Add an S-OR macro.

See #132

Author: tdrhq

README.md

@@ -90,6 +90,7 @@ The only dependency is `cl-ppcre`.
     - [Macros](#macros)
         - [string-case](#string-case)
         - [match (experimental) · new in Feb, 2024](#match-experimental--new-in-feb-2024)
+        - [s-or](#s-or)
     - [Changelog](#changelog)
     - [Dev and test](#dev-and-test)
         - [Main test suite](#main-test-suite)
@@ -961,6 +962,21 @@ Match with regexs:
 ;; => " hello "
 ```
 
+### s-or
+
+Similar to OR, but finds the first argument that is not `(STR:EMPTYP)`. 
+
+```lisp
+(str:s-or "" "foo") 
+;; => "foo"
+
+(str:s-or nil "foo")
+;; => "foo"
+
+(str:s-or "foo" (error "will not be evaluated"))
+;; => "foo"
+```
+
 ## Changelog
 
 * September, 2025:

str.lisp

@@ -38,6 +38,7 @@
   #:suffixp
   #:add-prefix
   #:add-suffix
+  #:s-or
 
   #:ensure
   #:ensure-prefix
@@ -1306,6 +1307,19 @@ unless MERGE-NUMBERS is non-nil.
         ""
         (replace-non-word s))))
 
+(defmacro s-or (&rest args)
+  "Similar to CL:OR, but returns the first non-empty string. If all the
+strings are empty or NIL, then we return NIL.
+
+Like OR, expressions are evaluated from left to right, until the first
+expression returns a non-empty string."
+  (let ((var (gensym)))
+   `(or
+     ,@ (loop for arg in args
+              collect `(let ((var ,arg))
+                         (unless (str:emptyp var)
+                           var))))))
+
 ;; "deprecated" function alias
 (setf (fdefinition 'prune)        #'shorten
       (fdefinition 'common-prefix) #'prefix

test/test-str.lisp

@@ -793,3 +793,20 @@ def"))
                   s)
                  (t "nothing")))
       "match with the regex"))
+
+(test s-or
+  (is (equal
+       "foo"
+       (str:s-or nil "foo" "bar")))
+  (is (equal
+       "foo"
+       (str:s-or "" "foo" "bar")))
+  (is (equal
+       nil
+       (str:s-or)))
+  (is (equal
+       nil
+       (str:s-or "" "")))
+  (is (equal
+       "foo"
+       (str:s-or "foo" (error "will not be evaluated")))))