB_SCRIPT_MANICHAEAN:
+    case HB_SCRIPT_MONGOLIAN:
+    case HB_SCRIPT_NKO:
+    case HB_SCRIPT_PHAGS_PA:
+    case HB_SCRIPT_PSALTER_PAHLAVI:
+    case HB_SCRIPT_SOGDIAN:
+    case HB_SCRIPT_SYRIAC:
+      return true;
+
+    default:
+      return false;
+  }
+}
+
+
+#endif /* HB_OT_SHAPE_COMPLEX_ARABIC_JOINING_LIST_HH */
+
+/* == End of generated function == */
diff --git a/src/hb-ot-shape-complex-use.cc b/src/hb-ot-shape-complex-use.cc
index 10f5822c0..981df2d59 100644
--- a/src/hb-ot-shape-complex-use.cc
+++ b/src/hb-ot-shape-complex-use.cc
@@ -32,6 +32,7 @@
 
 #include "hb-ot-shape-complex-use.hh"
 #include "hb-ot-shape-complex-arabic.hh"
+#include "hb-ot-shape-complex-arabic-joining-list.hh"
 #include "hb-ot-shape-complex-vowel-constraints.hh"
 
 /* buffer var allocations */
@@ -152,40 +153,6 @@ struct use_shape_plan_t
   arabic_shape_plan_t *arabic_plan;
 };
 
-static bool
-has_arabic_joining (hb_script_t script)
-{
-  /* List of scripts that have data in arabic-table. */
-  switch ((int) script)
-  {
-    /* Unicode-1.1 additions */
-    case HB_SCRIPT_ARABIC:
-
-    /* Unicode-3.0 additions */
-    case HB_SCRIPT_MONGOLIAN:
-    case HB_SCRIPT_SYRIAC:
-
-    /* Unicode-5.0 additions */
-    case HB_SCRIPT_NKO:
-    case HB_SCRIPT_PHAGS_PA:
-
-    /* Unicode-6.0 additions */
-    case HB_SCRIPT_MANDAIC:
-
-    /* Unicode-7.0 additions */
-    case HB_SCRIPT_MANICHAEAN:
-    case HB_SCRIPT_PSALTER_PAHLAVI:
-
-    /* Unicode-9.0 additions */
-    case HB_SCRIPT_ADLAM:
-
-      return true;
-
-    default:
-      return false;
-  }
-}
-
 static void *
 data_create_use (const hb_ot_shape_plan_t *plan)
 {
diff --git a/src/meson.build b/src/meson.build
index 853e0eb10..a4abfb726 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -104,6 +104,7 @@ hb_base_sources = files(
   'hb-ot-post-macroman.hh',
   'hb-ot-post-table.hh',
   'hb-ot-shape-complex-arabic-fallback.hh',
+  'hb-ot-shape-complex-arabic-joining-list.hh',
   'hb-ot-shape-complex-arabic-table.hh',
   'hb-ot-shape-complex-arabic-win1256.hh',
   'hb-ot-shape-complex-arabic.cc',
diff --git a/src/update-unicode-tables.make b/src/update-unicode-tables.make
index c2d879a39..93b1ccaab 100755
--- a/src/update-unicode-tables.make
+++ b/src/update-unicode-tables.make
@@ -1,6 +1,7 @@
 #!/usr/bin/env -S make -f
 
 all: packtab \
+	hb-ot-shape-complex-arabic-joining-list.hh \
 	hb-ot-shape-complex-arabic-table.hh hb-unicode-emoji-table.hh \
 	hb-ot-shape-complex-indic-table.cc hb-ot-tag-table.hh \
 	hb-ucd-table.hh hb-ot-shape-complex-use-table.cc \
@@ -8,6 +9,8 @@ all: packtab \
 
 .PHONY: all clean packtab
 
+hb-ot-shape-complex-arabic-joining-list.hh: gen-arabic-joining-list.py ArabicShaping.txt Scripts.txt
+	./$^ > $@ || ($(RM) $@; false)
 hb-ot-shape-complex-arabic-table.hh: gen-arabic-table.py ArabicShaping.txt UnicodeData.txt Blocks.txt
 	./$^ > $@ || ($(RM) $@; false)
 hb-unicode-emoji-table.hh: gen-emoji-table.py emoji-data.txt