48606 + 48607 + unposted test: zmathfunc: Force arguments to be numbers and catch errors.

ChangeLog

@@ -1,5 +1,9 @@
 2021-04-21  Daniel Shahaf  <d.s@daniel.shahaf.name>
 
+	* 48606 + 48607 + unposted test: Functions/Math/zmathfunc,
+	Test/Z02zmathfunc.ztst: zmathfunc: Force arguments to be numbers
+	and catch errors.
+
 	* unposted (cf. 48156): Test/Z02zmathfunc.ztst: New test.
 
 	* users/26635 (tweaked):

Functions/Math/zmathfunc

@@ -6,7 +6,12 @@ zsh_math_func_min() {
   shift
   local arg
   for arg ; do
-    (( $arg < result )) && result=$arg
+    (( arg < result ))
+    case $? in
+      (0) (( result = arg ));;
+      (1) ;;
+      (*) return $?;;
+    esac
   done
   (( result ))
   true # Careful here: `return 0` evaluates an arithmetic expression
@@ -19,7 +24,12 @@ zsh_math_func_max() {
   shift
   local arg
   for arg ; do
-    (( $arg > result )) && result=$arg
+    (( arg > result ))
+    case $? in
+      (0) (( result = arg ));;
+      (1) ;;
+      (*) return $?;;
+    esac
   done
   (( result ))
   true # Careful here: `return 0` evaluates an arithmetic expression
@@ -31,7 +41,7 @@ zsh_math_func_sum() {
   local sum
   local arg
   for arg ; do
-    (( sum += $arg ))
+    (( sum += arg ))
   done
   (( sum ))
   true # Careful here: `return 0` evaluates an arithmetic expression

Test/Z02zmathfunc.ztst

@@ -44,7 +44,13 @@
 ?(eval):1: wrong number of arguments: max()
 
  zsh_math_func_min "foo bar" x y z
-2dDf:check errors from an unsupported use-case (workers/48156)
+2d:check errors from an unsupported use-case (workers/48156)
+# We expect one non-empty line of stderr, but don't care about the specific
+# error message; thus, the expectation is a pattern (*), for stderr (?), which
+# matches any non-empty string (?*).
+#
+# Sorry, Perl, but I had to give you a run for your money.
+*??*
 F:Calling zsh_math_func_min directly isn't a supported use-case, but if it
 F:returns zero, something's probably wrong.