Add a depth argument.

scripts/lib/bashy-core/stderr-messages.sh

@@ -17,8 +17,9 @@
 #   when "manually" turning on or off messages.
 # --exec -- Execute the arguments as a command, instead of treating them as
 #   arguments to print. The command's output gets redirected to `stderr`.
-# --file-line -- Include the caller-of-the-caller's file and line number. That
-#   is, a user of the command can use this to talk about what called it.
+# --file-line=<depth> -- Include the caller's file and line number, at the
+#   indicated stack depth up from the caller, with `0` being the caller. That
+#   is, a user of the command can use this to refer to what called it.
 # --set=0|1 -- Enable or disable printing of this kind of message.
 # --status -- Prints `1` or `0` to stdout, to indicate enabled status. (This is
 #   to make it easy to propagate the enabled state down into another command.)
@@ -106,7 +107,7 @@ function _stderr_print-handler {
     shift 2
 
     local doExec=0
-    local doFileLine=0
+    local fileLineDepth=-1
     local printName=1
     local wasCmd=0
 
@@ -123,8 +124,8 @@ function _stderr_print-handler {
             --exec)
                 doExec=1
                 ;;
-            --file-line)
-                doFileLine=1
+            --file-line=*)
+                fileLineDepth="${1#*=}"
                 ;;
             --no-name)
                 if [[ ${anyMessagesVarName} == '' ]]; then
@@ -162,12 +163,12 @@ function _stderr_print-handler {
         eval "${anyMessagesVarName}=1"
     fi
 
-    if (( doFileLine )); then
+    if (( fileLineDepth >= 0 )); then
         if (( didPrintName )); then
             printf 1>&2 '\n'
         fi
-        # `3` (and not `2`) because there's an internal caller layer to elide.
-        [[ "$(caller 3)" =~ ^([0-9]+).*/(.*)$ ]]
+        # `+ 1` because there's an internal caller layer to elide.
+        [[ "$(caller "$((fileLineDepth + 1))")" =~ ^([0-9]+).*/(.*)$ ]]
         printf 1>&2 '%s:%s: ' "${BASH_REMATCH[2]}" "${BASH_REMATCH[1]}"
     fi