Normalize some syntax table definitions

* lisp/nxml/rng-cmpct.el (rng-c-syntax-table):
* lisp/progmodes/cperl-mode.el (cperl-mode-syntax-table)
(cperl-string-syntax-table2):
* lisp/progmodes/dcl-mode.el (dcl-mode-syntax-table): Normalize
definitions to better follow modern ELisp conventions.

3 files changed, 50 insertions, 56 deletions

diff --git a/lisp/nxml/rng-cmpct.el b/lisp/nxml/rng-cmpct.el
index 453c2b736dd..85db33b9a9b 100644
--- a/lisp/nxml/rng-cmpct.el
+++ b/lisp/nxml/rng-cmpct.el
@@ -1,6 +1,6 @@
 ;;; rng-cmpct.el --- parsing of RELAX NG Compact Syntax schemas  -*- lexical-binding:t -*-
 
-;; Copyright (C) 2003, 2007-2022 Free Software Foundation, Inc.
+;; Copyright (C) 2003-2022 Free Software Foundation, Inc.
 
 ;; Author: James Clark
 ;; Keywords: wp, hypermedia, languages, XML, RelaxNG
@@ -82,19 +82,17 @@ Return a pattern."
   (concat "\\`\\(" (regexp-opt rng-c-keywords) "\\)\\'")
   "Regular expression to match a keyword in the compact syntax.")
 
-(defvar rng-c-syntax-table nil
+(defvar rng-c-syntax-table
+  (let ((st (make-syntax-table)))
+    (modify-syntax-entry ?#  "<" st)
+    (modify-syntax-entry ?\n ">" st)
+    (modify-syntax-entry ?-  "w" st)
+    (modify-syntax-entry ?.  "w" st)
+    (modify-syntax-entry ?_  "w" st)
+    (modify-syntax-entry ?:  "_" st)
+    st)
   "Syntax table for parsing the compact syntax.")
 
-(if rng-c-syntax-table
-    ()
-  (setq rng-c-syntax-table (make-syntax-table))
-  (modify-syntax-entry ?# "<" rng-c-syntax-table)
-  (modify-syntax-entry ?\n ">" rng-c-syntax-table)
-  (modify-syntax-entry ?- "w" rng-c-syntax-table)
-  (modify-syntax-entry ?. "w" rng-c-syntax-table)
-  (modify-syntax-entry ?_ "w" rng-c-syntax-table)
-  (modify-syntax-entry ?: "_" rng-c-syntax-table))
-
 (defconst rng-c-literal-1-re
   "'\\(''\\([^']\\|'[^']\\|''[^']\\)*''\\|[^'\n]*\\)'"
   "Regular expression to match a single-quoted literal.")
diff --git a/lisp/progmodes/cperl-mode.el b/lisp/progmodes/cperl-mode.el
index 539b2771490..b36896ae7ce 100644
--- a/lisp/progmodes/cperl-mode.el
+++ b/lisp/progmodes/cperl-mode.el
@@ -1429,10 +1429,40 @@ the last)."
   (rx (sequence line-start (0+ blank) (eval cperl--imenu-entries-rx)))
   "The regular expression used for `outline-minor-mode'.")
 
-(defvar cperl-mode-syntax-table nil
+(defvar cperl-mode-syntax-table
+  (let ((st (make-syntax-table)))
+    (modify-syntax-entry ?\\ "\\" st)
+    (modify-syntax-entry ?/  "."  st)
+    (modify-syntax-entry ?*  "."  st)
+    (modify-syntax-entry ?+  "."  st)
+    (modify-syntax-entry ?-  "."  st)
+    (modify-syntax-entry ?=  "."  st)
+    (modify-syntax-entry ?%  "."  st)
+    (modify-syntax-entry ?<  "."  st)
+    (modify-syntax-entry ?>  "."  st)
+    (modify-syntax-entry ?&  "."  st)
+    (modify-syntax-entry ?$  "\\" st)
+    (modify-syntax-entry ?\n ">"  st)
+    (modify-syntax-entry ?#  "<"  st)
+    (modify-syntax-entry ?'  "\"" st)
+    (modify-syntax-entry ?`  "\"" st)
+    (if cperl-under-as-char
+        (modify-syntax-entry ?_ "w" st))
+    (modify-syntax-entry ?:  "_"  st)
+    (modify-syntax-entry ?|  "."  st)
+    st)
   "Syntax table in use in CPerl mode buffers.")
 
-(defvar cperl-string-syntax-table nil
+(defvar cperl-string-syntax-table
+  (let ((st (copy-syntax-table cperl-mode-syntax-table)))
+    (modify-syntax-entry ?$  "." st)
+    (modify-syntax-entry ?\{ "." st)
+    (modify-syntax-entry ?\} "." st)
+    (modify-syntax-entry ?\" "." st)
+    (modify-syntax-entry ?'  "." st)
+    (modify-syntax-entry ?`  "." st)
+    (modify-syntax-entry ?#  "." st) ; (?# comment )
+    st)
   "Syntax table in use in CPerl mode string-like chunks.")
 
 (defsubst cperl-1- (p)
@@ -1441,38 +1471,6 @@ the last)."
 (defsubst cperl-1+ (p)
   (min (point-max) (1+ p)))
 
-(if cperl-mode-syntax-table
-    ()
-  (setq cperl-mode-syntax-table (make-syntax-table))
-  (modify-syntax-entry ?\\ "\\" cperl-mode-syntax-table)
-  (modify-syntax-entry ?/ "." cperl-mode-syntax-table)
-  (modify-syntax-entry ?* "." cperl-mode-syntax-table)
-  (modify-syntax-entry ?+ "." cperl-mode-syntax-table)
-  (modify-syntax-entry ?- "." cperl-mode-syntax-table)
-  (modify-syntax-entry ?= "." cperl-mode-syntax-table)
-  (modify-syntax-entry ?% "." cperl-mode-syntax-table)
-  (modify-syntax-entry ?< "." cperl-mode-syntax-table)
-  (modify-syntax-entry ?> "." cperl-mode-syntax-table)
-  (modify-syntax-entry ?& "." cperl-mode-syntax-table)
-  (modify-syntax-entry ?$ "\\" cperl-mode-syntax-table)
-  (modify-syntax-entry ?\n ">" cperl-mode-syntax-table)
-  (modify-syntax-entry ?# "<" cperl-mode-syntax-table)
-  (modify-syntax-entry ?' "\"" cperl-mode-syntax-table)
-  (modify-syntax-entry ?` "\"" cperl-mode-syntax-table)
-  (if cperl-under-as-char
-      (modify-syntax-entry ?_ "w" cperl-mode-syntax-table))
-  (modify-syntax-entry ?: "_" cperl-mode-syntax-table)
-  (modify-syntax-entry ?| "." cperl-mode-syntax-table)
-  (setq cperl-string-syntax-table (copy-syntax-table cperl-mode-syntax-table))
-  (modify-syntax-entry ?$ "." cperl-string-syntax-table)
-  (modify-syntax-entry ?\{ "." cperl-string-syntax-table)
-  (modify-syntax-entry ?\} "." cperl-string-syntax-table)
-  (modify-syntax-entry ?\" "." cperl-string-syntax-table)
-  (modify-syntax-entry ?' "." cperl-string-syntax-table)
-  (modify-syntax-entry ?` "." cperl-string-syntax-table)
-  (modify-syntax-entry ?# "." cperl-string-syntax-table)) ; (?# comment )
-
-
 
 (defvar cperl-faces-init nil)
 ;; Fix for msb.el
diff --git a/lisp/progmodes/dcl-mode.el b/lisp/progmodes/dcl-mode.el
index 1f363931b3c..f1d7f236b9b 100644
--- a/lisp/progmodes/dcl-mode.el
+++ b/lisp/progmodes/dcl-mode.el
@@ -258,17 +258,15 @@ See `imenu-generic-expression' for details."
 ;;; *** Global variables ****************************************************
 
 
-(defvar dcl-mode-syntax-table nil
+(defvar dcl-mode-syntax-table
+  (let ((st (make-syntax-table)))
+    (modify-syntax-entry ?!  "<" st) ; comment start
+    (modify-syntax-entry ?\n ">" st) ; comment end
+    (modify-syntax-entry ?< "(>" st) ; < and ...
+    (modify-syntax-entry ?> ")<" st) ; > is a matching pair
+    (modify-syntax-entry ?\\ "_" st) ; not an escape
+    st)
   "Syntax table used in DCL-buffers.")
-(unless dcl-mode-syntax-table
-  (setq dcl-mode-syntax-table (make-syntax-table))
-  (modify-syntax-entry ?!  "<" dcl-mode-syntax-table) ; comment start
-  (modify-syntax-entry ?\n ">" dcl-mode-syntax-table) ; comment end
-  (modify-syntax-entry ?< "(>" dcl-mode-syntax-table) ; < and ...
-  (modify-syntax-entry ?> ")<" dcl-mode-syntax-table) ; > is a matching pair
-  (modify-syntax-entry ?\\ "_" dcl-mode-syntax-table) ; not an escape
-)
-
 
 (defvar-keymap dcl-mode-map
   :doc "Keymap used in DCL-mode buffers."