| axd(1) | General Commands Manual | axd(1) |
axd - afnix cross debugger
axd [options] file
[h]
prints the help message
[v]
prints the program version
[i] path
add a directory path to the resolver
[e] mode
force the encoding mode
[f] runini
run initial file
[f] emacs
enable emacs mode
[f] assert
enable assertion checking
[f] noseed
do not seed the random engine
[f] seed
seed the random engine
axd invokes the AFNIX cross debugger. The axd client permits to debug an AFNIX program by inserting breakpoint at strategic positions in the source code. During a debugging session, when a breakpoint is reached, the program is suspended and the debugger prompt is shown. Since the debugger is based on the AFNIX interpreter, the full power of the AFNIX interpreter is available at the debugger prompt.
The current version is the 3.7.0 release.
axc, axd, axl,
AFNIX comes with an extensive documentation. The documentation is available online or in the doc directory in the form of formatted xhtml documents.
axd has been written by (amaury@afnix.org) Amaury Darsch.
This chapter is short introduction to the cross debugger or axd. The debugger is a special interpreter that is designed to help the developer to trace an application. The debugger is designed to operate in a stand-alone mode or with Emacs. If you plan to use the debugger with Emacs, you will have to install a gud-mode package.
A sample debugger session
The cross debugger or axd is a special interpreter that gives the developer
the opportunity to trace an application and examine the object contents
during the execution. Operations normally available in a debugger are
available with axd. Such operations include breakpoints, stepping, stack
tracing, and many others. Because axd is built on top of the interpreter,
all standard operations are supported by the debugger.
Starting the debugger
The debugger is started with the command axd. Within Emacs, the command Meta-x
axd will do the same. When the debugger is started, an axd prompt is
displayed. At this stage, there is no difference with the standard
interpreter, except that a new nameset called axd is defined with all
debugger commands. The axd:quit or axd:quit commands will terminate the
session.
zsh> axd (axd)axd:quit
Debugger commands
All debugger commands are located in the axd nameset. For example, the command
to set a breakpoint is axd:break. Since typing such command can be annoying,
it is possible to rebind them at your convenience. For example, the form
const b axd:break will define the symbol b as the breakpoint command, but
care should be taken with this approach if your program uses the same
symbol.
Debugging session example
The first example that demonstrates the use of axd is located in the directory
exp/ref, that is part of this distribution. The platform information example
EXP0501.als will be used for illustration. A simple session and the original
source code is given below.
zsh> axi EXP0501.als major version number : 3 minor version number : 2 patch version number : 0 interpreter version : 3.2.0 program name : afnix operating system name : linux operating system type : unix machine size : 64 afnix official uri : http://www.afnix.org
The source code for this example is given below.
# many comments before println "major version number : " interp:major-version println "minor version number : " interp:minor-version println "patch version number : " interp:patch-version println "interpreter version : " interp:version println "program name : " interp:program-name println "operating system name : " interp:os-name println "operating system type : " interp:os-type println "machine size : " interp:machine-size println "afnix official url : " interp:afnix-uri
The debugger is started with the file to debug. The axd:info command can be used to print some information.
zsh> axd EXP0501.als (axd) axd:info debugger version : 3.2.0 os name : linux os type : unix initial file : EXP0501.als form file name : EXP0501.als form line number : 17 verbose mode : true max line display : 10 defined breakpoints : 0 (axd)
Along with the version, initial file name and other information, is the form file name and the form line number that indicates where the debugger is position. Another way to get this information is with the axd:list command that display the file at its current break position.
(axd) axd:list 17 println "major version number : " interp:major-version 18 println "minor version number : " interp:minor-version 19 println "patch version number : " interp:patch-version 20 println "interpreter version : " interp:version 21 println "program name : " interp:program-name 22 println "operating system name : " interp:os-name 23 println "operating system type : " interp:os-type 24 println "afnix official uri : " interp:afnix-uri 25 26 (axd)
With this in place it is possible to run the program. The axd:run command will do the job, but will not give you the opportunity to do something since there is no breakpoint installed. So, installing a breakpoint is simply achieved by giving the file name and line number. To make life easier, the axd:break command takes also 0 or argument. Without argument, a breakpoint is set at the current position. With one integer argument, a breakpoint is set at the specified line in the current file. If the verbose mode is active (which is the default), a message is printed to indicate the breakpoint index.
(axd) axd:break 19 setting breakpoint 0 in file EXP0501.als at line 19 (axd)axd:run major version number : 3 minor version number : 2 breakpoint 0 in file EXP0501.als at line 19 (axd)
The axd:run command starts the program and immediately stops at the breakpoint. Note that the debugger prints a message to indicate the cause of such break. After this, stepping is achieved with the axd:next command. Resuming the execution is done with the axd:continue command. The axd:exit or axd:quit command terminates the session.
(axd)axd:next patch version number : 3 (axd)axd:next interpreter version : 3-2-0 (axd)axd:continue program name : axd operating system name : linux operating system type : unix afnix official uri : http://www.afnix.org (axd)axd:quit
This chapter describes in detail the usage of the cross debugger or axc. The debugger is a special application that is built on top of the interpreter. For this reason, the debugger provides the full execution environment with special commands bound into a dedicated nameset.
Invocation and termination
The axd debugger is started by typing the command axd. Once started, the
debugger reads the commands from the terminal. Since the debugger is built
on top of the interpreter, any command is in fact a special form that is
executed by the interpreter. The natural way to invoke the debugger is to
pass the primary file to debug with eventually some arguments.
zsh> axd PROGRAM [arguments]
When the debugger is started, a prompt '(axd)' indicates that the session is running. The debugger session is terminated with the commands axd:exit or axd:quit.
zsh> axd PROGRAM (axd) axd:quit zsh>
Debugger options
The available options can be seen with the h option and the current version
with the v option. This mode of operations is similar to the one found with
the interpreter.
zsh> axd [h] usage: axd [options] [file] [arguments] [h] print this help message [v] print version information [i] path add a path to the resolver [e mode] force the encoding mode [f runini] run initial file [f emacs] enable emacs mode [f assert] enable assertion checks [f nopath] do not set initial path
Running the program
When a program is run within the debugger, a primary file must be used to
indicate where to start the program. The file name can be given either as an
axd command argument or with the axd:load command. The first available form
in the primary file is used as the program starting point.
Loading the program
The axd:load command loads the primary file and mark the first available form
as the starting form for the program execution. The command takes a file
name as its first argument. The resolver rule apply for the file name
resolution.
Note that these operations are also dependent on the i option that adds a path or a librarian to the search-path.
Starting the program
The axd:run command starts the program at the first available form in the
primary file. The program is executed until a breakpoint or any other
halting condition is reached. Generally, when the program execution is
suspended, an entry into the debugger is done and the prompt is shown at the
command line.
(axd)axd:run
The axd:run is the primary command to execute before the program can be debugged. Eventually, a file name can be used as the primary file to execute.
(axd)axd:run "test.als"
Setting program arguments
Since the debugger is built on top of the interpreter, it is possible to set
directly the argument vector. The argument vector is bound to the
interpreter with the qualified name interp:argv. The standard vector can be
used to manipulate the argument vector.
(axd)interp:argv:reset (axd)interp:argv:append "hello"
In this example, the interpreter argument vector is reset and then a single argument string is added to the vector. If one wants to see the interpreter argument vector, a simple procedure can be used as shown below.
const argc (interp:argv:length)
loop (trans i 0) (< i argc) (i:++) {
trans arg (interp:argv:get i)
println "argv[" i "] = " arg
}
Breakpoints operations
Breakpoints are set with the axd:break command. If a breakpoint is reached
during the program execution, the program is suspended and the debugger
session is resumed with a command prompt. At the command prompt, the full
interpreter is available. It permits to examine symbols.
Breakpoint command
The axd:break command sets a breakpoint in a file at a specified line number.
If the file is not specified, the primary file is used instead. If the line
number is not specified, the first available form in the current file is
used.
(axd) axd:break "demo.als" 12 Setting breakpoint 0 in file demo.als at line 12
In this example, a breakpoint is set in the file demo.als at the line number 12. The file name does not have to be the primary file. If another file name is specified, the file is loaded, instrumented and the breakpoint is set.
Viewing breakpoints
The axd:break-info command reports some information about the current
breakpoint setting.
(axd) axd:break "demo.als" 12 (axd) axd:break "test.als" 18 (axd) axd:break-info Breakpoint 0 in file demo.als at line 12 Breakpoint 1 in file test.als at line 18
Resuming execution
The axd:continue command resumes the program execution after a breakpoint. The
program execution continues until another breaking condition is reached or
the program terminates.
(axd) axd:run Breakpoint 0 in file demo.als at line 12 (axd) axd:continue
In this example, the program is run and stopped at breakpoint 0. The axd:continue command resumes the program execution.
This appendix is a reference of the cross debugger or axd. The cross debugger is started with the axd command. All control commands are bound to the axd nameset.
break
The axd:breakbreak command sets a breakpoint. Without argument a breakpoint is
set in the current file at the current line. With a line number, the
breakpoint is set in the current file. With two arguments, the first one is
used as the file name and the second one is used as the line number.
Syntax
(axd) axd:break "demo.als" 12 (axd) axd:break 25
The first example sets a breakpoint in the file demo.als at line 12. The second example sets a breakpoint in the current file at line 25. Without argument, the command sets the breakpoint at the current line. The current line can be seen with the axd:info command.
break-info
The axd:break-info control command reports some information about the current
breakpoints.
Syntax
(axd) axd:break "demo.als" 12 (axd) axd:break "test.als" 18 (axd) axd:break-info Breakpoint 0 in file demo.als at line 12 Breakpoint 1 in file test.als at line 18
In this example, two breakpoints are set. One in file demo.als at line 12 and one in file test.als at line 18. The axd:break-info command reports the current breakpoint settings.
continue
The axd:continue control command resumes the program execution after a
breakpoint. The program execution continues until a breakpoint or another
terminating condition is reached.
Syntax
(axd) axd:run Breakpoint 0 in file demo.als at line 12 (axd) axd:continue
In this example, the program is run and stopped at breakpoint 0. The axd:continue command resumes the program execution.
exit
The axd:exit command terminates a debugger session. This command is similar to
the axd:quit command.
Syntax
(axd) axd:exit
info
The axd:info command reports some debugger information. Such information
includes the debugger version, the operating system, the primary input file,
the primary input file source and more.
Syntax
(axd) axd:info debugger version : .. os name : linux os type : unix initial file : 0501 form file name : 0501.als form line number : 17 verbose mode : true max line display : 10 defined breakpoints : 0
list
The axd:list command display the form listing starting at the current session
line number. The current form line number can also be seen with the axd:info
command. The number of line is a debugger parameter. The first line to
display can also be set as the first parameter. A file name can also be
set.
Syntax
(axd) axd:list (axd) axd:list 20 (axd) axd:list "file.als" 20
The first example shows the listing at the current debugger line. The second example starts the listing at line 20. The third example starts at line 20 with file file.als.
load
The axd:load command sets the initial or default file to be used with the
axd:run control command.
Syntax
(axd) axd:load "demo.als"
In this example, the file demo.als is set as the primary file. Using the axd:info command will report at which line, the first available form has been found.
next
The axd:next command executes the next line in the source file. The axd:next
command does not take argument.
Syntax
(axd) axd:next
quit
The axd:quit command terminates a debugger session. This command is similar to
the axd:exit command.
Syntax
(axd) axd:quit
run
The axd:run command executes the default file in the slave interpreter.
Without argument, the initial or default file is executed. The axd:load
command can be used to set the initial file. With one argument, the file
name argument is used as the initial file.
Syntax
(axd) axd:run (axd) axd:run "demo.als"
The first example runs the initial file. The second example sets the initial file as demo.als and run it.
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