Move string-trim functions to subr.el

* doc/lispref/strings.texi (Creating Strings): Document them.

* lisp/faces.el: Don't require subr-x, because that leads to build
errors.

* lisp/subr.el (string-trim, string-trim-right)
(string-trim-left): Move here from subr-x.el.

* lisp/emacs-lisp/shortdoc.el (string): Adjust.

doc/lispref/strings.texi

@@ -390,6 +390,22 @@ whitespace to a single space character, as well as removing all
 whitespace from the start and the end of @var{string}.
 @end defun
 
+@defun string-trim-left string &optional regexp
+Remove the leading text that matches @var{regexp} from @var{string}.
+@var{regexp} defaults to @samp{[ \t\n\r]+}.
+@end defun
+
+@defun string-trim-right string &optional regexp
+Remove the trailing text that matches @var{regexp} from @var{string}.
+@var{regexp} defaults to @samp{[ \t\n\r]+}.
+@end defun
+
+@defun string-trim string &optional trim-left trim-right
+Remove the leading text that matches @var{trim-left} and trailing text
+that matches @var{trim-right} from from @var{string}.  Both regexps
+default to @samp{[ \t\n\r]+}.
+@end defun
+
 @defun string-fill string length
 Attempt to Word-wrap @var{string} so that no lines are longer than
 @var{length}.  Filling is done on whitespace boundaries only.  If

lisp/emacs-lisp/shortdoc.el

@@ -168,15 +168,12 @@ There can be any number of :example/:result elements."
   (replace-regexp-in-string
    :eval (replace-regexp-in-string "[a-z]+" "_" "*foo*"))
   (string-trim
-   :no-manual t
    :args (string)
    :doc "Trim STRING of leading and trailing white space."
    :eval (string-trim " foo "))
   (string-trim-left
-   :no-manual t
    :eval (string-trim-left "oofoo" "o+"))
   (string-trim-right
-   :no-manual t
    :eval (string-trim-right "barkss" "s+"))
   (string-truncate-left
    :no-manual t

lisp/emacs-lisp/subr-x.el

@@ -215,28 +215,6 @@ The variable list SPEC is the same as in `if-let'."
 
 (define-obsolete-function-alias 'string-reverse 'reverse "25.1")
 
-(defsubst string-trim-left (string &optional regexp)
-  "Trim STRING of leading string matching REGEXP.
-
-REGEXP defaults to \"[ \\t\\n\\r]+\"."
-  (if (string-match (concat "\\`\\(?:" (or regexp "[ \t\n\r]+") "\\)") string)
-      (substring string (match-end 0))
-    string))
-
-(defsubst string-trim-right (string &optional regexp)
-  "Trim STRING of trailing string matching REGEXP.
-
-REGEXP defaults to  \"[ \\t\\n\\r]+\"."
-  (let ((i (string-match-p (concat "\\(?:" (or regexp "[ \t\n\r]+") "\\)\\'")
-                           string)))
-    (if i (substring string 0 i) string)))
-
-(defsubst string-trim (string &optional trim-left trim-right)
-  "Trim STRING of leading and trailing strings matching TRIM-LEFT and TRIM-RIGHT.
-
-TRIM-LEFT and TRIM-RIGHT default to \"[ \\t\\n\\r]+\"."
-  (string-trim-left (string-trim-right string trim-right) trim-left))
-
 ;;;###autoload
 (defun string-truncate-left (string length)
   "Truncate STRING to LENGTH, replacing initial surplus with \"...\"."

lisp/faces.el

@@ -25,8 +25,6 @@
 
 ;;; Code:
 
-(eval-when-compile (require 'subr-x))
-
 (defcustom term-file-prefix (purecopy "term/")
   "If non-nil, Emacs startup performs terminal-specific initialization.
 It does this by: (load (concat term-file-prefix (getenv \"TERM\")))

lisp/subr.el

@@ -6200,6 +6200,28 @@ returned list are in the same order as in TREE.
 ;; for discoverability:
 (defalias 'flatten-list #'flatten-tree)
 
+(defun string-trim-left (string &optional regexp)
+  "Trim STRING of leading string matching REGEXP.
+
+REGEXP defaults to \"[ \\t\\n\\r]+\"."
+  (if (string-match (concat "\\`\\(?:" (or regexp "[ \t\n\r]+") "\\)") string)
+      (substring string (match-end 0))
+    string))
+
+(defun string-trim-right (string &optional regexp)
+  "Trim STRING of trailing string matching REGEXP.
+
+REGEXP defaults to  \"[ \\t\\n\\r]+\"."
+  (let ((i (string-match-p (concat "\\(?:" (or regexp "[ \t\n\r]+") "\\)\\'")
+                           string)))
+    (if i (substring string 0 i) string)))
+
+(defun string-trim (string &optional trim-left trim-right)
+  "Trim STRING of leading and trailing strings matching TRIM-LEFT and TRIM-RIGHT.
+
+TRIM-LEFT and TRIM-RIGHT default to \"[ \\t\\n\\r]+\"."
+  (string-trim-left (string-trim-right string trim-right) trim-left))
+
 ;; The initial anchoring is for better performance in searching matches.
 (defconst regexp-unmatchable "\\`a\\`"
   "Standard regexp guaranteed not to match any string at all.")