Add a new mdb command, 'shell', that allows users to execute shell commands

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Add a new mdb command, 'shell', that allows users to execute shell commands
from within the debugger.

Allow the user to give up to nine additional arguments to the 'source' command.
Occurrences of the strings "$1" through "$9" in the sourced file are replaced
by the corresponding additional arguments, allowing for parameterised scripts.

Use the two new features mentioned above to add two more mdb commands: one
to open a term, goal or exception in an external editor another command
to perform a grep on a term, goal or exception (useful for seeing if a value
occurs in a big map, for example).

NEWS
	Mention the new commands.

doc/mdb_categories:
doc/user_guide.texi:
	Document the new commands.

scripts/Mmakefile:
scripts/mdb_open:
scripts/mdb_vim:
	Add scripts for the new commands.

scripts/mdbrc.in:
	Add aliases for the new shell, emacs, grep and vim commands.

tests/debugger/completion.exp:
tests/debugger/mdb_command_test.inp:
	Adjust for new commands.

tests/debugger/save.exp:
tests/debugger/save.exp2:
	Adjust for new commands.  Replace system dependent strings
	with ZZZ instead of XXX.

tests/debugger/Mmakefile:
tests/debugger/shell.exp:
tests/debugger/shell.inp:
tests/debugger/shell.m:
tests/debugger/shell_test_script:
	Test the shell and source commands.

trace/mercury_trace_cmd_misc.c:
	Check if there are extra arguments to the source mdb command
	and pass them to MR_trace_source if there are.

trace/mercury_trace_cmd_misc.h:
	Add shell command handling function prototype.

trace/mercury_trace_declarative.c:
	Call MR_trace_call_system_display_error_on_failure instead
	of system when displaying benchmarking statistics for the
	declarative debugger.

trace/mercury_trace_internal.c:
trace/mercury_trace_internal.h:
	Implement the shell command and extend the source command
	to handle the optional extra arguments.

trace/mercury_trace_readline.c:
trace/mercury_trace_readline.h:
	Add a new function to read a line and replace all the
	occurrences of "$[1-9]" with the corresponding value from an array.

	Delete comments in the .c file that are duplicated in the .h file.

trace/mercury_trace_util.c:
trace/mercury_trace_util.h:
	Implement MR_trace_call_system_display_error_on_failure that
	executes a system call and displays an error message if the system
	call terminates abnormally.

NEWS

@@ -69,6 +69,12 @@ Changes to the Mercury debugger:
   left the goal at which the term was available as the value of a program
   variable.
 * Users can now see the set of places where two terms differ from each other.
+* Users can now execute system shell commands from within the debugger.
+* The source command now accepts optional additional arguments which
+  are substituted into the sourced file, allowing for parameterised
+  scripts.
+* Users can now open terms in their favorite editor, or
+  perform a grep on a term.
 * The `set' command has been replaced by several other commands: the `format',
   `format_param', `list_context_lines', `list_path', `xml_browser_cmd',
   `xml_tmp_filename', `fail_trace_counts', `pass_trace_counts' and
@@ -77,8 +83,9 @@ Changes to the Mercury debugger:
 * The `save' command now saves the entire persistent state of the debugger
   (with one small exception that cannot be reestablished by an mdb command from
   an arbitrary point of execution).
-* The declarative debugger now supports an `undo' command, and allows users to
-  select the search algorithm.
+* The declarative debugger now supports an `undo' command.
+* The declarative debugger now allows users to
+  change the search algorithm mid-session.
 * The declarative debugger can now exploit information from the "code
   footprints" of passed and failed test cases to find bugs with fewer
   questions. We have also added two tools, mslice and mdice, to manipulate
@@ -314,6 +321,46 @@ Changes to the Mercury compiler:
   in which the format string or the structure of the list of values to be
   printed are not statically available.
 
+Changes to the Mercury debugger:
+
+* A `list' command has ben added that displays a listing of the source code
+  lines referred to by the current environment.  To supporting commands
+  `pop_list_dir' and `push_list_dir' have also been added.
+ 
+* Users can now keep hold of a term, referring to it even when execution has
+  left the goal at which the term was available as the value of a program
+  variable.  The name of the new command is `hold'.
+
+* A `diff' command has been added that allows users to see the set of places
+  where two terms differ from each other.
+
+* A `shell' (or `!' for short) command has been added that allows users to
+  execute system shell commands from within the debugger.
+
+* The `source' command now accepts optional additional arguments which
+  are substituted into the sourced file, allowing for parameterised
+  scripts.  The strings "$1" through "$9" in the sourced file are replaced with
+  the corresponding argument of the `source' command.
+
+* The above two features have been used to create two additional commands: an
+  `open' command that lets users open a term in their favorite editor for 
+  browsing and a `grep' command that can be used to check if a term contains
+  a particular pattern.
+  
+* The declarative debugger now allows users to take back answers they gave
+  by means of an multi-level `undo' command.
+
+* The declarative debugger now allows users to change the search algorithm
+  mid-session by means of a `mode' command.
+
+* The declarative debugger can now exploit information from the "code
+  footprints" of passed and failed test cases to find bugs with fewer
+  questions. We have also added two tools, mslice and mdice, to manipulate
+  files containing such footprints.
+
+* Subterm dependency tracking in the declarative debugger is now significantly
+  faster.
+
 Changes to the extras distribution:
 
 * We've added a library of data structures designed to work for solver types. 

doc/mdb_categories

@@ -27,7 +27,7 @@ document_category 400 browsing
 browsing   - Commands that let users explore the state of the computation.
              The browsing commands are `vars', `held_vars', `print', `browse',
              `stack', `up', `down', `level', `current', `view', `hold',
-             `diff', `dump', and `list'.
+             `diff', `dump', `grep', `list' and `open'.
 
 end
 document_category 500 breakpoint
@@ -70,8 +70,8 @@ decl       - Commands available from within the declarative debugger.  These
 end
 document_category 900 misc
 misc       - Commands that are of interest to most users but do not fit into
-             other categories. The misc commands are `source', `save' and 
-             `quit'.
+             other categories. The misc commands are `source', `save', `shell'
+             and `quit'.
 
 end
 document_category 1000 exp

doc/user_guide.texi

@@ -2870,6 +2870,22 @@ Writes the value of the variable in the current environment
 with the given ordinal number or with the given name
 to the specified file. The option @samp{-x} (or @samp{--xml}) causes the
 output to be in XML.
+@sp 1
+@item open @var{term}
+Save @var{term} to a temporary file and open the file in an editor.
+The environment variable EDITOR is consulted to determine what editor to
+use.
+If this environment variable is not set then @samp{vi} is used.
+@var{term} may be any term that can be saved to a file with the
+@samp{save_to_file} command.
+@sp 1
+@item grep @var{pattern} @var{term}
+Save the given term to a temporary file and perform a grep on the
+file using @var{pattern}.
+@var{term} may be any term that can be saved to a file with the
+@samp{save_to_file} command.
+The unix `grep' command must be available from the shell for this command
+to work.
 @c @sp 1
 @c @item dump [-x] proc_body @var{filename}
 @c Writes the representation of the body of the current procedure,
@@ -3799,9 +3815,13 @@ and its submodules, if any.
 
 @sp 1
 @table @code
-@item source [-i] @var{filename}
+@item source [-i] @var{filename} [@var{args}]
 @kindex source (mdb command)
 Executes the commands in the file named @var{filename}.
+Optionally a list of at most nine arguments can be given.
+Occurrences of the strings "$1" to "$9" in the sourced file
+will be replaced by the corresponding arguments given in the source
+command before the commands in the sourced file are executed.
 @sp 1
 The option @samp{-i} or @samp{--ignore-errors} tells @samp{mdb}
 not to complain if the named file does not exist or is not readable.

scripts/Mmakefile

@@ -48,7 +48,11 @@ CONF_FILES = \
 CONF_DEBUG_SCRIPTS = 	\
 	mdbrc
 
-DEBUGGER_SCRIPTS = $(CONF_DEBUG_SCRIPTS) xul_tree.xsl
+DEBUGGER_SCRIPTS = $(CONF_DEBUG_SCRIPTS) 	\
+		xul_tree.xsl			\
+		mdb_open			\
+		mdb_grep
+
 EMACS_SCRIPTS = gud.el
 
 #-----------------------------------------------------------------------------#

scripts/mdb_grep

@@ -0,0 +1,3 @@
+save_to_file $2 .mdb_grep_tmp
+shell grep $1 .mdb_grep_tmp
+shell rm .mdb_grep_tmp

scripts/mdb_open

@@ -0,0 +1,3 @@
+save_to_file $1 .mdb_open_tmp
+shell ${EDITOR-vi} .mdb_open_tmp
+shell rm .mdb_open_tmp

scripts/mdbrc.in

@@ -15,5 +15,8 @@ alias	excp	exception
 alias	e	exception
 alias	EMPTY	step
 alias	NUMBER	step
+alias	!	shell
+alias	open	source @DEFAULT_MERCURY_DEBUGGER_INIT_DIR@/mdb_open
+alias	grep	source @DEFAULT_MERCURY_DEBUGGER_INIT_DIR@/mdb_grep
 xml_browser_cmd '@DEFAULT_XML_BROWSER_CMD@'
 xml_tmp_filename '@DEFAULT_XML_TMP_FILENAME@'

tests/debugger/Mmakefile

@@ -47,6 +47,7 @@ NONRETRY_PROGS = \
 	print_table			\
 	queens_rep			\
 	resume_typeinfos		\
+	shell				\
 	save				\
 	solver_test			\
 	type_desc_test			\
@@ -469,13 +470,18 @@ retry.out: retry retry.inp
 # with a known character sequence.
 save.out: save save.inp
 	$(MDB) ./save < save.inp 2>&1 | \
-		sed 's/xml_browser_cmd.*/xml_browser_cmd XXX/g' | \
-		sed 's/xml_tmp_filename.*/xml_tmp_filename XXX/g' \
+	    sed 's/xml_browser_cmd.*/xml_browser_cmd ZZZ/g' | \
+	    sed 's/xml_tmp_filename.*/xml_tmp_filename ZZZ/g' | \
+	    sed 's/^alias grep source.*$$/alias grep source ZZZ\/mdb_grep/' | \
+	    sed 's/^alias open source.*$$/alias open source ZZZ\/mdb_open/' \
 	    > save.out 2>&1
 
 shallow.out: shallow shallow.inp
 	$(MDB) ./shallow < shallow.inp > shallow.out 2>&1
 
+shell.out: shell shell.inp
+	$(MDB_STD) ./shell < shell.inp > shell.out 2>&1
+
 solver_test.out: solver_test solver_test.inp
 	$(MDB_STD) ./solver_test < solver_test.inp > solver_test.out 2>&1
 

tests/debugger/completion.exp

@@ -3,43 +3,45 @@ mdb> echo on
 Command echo enabled.
 mdb> register --quiet
 mdb> 
-?                    excp                 print_optionals
-P                    f                    printlevel
-alias                fail_trace_counts    procedures
-all_class_decls      finish               push_list_dir
-all_procedures       flag                 query
-all_regs             format               quit
-all_type_ctors       format_param         r
-ambiguity            forward              register
-b                    g                    retry
-break                gen_stack            return
-break_print          goal_paths           s
-browse               goto                 save
-c                    h                    scope
-cc_query             held_vars            scroll
-class_decl           help                 source
-clear_histogram      histogram_all        stack
-condition            histogram_exp        stack_default_limit
-consumer             hold                 stack_regs
-context              ignore               stats
-continue             io_query             step
-current              level                subgoal
-cut_stack            list                 table
-d                    list_context_lines   table_io
-dd                   list_path            term_size
-debug_vars           max_io_actions       trust
-delete               maxdepth             trusted
-dice                 mindepth             type_ctor
-diff                 mm_stacks            unalias
-disable              mmc_options          unhide_events
-document             modules              untrust
-document_category    next                 up
-down                 nondet_stack         v
-dump                 p                    var_details
-e                    pass_trace_counts    vars
-echo                 pneg_stack           view
-enable               pop_list_dir         xml_browser_cmd
-exception            print                xml_tmp_filename
+!                    f                    printlevel
+?                    fail_trace_counts    procedures
+P                    finish               push_list_dir
+alias                flag                 query
+all_class_decls      format               quit
+all_procedures       format_param         r
+all_regs             forward              register
+all_type_ctors       g                    retry
+ambiguity            gen_stack            return
+b                    goal_paths           s
+break                goto                 save
+break_print          grep                 scope
+browse               h                    scroll
+c                    held_vars            shell
+cc_query             help                 source
+class_decl           histogram_all        stack
+clear_histogram      histogram_exp        stack_default_limit
+condition            hold                 stack_regs
+consumer             ignore               stats
+context              io_query             step
+continue             level                subgoal
+current              list                 table
+cut_stack            list_context_lines   table_io
+d                    list_path            term_size
+dd                   max_io_actions       trust
+debug_vars           maxdepth             trusted
+delete               mindepth             type_ctor
+dice                 mm_stacks            unalias
+diff                 mmc_options          unhide_events
+disable              modules              untrust
+document             next                 up
+document_category    nondet_stack         v
+down                 open                 var_details
+dump                 p                    vars
+e                    pass_trace_counts    view
+echo                 pneg_stack           xml_browser_cmd
+enable               pop_list_dir         xml_tmp_filename
+exception            print                
+excp                 print_optionals      
 h              help           histogram_exp  
 held_vars      histogram_all  hold           
 var_details  vars         view         

tests/debugger/mdb_command_test.inp

@@ -46,6 +46,8 @@ view                 xyzzy xyzzy xyzzy xyzzy xyzzy
 hold                 xyzzy xyzzy xyzzy xyzzy xyzzy
 diff                 xyzzy xyzzy xyzzy xyzzy xyzzy
 dump                 xyzzy xyzzy xyzzy xyzzy xyzzy
+open                 xyzzy xyzzy xyzzy xyzzy xyzzy
+grep                 xyzzy xyzzy xyzzy xyzzy xyzzy
 list                 xyzzy xyzzy xyzzy xyzzy xyzzy
 break                xyzzy xyzzy xyzzy xyzzy xyzzy
 condition            xyzzy xyzzy xyzzy xyzzy xyzzy

tests/debugger/save.exp

@@ -21,6 +21,7 @@ mdb> save save_file
 Debugger state saved to save_file.
 mdb> continue -n -S
 [1, 3, 5, 2, 4]
+alias ! shell
 alias ? help
 alias EMPTY step
 alias NUMBER step
@@ -32,7 +33,9 @@ alias e exception
 alias excp exception
 alias f finish
 alias g goto
+alias grep source ZZZ/mdb_grep
 alias h help
+alias open source ZZZ/mdb_open
 alias p print
 alias r retry
 alias s step

tests/debugger/save.exp2

@@ -21,6 +21,7 @@ mdb> save save_file
 Debugger state saved to save_file.
 mdb> continue -n -S
 [1, 3, 5, 2, 4]
+alias ! shell
 alias ? help
 alias EMPTY step
 alias NUMBER step
@@ -32,7 +33,9 @@ alias e exception
 alias excp exception
 alias f finish
 alias g goto
+alias grep source ZZZ/mdb_grep
 alias h help
+alias open source ZZZ/mdb_open
 alias p print
 alias r retry
 alias s step
@@ -101,8 +104,8 @@ format_param -A -p size 10
 format_param -A -p width 80
 format_param -A -p lines 2
 max_io_actions 20
-xml_browser_cmd XXX
-xml_tmp_filename XXX
+xml_browser_cmd ZZZ
+xml_tmp_filename ZZZ
 trust save
 trust std lib
 list_context_lines 2

tests/debugger/shell.exp

@@ -0,0 +1,16 @@
+      E1:     C1 CALL pred shell.main/2-0 (det) shell.m:11
+mdb> echo on
+Command echo enabled.
+mdb> shell echo hello
+hello
+mdb> alias test source shell_test_script
+test   =>    source shell_test_script
+mdb> test value1 value2 3 'value 4' "a" '' 'b' file_name.ext 9
+value1 value2
+value2 value1
+value1 value2 $ $abc 3 value 4 a b file_name.ext 9 $0 $b $
+mdb> test only_one_value
+only_one_value
+only_one_value
+only_one_value $ $abc $0 $b $
+mdb> quit -y

tests/debugger/shell.inp

@@ -0,0 +1,6 @@
+echo on
+shell echo hello
+alias test source shell_test_script
+test value1 value2 3 'value 4' "a" '' 'b' file_name.ext 9
+test only_one_value
+quit -y

tests/debugger/shell.m

@@ -0,0 +1,12 @@
+:- module shell.
+
+:- interface.
+
+:- import_module io.
+
+:- pred main(io::di, io::uo) is det.
+
+:- implementation.
+
+main(!IO) :-
+	nl(!IO).

tests/debugger/shell_test_script

@@ -0,0 +1,3 @@
+shell echo $1 $2
+shell echo $2 $1
+shell echo $1 $2 $ \\$abc $3 $4 $5 $6 $7 $8 $9 \\$0 \\$b $

trace/mercury_trace_cmd_misc.c

@@ -47,17 +47,24 @@ MR_trace_cmd_source(char **words, int word_count, MR_Trace_Cmd_Info *cmd,
     MR_Event_Info *event_info, MR_Code **jumpaddr)
 {
     MR_bool ignore_errors;
+    char    **args;
 
     ignore_errors = MR_FALSE;
     if (! MR_trace_options_ignore(&ignore_errors, &words, &word_count)) {
         ; /* the usage message has already been printed */
-    } else if (word_count == 2) {
+    } else if (word_count >= 2) {
         /*
         ** If the source fails, the error message
         ** will have already been printed by MR_trace_source
         ** (unless ignore_errors suppresses the message).
         */
-        (void) MR_trace_source(words[1], ignore_errors);
+        if (word_count == 2) {
+            args = NULL;
+        } else {
+            args = &words[2];
+        }
+        (void) MR_trace_source(words[1], ignore_errors, args,
+            word_count - 2);
     } else {
         MR_trace_usage_cur_cmd();
     }

trace/mercury_trace_cmd_misc.h

@@ -11,6 +11,7 @@
 
 extern  MR_TraceCmdFunc     MR_trace_cmd_source;
 extern  MR_TraceCmdFunc     MR_trace_cmd_save;
+extern  MR_TraceCmdFunc     MR_trace_cmd_shell;
 extern  MR_TraceCmdFunc     MR_trace_cmd_quit;
 
 extern	const char *const   MR_trace_source_cmd_args[];

trace/mercury_trace_declarative.c

@@ -2434,7 +2434,7 @@ MR_decl_print_edt_stats(void)
     pid = getpid();
     sprintf(cmdstr, "ps -p %i -o rss,vsz | tail -1 |"
     	"awk '{print \"RSS = \" $1 \"\\nVSZ = \" $2}' 1>&2", pid);
-    system(cmdstr);
+    MR_trace_call_system_display_error_on_failure(stderr, cmdstr);
 
     MR_debug_enabled = MR_FALSE;
     MR_update_trace_func_enabled();

trace/mercury_trace_internal.c

@@ -634,7 +634,7 @@ MR_trace_internal_init_from_env(void)
 
     init = getenv("MERCURY_DEBUGGER_INIT");
     if (init != NULL) {
-        (void) MR_trace_source(init, MR_FALSE);
+        (void) MR_trace_source(init, MR_FALSE, NULL, 0);
         /* If the source failed, the error message has been printed. */
     }
 }
@@ -647,7 +647,7 @@ MR_trace_internal_init_from_local(void)
 
     init = MDBRC_FILENAME;
     if ((fp = fopen(init, "r")) != NULL) {
-        MR_trace_source_from_open_file(fp);
+        MR_trace_source_from_open_file(fp, NULL, 0);
         fclose(fp);
     }
 }
@@ -671,7 +671,7 @@ MR_trace_internal_init_from_home_dir(void)
     (void) strcat(buf, "/");
     (void) strcat(buf, MDBRC_FILENAME);
     if ((fp = fopen(buf, "r")) != NULL) {
-        MR_trace_source_from_open_file(fp);
+        MR_trace_source_from_open_file(fp, NULL, 0);
         fclose(fp);
     }
 
@@ -679,12 +679,13 @@ MR_trace_internal_init_from_home_dir(void)
 }
 
 MR_bool
-MR_trace_source(const char *filename, MR_bool ignore_errors)
+MR_trace_source(const char *filename, MR_bool ignore_errors,
+    char** args, int num_args)
 {
     FILE    *fp;
 
     if ((fp = fopen(filename, "r")) != NULL) {
-        MR_trace_source_from_open_file(fp);
+        MR_trace_source_from_open_file(fp, args, num_args);
         fclose(fp);
         return MR_TRUE;
     }
@@ -698,7 +699,7 @@ MR_trace_source(const char *filename, MR_bool ignore_errors)
 }
 
 void
-MR_trace_source_from_open_file(FILE *fp)
+MR_trace_source_from_open_file(FILE *fp, char **args, int num_args)
 {
     char    *contents;
     MR_Line *line;
@@ -713,7 +714,9 @@ MR_trace_source_from_open_file(FILE *fp)
     ** preserving their order in the sourced file.
     */
 
-    while ((contents = MR_trace_readline_raw(fp)) != NULL) {
+    while ((contents = MR_trace_readline_expand_args(fp, args, num_args))
+        != NULL)
+    {
         line = MR_NEW(MR_Line);
         line->MR_line_contents = MR_copy_string(contents);
 
@@ -751,6 +754,31 @@ MR_trace_do_noop(void)
 ** MR_process_matching_procedures().
 */
 
+static MR_Next
+MR_trace_cmd_shell(char **words, int word_count, MR_Trace_Cmd_Info *cmd,
+    MR_Event_Info *event_info, MR_Code **jumpaddr)
+{
+    char*       command_string;
+    size_t      command_string_length;
+    int         word_num;
+
+    command_string_length = 1;
+    for (word_num = 1; word_num < word_count; word_num++) {
+        command_string_length += strlen(words[word_num]) + 1;
+    }
+    command_string = (char*) MR_malloc(sizeof(char) * command_string_length);
+    command_string[0] = '\0';
+    for (word_num = 1; word_num < word_count; word_num++) {
+        strcat(command_string, words[word_num]);
+        strcat(command_string, " ");
+    }
+
+    MR_trace_call_system_display_error_on_failure(MR_mdb_err, command_string);
+    MR_free(command_string);
+
+    return KEEP_INTERACTING;
+}
+
 static void
 MR_mdb_print_proc_id_and_nl(void *data, const MR_Proc_Layout *entry_layout)
 {
@@ -1628,6 +1656,8 @@ static const MR_Trace_Command_Info  MR_trace_command_infos[] =
         NULL, MR_trace_filename_completer },
     { "misc", "quit", MR_trace_cmd_quit,
         MR_trace_quit_cmd_args, MR_trace_null_completer },
+    { "misc", "shell", MR_trace_cmd_shell,
+        NULL, MR_trace_null_completer },
 
     { "exp", "histogram_all", MR_trace_cmd_histogram_all,
         NULL, MR_trace_filename_completer },

trace/mercury_trace_internal.h

@@ -83,13 +83,14 @@ extern  MR_Trace_Source_Server  MR_trace_source_server;
 */
 
 extern  MR_bool     MR_trace_source(const char *filename,
-                        MR_bool ignore_errors);
+                        MR_bool ignore_errors, char** args, int num_args);
 
 /*
 ** Source commands from the given file.
 */
 
-extern  void        MR_trace_source_from_open_file(FILE *fp);
+extern  void        MR_trace_source_from_open_file(FILE *fp,
+                        char **args, int num_args);
 
 /*
 ** Print a usage message for the currently executing command.

trace/mercury_trace_readline.c

@@ -1,5 +1,5 @@
 /*
-** Copyright (C) 1998-2002, 2005 The University of Melbourne.
+** Copyright (C) 1998-2002, 2005-2006 The University of Melbourne.
 ** This file may only be copied under the terms of the GNU Library General
 ** Public License - see the file COPYING.LIB in the Mercury distribution.
 */
@@ -50,13 +50,6 @@
 static	void	MR_dummy_prep_term_function(int ignored);
 static	void	MR_dummy_deprep_term_function(void);
 
-/*
-** Print the prompt to the `out' file, read a line from the `in' file,
-** and return it in a MR_malloc'd buffer holding the line (without the
-** final newline).
-** If EOF occurs on a nonempty line, treat the EOF as a newline; if EOF
-** occurs on an empty line, return NULL.
-*/
 char *
 MR_trace_readline(const char *prompt, FILE *in, FILE *out)
 {
@@ -147,12 +140,6 @@ MR_trace_readline(const char *prompt, FILE *in, FILE *out)
 	return MR_trace_readline_raw(in);
 }
 
-/*
-** Read a line from a file, and return a pointer to a MR_malloc'd buffer
-** holding the line (without the final newline). If EOF occurs on a
-** nonempty line, treat the EOF as a newline; if EOF occurs on an empty
-** line, return NULL.
-*/
 char *
 MR_trace_readline_raw(FILE *fp)
 {
@@ -180,6 +167,65 @@ MR_trace_readline_raw(FILE *fp)
 	}
 }
 
+char *
+MR_trace_readline_expand_args(FILE *fp, char **args, int num_args)
+{
+	char	*line;
+	size_t	line_length;
+	int	line_index;
+	size_t	expanded_line_length;
+	char	*expanded_line;
+	int	expanded_line_index;
+	int	arg_num;
+	size_t	arg_length;
+	char	*arg;
+	
+	line = MR_trace_readline_raw(fp);
+	if (line == NULL) {
+		return NULL;
+	}
+	line_length = strlen(line);
+
+	expanded_line_length = line_length;
+	expanded_line = (char*) MR_malloc(line_length + 1);
+	expanded_line[0] = '\0';
+	expanded_line_index = 0;
+
+	for (line_index = 0; line_index < line_length; line_index++) {
+		if ((line[line_index] == '$') && 
+			(line_index < (line_length - 1)) &&
+			(line[line_index + 1] >= '1') &&
+			(line[line_index + 1] <= '9'))
+		{
+			arg_num = (int)(line[line_index + 1] - '1');
+			if (arg_num < num_args) {
+				arg = args[arg_num];
+				arg_length = strlen(arg);
+				/*
+				** Subtract 2 for the "$n" which will
+				** not occur in the expanded string.
+				*/
+				expanded_line_length += arg_length - 2;
+				expanded_line = MR_realloc(expanded_line, 
+					expanded_line_length + 1);
+				expanded_line[expanded_line_index] = '\0';
+				strcat(expanded_line, arg);
+				expanded_line_index += arg_length;
+			}
+			/* Skip the digit after the '$'. */
+			line_index++;
+		} else {
+			expanded_line[expanded_line_index] = line[line_index];
+			expanded_line_index++;
+		}
+	}
+
+	MR_free(line);
+	expanded_line[expanded_line_index] = '\0';
+	
+	return expanded_line;
+}
+
 static void
 MR_dummy_prep_term_function(int ignored)
 {

trace/mercury_trace_readline.h

@@ -1,5 +1,5 @@
 /*
-** Copyright (C) 1998-1999 The University of Melbourne.
+** Copyright (C) 1998-1999, 2006 The University of Melbourne.
 ** This file may only be copied under the terms of the GNU Library General
 ** Public License - see the file COPYING.LIB in the Mercury distribution.
 */
@@ -28,3 +28,15 @@ char *	MR_trace_readline(const char *prompt, FILE *in, FILE *out);
 ** line, return NULL.  Don't use GNU readline.
 */
 char *	MR_trace_readline_raw(FILE *in);
+
+/*
+** Read a line from a file and replace occurrences of the strings "$1" to
+** "$9" with the corresponding values in the args array.  If there is no
+** value in the args array, then the "$n" string is replaced by the empty
+** string.
+** Return a pointer to a MR_malloc'd buffer holding the new string (without
+** the final newline).  If EOF occurs on a nonempty line, treat the EOF as a
+** newline; if EOF occurs on an empty line, return NULL.  
+** Don't use GNU readline.
+*/
+char * MR_trace_readline_expand_args(FILE *fp, char **args, int num_args);

trace/mercury_trace_util.c

@@ -207,3 +207,21 @@ MR_trace_proc_layout_is_builtin_catch(const MR_Proc_Layout *layout)
     }
     return MR_FALSE;
 }
+
+void
+MR_trace_call_system_display_error_on_failure(FILE *err_stream, char *command)
+{
+    int     system_rv;
+    
+    if (system(NULL)) {
+        system_rv = system(command);
+        if (system_rv != 0) {
+            fprintf(err_stream,
+                "mdb: the shell command returned a non-zero exit code or was"
+                " terminated abnormally.\n",
+                system_rv);
+        }
+    } else {
+        fprintf(err_stream, "mdb: no shell found.\n");
+    }
+}

trace/mercury_trace_util.h

@@ -78,4 +78,13 @@ extern	void	MR_print_debug_vars(FILE *fp, MR_Event_Info *event_info);
 extern	MR_bool	MR_trace_proc_layout_is_builtin_catch(
 			const MR_Proc_Layout *layout);
 
+/*
+** MR_trace_call_system_display_error_on_failure executes the given command
+** and displays an error message if the command returned a non-zero exit
+** status, there was a problem executing the command, or no usable shell was
+** available.
+*/
+extern	void	MR_trace_call_system_display_error_on_failure(
+			FILE *err_stream, char *command);
+
 #endif /* MERCURY_TRACE_UTIL_H */