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( See original discussion and prototype here: https://sourceware.org/ml/gdb-patches/2019-05/msg00570.html ) (gdb) help with Temporarily set SETTING to VALUE, run COMMAND, and restore SETTING. Usage: with SETTING [VALUE] [-- COMMAND] Usage: w SETTING [VALUE] [-- COMMAND] With no COMMAND, repeats the last executed command. SETTING is any setting you can change with the "set" subcommands. E.g.: with language pascal -- print obj with print elements unlimited -- print obj As can be seen above, the "with" command is just like "set", but instead of setting the setting permanently, it sets the setting, runs a command and then restores the setting. (gdb) p g_s $1 = {a = 1, b = 2, c = 3} (gdb) with language ada -- print g_s $2 = (a => 1, b => 2, c => 3) Warning: the current language does not match this frame. (gdb) show language The current source language is "auto; currently c". (gdb) with print elements 100 -- with print object on -- print 1 $3 = 1 You can shorten things a bit though, as long as unambiguous. So this: (gdb) with print elements 100 -- with print object off -- print 1 is the same as: (gdb) w p el 100 -- w p o 0 -- p 1 Note that the patch adds a "w" alias for "with", as "w" is not currently taken: (gdb) w Ambiguous command "w": watch, wh, whatis, where, while, while-stepping, winheight, ws. Let me know if you'd prefer to reserve "w" for one of the other commands above. IMHO, this command will end up being used frequently enough that it deserves the "w" shorthand. A nice feature is that this is fully integrated with TAB-completion: (gdb) with p[TAB] pagination print prompt python (gdb) with print [TAB] address max-depth static-members array max-symbolic-offset symbol array-indexes null-stop symbol-filename asm-demangle object symbol-loading demangle pascal_static-members thread-events elements pretty type entry-values raw union frame-arguments repeats vtbl inferior-events sevenbit-strings (gdb) with print [TAB] (gdb) with print elements unlimited -- thread apply all -[TAB] -ascending -c -q -s (gdb) with print elements unlimited -- print -[TAB] -address -max-depth -repeats -vtbl -array -null-stop -static-members -array-indexes -object -symbol -elements -pretty -union The main advantage of this new command compared to command options, like the new "print -OPT", is that this command works with any setting, and, it works nicely when you want to override a setting while running a user-defined command, like: (gdb) with print pretty -- usercmd The disadvantage is that it isn't as compact or easy to type. I think of command options and this command as complementary. I think that even with this new command, it makes sense to continue developing the command options in the direction of exposing most-oft-used settings as command options. Inspired by Philippe's "/" command proposal, if no command is specified, then the last command is re-invoked, under the overridden setting: (gdb) p g_s $1 = {a = 1, b = 2, c = 3} (gdb) with language ada $2 = (a => 1, b => 2, c => 3) Warning: the current language does not match this frame. Note: "with" requires "--" to separate the setting from the command. It might be possible to do without that, but, I haven't tried it yet, and I think that this can go in without it. We can always downgrade to making "--" optional if we manage to make it work. On to the patch itself, the implementation of the command is simpler than one might expect. A few details: - I factored out a bit from pipe_command into repeat_previous directly, because otherwise I'd need to copy&paste the same code and same error message in the with command. - The parse_cli_var_uinteger / parse_cli_var_zuinteger_unlimited / do_set_command changes are necessary since we can now pass an empty string as argument. - do_show_command was split in two, as a FIXME comment suggests, but for a different reason: we need to get a string version of a "set" command's value, and we already had code for that in do_show_command. That code is now factored out to the new get_setshow_command_value_string function. - There's a new "maint with" command added too: (gdb) help maint with Like "with", but works with "maintenance set" variables. Usage: maintenance with SETTING [VALUE] [-- COMMAND] With no COMMAND, repeats the last executed command. SETTING is any setting you can change with the "maintenance set" subcommands. "with" and "maint with" share 99% of the implementation. This might be useful on its own, but it's also useful for testing, since with this, we can use the "maint set/show test-settings" settings for exercising the "with" machinery with all the command type variants (all enum var_types). This is done in the new gdb/base/with.exp testcase. The documentation bits are originally based on Philippe's docs for the "/" command, hence the attribution in the ChangeLog. gdb/ChangeLog: 2019-07-03 Pedro Alves <palves@redhat.com> * NEWS (New commands): Mention "with" and "maint with". * cli/cli-cmds.c (with_command_1, with_command_completer_1) (with_command, with_command_completer): New. (pipe_command): Adjust to new repeat_previous interface. (_initialize_cli_cmds): Install the "with" command and its "w" alias. * cli/cli-cmds.h (with_command_1, with_command_completer_1): New declarations. * cli/cli-setshow.c (parse_cli_var_uinteger) (parse_cli_var_zuinteger_unlimited, do_set_command): Handle empty argument strings for all var_types. (get_setshow_command_value_string): New, factored out from ... (do_show_command): ... this. * cli/cli-setshow.h: Include <string>. (get_setshow_command_value_string): Declare. * command.h (repeat_previous): Now returns const char *. Adjust comment. * maint.c: Include "cli/cli-cmds.h". (maintenance_with_cmd, maintenance_with_cmd_completer): New. (_initialize_maint_cmds): Register the "maintenance with" command. * top.c (repeat_previous): Move bits from pipe_command here: Return the saved command line, if any; error out if there's no command to relaunch. gdb/doc/ChangeLog: 2019-07-03 Pedro Alves <palves@redhat.com> Philippe Waroquiers <philippe.waroquiers@skynet.be> * gdb.texinfo (Command Settings): New node documenting the general concept of settings, how to change them, and the new "with" command. (Maintenance Commands): Document "maint with". gdb/testsuite/ChangeLog: 2019-07-03 Pedro Alves <palves@redhat.com> * gdb.base/with.c: New file. * gdb.base/with.exp: New file.
67 lines
2.7 KiB
C++
67 lines
2.7 KiB
C++
/* Header file for GDB CLI set and show commands implementation.
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Copyright (C) 2000-2019 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef CLI_CLI_SETSHOW_H
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#define CLI_CLI_SETSHOW_H
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#include <string>
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struct cmd_list_element;
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/* Parse ARG, an option to a boolean variable.
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Returns 1 for true, 0 for false, and -1 if invalid. */
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extern int parse_cli_boolean_value (const char *arg);
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/* Same as above, but work with a pointer to pointer. ARG is advanced
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past a successfully parsed value. */
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extern int parse_cli_boolean_value (const char **arg);
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/* Parse ARG, an option to a var_uinteger or var_zuinteger variable.
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Either returns the parsed value on success or throws an error. If
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EXPRESSION is true, *ARG is parsed as an expression; otherwise, it
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is parsed with get_ulongest. It's not possible to parse the
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integer as an expression when there may be valid input after the
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integer, such as when parsing command options. E.g., "print
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-elements NUMBER -obj --". In such case, parsing as an expression
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would parse "-obj --" as part of the expression as well. */
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extern unsigned int parse_cli_var_uinteger (var_types var_type,
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const char **arg,
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bool expression);
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/* Like parse_cli_var_uinteger, for var_zuinteger_unlimited. */
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extern int parse_cli_var_zuinteger_unlimited (const char **arg,
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bool expression);
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/* Parse ARG, an option to a var_enum variable. ENUM is a
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null-terminated array of possible values. Either returns the parsed
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value on success or throws an error. ARG is advanced past the
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parsed value. */
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const char *parse_cli_var_enum (const char **args,
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const char *const *enums);
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extern void do_set_command (const char *arg, int from_tty,
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struct cmd_list_element *c);
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extern void do_show_command (const char *arg, int from_tty,
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struct cmd_list_element *c);
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/* Get a string version of C's current value. */
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extern std::string get_setshow_command_value_string (cmd_list_element *c);
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extern void cmd_show_list (struct cmd_list_element *list, int from_tty,
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const char *prefix);
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#endif /* CLI_CLI_SETSHOW_H */
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