Re: [PATCH] Allow user-defined functions to override builtins.

[Ben Hildred]

On Mon, May 19, 2014 at 3:38 AM, Michel Hermier <address@hidden> wrote:

Le 19/05/2014 08:37, Glenn Washburn a écrit :

Currently, builtin commands take precedence over user-defined
functions.  This patch reverses that precedence, so that users can
"override" builtin commands.  Builtin commands may be accessed by
issuing the command prefixed by an '@' character.

If you want to go this way, I would have preferred a 'builtin' command like other shell do, instead of reinventing the wheel and invent a new syntax.
But this only my opinion as a user, wait for developers opinion.

Seconded, particularly  as the @ syntax is used elsewhere as echo suppression. there is no need to confuse people.

My motivation for this change is to hook insmod in loaded configfiles
which set $prefix to a different location than desired.  If there are
any changes needed to help get this functionality included, please let
me know.

Glenn

---
  grub-core/script/execute.c | 17 +++++++++--------
  1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/grub-core/script/execute.c b/grub-core/script/execute.c
index afd5513..0769151 100644
--- a/grub-core/script/execute.c
+++ b/grub-core/script/execute.c
@@ -941,14 +941,15 @@ grub_script_execute_cmdline (struct
grub_script_cmd *cmd) args = argv.args + 2;
        cmdname = argv.args[1];
      }
-  grubcmd = grub_command_find (cmdname);
-  if (! grubcmd)
+  /* Allow user functions to override built in commands. */
+  func = grub_script_function_find (cmdname);
+  if (! func)
      {
        grub_errno = GRUB_ERR_NONE;
  -      /* It's not a GRUB command, try all functions.  */
-      func = grub_script_function_find (cmdname);
-      if (! func)
+      /* It's not a function, check if GRUB command.  */
+      grubcmd = grub_command_find ((cmdname[0] ==
'@')?(cmdname+1):cmdname);
+      if (! grubcmd)
        {
          /* As a last resort, try if it is an assignment.  */
          char *assign = grub_strdup (cmdname);
@@ -977,7 +978,9 @@ grub_script_execute_cmdline (struct grub_script_cmd
*cmd) }
      /* Execute the GRUB command or function.  */
-  if (grubcmd)
+  if (func)
+    ret = grub_script_function_call (func, argc, args);
+  else
      {
        if (grub_extractor_level && !(grubcmd->flags
                                    & GRUB_COMMAND_FLAG_EXTRACTOR))
@@ -990,8 +993,6 @@ grub_script_execute_cmdline (struct grub_script_cmd
*cmd) else
        ret = (grubcmd->func) (grubcmd, argc, args);
      }
-  else
-    ret = grub_script_function_call (func, argc, args);
      if (invert)
      {

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Ben Hildred

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