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Hu Tao

2014-Nov-28 09:55 UTC

[Libguestfs] [PATCH] fish: show synopsis if command syntax is wrong

This patch lets guestfish show command synopsis if the syntax of command issued
by user is wrong, rather than telling user that the number of parameters is
wrong.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
---
 fish/cmds-gperf.h |  1 +
 generator/fish.ml | 33 ++++++++++++---------------------
 2 files changed, 13 insertions(+), 21 deletions(-)

diff --git a/fish/cmds-gperf.h b/fish/cmds-gperf.h
index 74db69d..bcb3b5d 100644
--- a/fish/cmds-gperf.h
+++ b/fish/cmds-gperf.h
@@ -25,6 +25,7 @@
 struct command_entry {
   const char *name;             /* Short name. */
   const char *help;             /* Online help. */
+  const char *synopsis;         /* Synopsis. */
 
   /* The run_* function. */
   int (*run) (const char *cmd, size_t argc, char *argv[]);
diff --git a/generator/fish.ml b/generator/fish.ml
index 3f53ffa..951b376 100644
--- a/generator/fish.ml
+++ b/generator/fish.ml
@@ -190,6 +190,7 @@ Guestfish will prompt for these separately."
       pr "struct command_entry %s_cmd_entry = {\n" name;
       pr "  .name = \"%s\",\n" name2;
       pr "  .help = \"%s\",\n" (c_quote text);
+      pr "  .synopsis = \"%s\",\n" (c_quote synopsis);
       pr "  .run = run_%s\n" name;
       pr "};\n";
       pr "\n";
@@ -393,30 +394,14 @@ Guestfish will prompt for these separately."
 
       if argc_minimum = argc_maximum then (
         pr "  if (argc != %d) {\n" argc_minimum;
-        if argc_minimum = 0 then (
-          pr "    fprintf (stderr, _(\"%%s should have no
parameters\\n\"), cmd);\n";
-        ) else (
-          pr "    fprintf (stderr, ngettext(\"%%s should have %%d
parameter\\n\",\n";
-          pr "                              \"%%s should have %%d
parameters\\n\",\n";
-          pr "                              %d),\n"
-            argc_minimum;
-          pr "                     cmd, %d);\n"
-            argc_minimum;
-        )
+          pr "    ret = -2;\n";
       ) else if argc_minimum = 0 then (
         pr "  if (argc > %d) {\n" argc_maximum;
-        pr "    fprintf (stderr, ngettext(\"%%s should have at most
%%d parameter\\n\",\n";
-        pr "                              \"%%s should have at most
%%d parameters\\n\",\n";
-        pr "                              %d),\n"
-          argc_maximum;
-        pr "                     cmd, %d);\n"
-          argc_maximum;
+        pr "    ret = -2;\n";
       ) else (
         pr "  if (argc < %d || argc > %d) {\n" argc_minimum
argc_maximum;
-        pr "    fprintf (stderr, _(\"%%s should have %%d-%%d
parameter(s)\\n\"), cmd, %d, %d);\n"
-          argc_minimum argc_maximum;
+        pr "    ret = -2;\n";
       );
-      pr "    fprintf (stderr, _(\"type 'help %%s' for help
on %%s\\n\"), cmd, cmd);\n";
       pr "    goto out_noargs;\n";
       pr "  }\n";
 
@@ -694,10 +679,16 @@ Guestfish will prompt for these separately."
   pr "run_action (const char *cmd, size_t argc, char *argv[])\n";
   pr "{\n";
   pr "  const struct command_table *ct;\n";
+  pr "  int ret = -1;\n";
   pr "\n";
   pr "  ct = lookup_fish_command (cmd, strlen (cmd));\n";
-  pr "  if (ct)\n";
-  pr "    return ct->entry->run (cmd, argc, argv);\n";
+  pr "  if (ct) {\n";
+  pr "    ret = ct->entry->run (cmd, argc, argv);\n";
+  pr "    if (ret == -2) {\n";
+  pr "      fprintf (stderr, _(\"usage: %%s\\n\"),
ct->entry->synopsis);\n";
+  pr "      fprintf (stderr, _(\"type 'help %%s' for more
help on %%s\\n\"), cmd, cmd);\n";
+  pr "    }\n";
+  pr "  }\n";
   pr "  else {\n";
   pr "    fprintf (stderr, _(\"%%s: unknown command\\n\"),
cmd);\n";
   pr "    if (command_num == 1)\n";
-- 
1.9.3

Pino Toscano

2014-Nov-28 14:00 UTC

head link

Re: [Libguestfs] [PATCH] fish: show synopsis if command syntax is wrong

On Friday 28 November 2014 17:55:51 Hu Tao wrote:> This patch lets guestfish show command synopsis if the syntax of command
issued
> by user is wrong, rather than telling user that the number of parameters is
wrong.
The idea seems sound to me.

Shouldn't that be done also for fish commands? If so, just make
"synopsis" a function taking args and optargs, and use it in both
places.
> @@ -694,10 +679,16 @@ Guestfish will prompt for these separately."
>    pr "run_action (const char *cmd, size_t argc, char
*argv[])\n";
>    pr "{\n";
>    pr "  const struct command_table *ct;\n";
> +  pr "  int ret = -1;\n";
>    pr "\n";
>    pr "  ct = lookup_fish_command (cmd, strlen (cmd));\n";
> -  pr "  if (ct)\n";
> -  pr "    return ct->entry->run (cmd, argc, argv);\n";
> +  pr "  if (ct) {\n";
> +  pr "    ret = ct->entry->run (cmd, argc, argv);\n";
> +  pr "    if (ret == -2) {\n";
> +  pr "      fprintf (stderr, _(\"usage: %%s\\n\"),
ct->entry->synopsis);\n";
> +  pr "      fprintf (stderr, _(\"type 'help %%s' for
more help on %%s\\n\"), cmd, cmd);\n";
> +  pr "    }\n";
> +  pr "  }\n";
There is an issue here: in the true branch of "if (ct)", there is no
more return, and thus builds fails when enabling -Werror
(--enable-werror for configure):

cmds.c: In function 'run_action':
cmds.c:23233:1: error: control reaches end of non-void function
[-Werror=return-type]
 }
 ^

Also, the return code -2 must be turned as -1.

-- 
Pino Toscano

Hu Tao

2014-Dec-01 02:25 UTC

head link

Re: [Libguestfs] [PATCH] fish: show synopsis if command syntax is wrong

On Fri, Nov 28, 2014 at 03:00:39PM +0100, Pino Toscano
wrote:> On Friday 28 November 2014 17:55:51 Hu Tao wrote:
> > This patch lets guestfish show command synopsis if the syntax of
command issued
> > by user is wrong, rather than telling user that the number of
parameters is wrong.
> 
> The idea seems sound to me.
> 
> Shouldn't that be done also for fish commands? If so, just make
> "synopsis" a function taking args and optargs, and use it in both
> places.
fish commands do not have args and optargs in their definitions in file
actions.ml. Also, fish commands' synopsises are printed out by inline
codes, see run_alloc() for an example.

Surely we can reconstruct fish commands' definitions to take advantage
of the auto-generation of synopsis done in this patch, but that can be
another patch. I'll add this to my todo list.
> 
> > @@ -694,10 +679,16 @@ Guestfish will prompt for these
separately."
> >    pr "run_action (const char *cmd, size_t argc, char
*argv[])\n";
> >    pr "{\n";
> >    pr "  const struct command_table *ct;\n";
> > +  pr "  int ret = -1;\n";
> >    pr "\n";
> >    pr "  ct = lookup_fish_command (cmd, strlen (cmd));\n";
> > -  pr "  if (ct)\n";
> > -  pr "    return ct->entry->run (cmd, argc,
argv);\n";
> > +  pr "  if (ct) {\n";
> > +  pr "    ret = ct->entry->run (cmd, argc, argv);\n";
> > +  pr "    if (ret == -2) {\n";
> > +  pr "      fprintf (stderr, _(\"usage: %%s\\n\"),
ct->entry->synopsis);\n";
> > +  pr "      fprintf (stderr, _(\"type 'help %%s'
for more help on %%s\\n\"), cmd, cmd);\n";
> > +  pr "    }\n";
> > +  pr "  }\n";
> 
> There is an issue here: in the true branch of "if (ct)", there is
no
> more return, and thus builds fails when enabling -Werror
> (--enable-werror for configure):
> 
> cmds.c: In function 'run_action':
> cmds.c:23233:1: error: control reaches end of non-void function
[-Werror=return-type]
>  }
>  ^
> 
> Also, the return code -2 must be turned as -1.
Thanks, both fixed.

Regards,
Hu
> 
> -- 
> Pino Toscano
> 
> _______________________________________________
> Libguestfs mailing list
> Libguestfs@redhat.com
> https://www.redhat.com/mailman/listinfo/libguestfs

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