.\" Copyright (c) 1983 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"	@(#)pdx.1	6.1 (Berkeley) 4/29/85
.\"
.TH PDX 1 "April 29, 1985"
.UC 5
.SH NAME
pdx \- pascal debugger
.SH SYNOPSIS
pdx [\fB\-r\fP] [\fIobjfile\fP]
.SH DESCRIPTION
\fIPdx\fP is a tool for source level debugging and execution of
Pascal programs.
The \fIobjfile\fP is an object file produced by the Pascal translator
\fIpi\fP(1).  If no \fIobjfile\fP is specified, \fIpdx\fP looks
for a file named ``obj'' in the current directory.
The object file contains a symbol table which includes the name of the
all the source files translated by \fIpi\fP to create it.
These files are available for perusal while using the debugger.
.PP
If the file ``.pdxinit'' exists in the current directory, then the
debugger commands in it are executed.
.PP
The \fB\-r\fP option causes the \fIobjfile\fP to be executed immediately;
if it terminates successfully \fIpdx\fP exits.
Otherwise it reports the reason for termination
and offers the user the option of entering the debugger
or simply letting \fIpx\fP continue with a traceback.
If \fB\-r\fP is not specified, \fIpdx\fP just prompts and waits for a command.
.PP
The commands are:
.TP
\fBrun\fP [\fIargs\fP] [\fB<\fP \fIfilename\fP] [\fB>\fP \fIfilename\fP]
Start executing \fIobjfile\fP, passing \fIargs\fP as command line arguments;
\fB<\fP or \fB>\fP can be used to redirect input or output in the usual manner.
.TP
\fBtrace\fP [\fBin\fP \fIprocedure/function\fP] [\fBif\fP \fIcondition\fP]
.ns
.TP
\fBtrace\fP \fIsource-line-number\fP [\fBif\fP \fIcondition\fP]
.ns
.TP
\fBtrace\fP \fIprocedure/function\fP [\fBin\fP \fIprocedure/function\fP] [\fBif\fP \fIcondition\fP]
.ns
.TP
\fBtrace\fP \fIexpression\fP \fBat\fP \fIsource-line-number\fP [\fBif\fP \fIcondition\fP]
.ns
.TP
\fBtrace\fP \fIvariable\fP [\fBin\fP \fIprocedure/function\fP] [\fBif\fP \fIcondition\fP]
Have tracing information printed when the program is executed.
A number is associated with the command that is used
to turn the tracing off (see the \fBdelete\fP command).
.sp 1
The first argument describes what is to be traced.
If it is a \fIsource-line-number\fP, then the line is printed
immediately prior to being executed.
Source line numbers in a file other than the current one
must be preceded by the name of the file and a colon, e.g.
``mumble.p:17''.
.sp 1
If the argument is a procedure or function name then
every time it is called, information is printed telling
what routine called it, from what source line it was called,
and what parameters were passed to it.
In addition, its return is noted, and if it's a function
then the value it is returning is also printed.
.sp 1
If the argument is an \fIexpression\fP with an \fBat\fP clause
then the value of the expression is printed whenever the
identified source line is reached.
.sp 1
If the argument is a variable then the name and value of the variable
is printed whenever it changes.
Execution is substantially slower during this form of tracing.
.sp 1
If no argument is specified then all source lines are printed
before they are executed.
Execution is substantially slower during this form of tracing.
.sp 1
The clause ``\fBin\fP \fIprocedure/function\fP'' restricts tracing information
to be printed only while executing inside the given procedure
or function.
.sp 1
\fICondition\fP is a Pascal boolean expression and is
evaluated prior to printing the tracing information;
if it is false then the information is not printed.
.sp 1
There is no restriction on the amount of information
that can be traced.
.br
.ne 10
.IP "\fBstop\fP \fBif\fP \fIcondition\fP"
.ns
.IP "\fBstop\fP \fBat\fP \fIsource-line-number\fP [\fBif\fP \fIcondition\fP]"
.ns
.IP "\fBstop\fP \fBin\fP \fIprocedure/function\fP [\fBif\fP \fIcondition\fP]"
.ns
.IP "\fBstop\fP \fIvariable\fP [\fBif\fP \fIcondition\fP]"
Stop execution when the given line is reached, procedure or function
called, variable changed, or condition true.
.IP "\fBdelete\fP \fIcommand-number\fP"
The trace or stop corresponding to the given number is removed.
The numbers associated with traces and stops are printed by
the \fBstatus\fP command.
.IP "\fBstatus\fP [\fB>\fP \fIfilename\fP]"
Print out
the currently active \fBtrace\fP and \fBstop\fP commands.
.IP \fBcont\fP
Continue execution from where it stopped.
This can only be
done when the program was stopped by an interrupt
or through use of the \fBstop\fP command.
.IP \fBstep\fP
Execute one source line.
.IP \fBnext\fP
Execute up to the next source line.
The difference between this and \fBstep\fP is that
if the line contains a call to a procedure or function
the \fBstep\fP command will stop at the beginning of that
block, while the \fBnext\fP command will not.
.IP "\fBprint\fP \fIexpression\fP [\fB,\fP \fIexpression\fP ...]"
Print out the values of the Pascal expressions.
Variables declared in an outer block but having
the same identifier as one in the current block may be
referenced as ``\fIblock-name\fP\ \fB.\fP\ \fIvariable\fP''.
.IP "\fBwhatis\fP \fIidentifier\fP"
Print the declaration of the given identifier.
.IP "\fBwhich\fP \fIidentifier\fP"
Print the full qualification of the given identifer, i.e.
the outer blocks that the identifier is associated with.
.IP "\fBassign\fP \fIvariable\fP \fIexpression\fP"
Assign the value of the expression to the variable.
.IP "\fBcall\fP \fIprocedure(parameters)\fP"
Execute the object code associated with the named procedure or function.
.IP \fBhelp\fP
Print out a synopsis of \fIpdx\fP commands.
.IP \fBgripe\fP
Invokes a mail program to send a message to the person in charge of \fIpdx\fP.
.IP \fBwhere\fP
Print out
a list of the active procedures and functions and the respective source
line where they are called.
.TP
\fBsource\fP \fIfilename\fP
Read \fIpdx\fP commands from the given \fIfilename\fP.
Especially useful when the \fIfilename\fP has been created by redirecting
a \fBstatus\fP command from an earlier debugging session.
.IP "\fBdump\fP [\fB>\fP \fIfilename\fP]"
Print the names and values of all active
data.
.IP "\fBlist\fP [\fIsource-line-number\fP [\fB,\fP \fIsource-line-number\fP]]"
.ns
.IP "\fBlist\fP \fIprocedure/function\fP"
List the lines in the current source file from the first line number to
the second inclusive.
As in the editor
``$'' can be used to refer to the last line.
If no lines are specified, the entire file is listed.
If the name of a procedure or function is given
lines \fIn-k\fP to \fIn+k\fP are listed where \fIn\fP is the first statement
in the procedure or function and \fIk\fP is small.
.IP "\fBfile\fP [\fIfilename\fP]"
Change the current source file name to \fIfilename\fP.
If none is specified then the current source file name is printed.
.IP "\fBedit\fP [\fIfilename\fP]"
.ns
.IP "\fBedit\fP \fIprocedure/function-name\fP"
Invoke an editor on \fIfilename\fP or the current source file if none
is specified.
If a \fIprocedure\fP or \fIfunction\fP name is specified,
the editor is invoked on the file that contains it.
Which editor is invoked by default depends on the installation.
The default can be overridden by setting the environment variable
EDITOR to the name of the desired editor.
.IP \fBpi\fP
Recompile the program and read in the new symbol table information.
.IP "\fBsh\fP \fIcommand-line\fP"
Pass the command line to the shell for execution.
The SHELL environment variable determines which shell is used.
.IP "\fBalias\fP \fInew-command-name\fP \fIold-command-name\fP"
This command makes \fIpdx\fP respond to \fInew-command-name\fP
the way it used to respond to \fIold-command-name\fP.
.IP "\fBquit\fP"
Exit \fIpdx\fP.
.sp 4
.PP
The following commands deal with the program at the \fIpx\fP instruction
level rather than source level.
They are not intended for general use.
.TP
\fBtracei\fP [\fIaddress\fP] [\fBif\fP \fIcond\fP]
.ns
.TP
\fBtracei\fP [\fIvariable\fP] [\fBat\fP \fIaddress\fP] [\fBif\fP \fIcond\fP]
.ns
.TP
\fBstopi\fP [\fIaddress\fP] [\fBif\fP \fIcond\fP]
.ns
.TP
\fBstopi\fP [\fBat\fP] [\fIaddress\fP] [\fBif\fP \fIcond\fP]
Turn on tracing or set a stop using a \fIpx\fP machine
instruction addresses.
.TP
\fBxi\fP \fIaddress\fP [\fB,\fP \fIaddress\fP]
Print the instructions starting at the first \fIaddress\fP.
Instructions up to
the second \fIaddress\fP are printed.
.TP
\fBxd\fP \fIaddress\fP [\fB,\fP \fIaddress\fP]
Print in octal the specified data location(s).
.SH FILES
.nr In 25
.in +\n(Inn
.ta \n(Inn
.br
.nr wg 1v
.ie \n(.h=\n(vk .nr wg -\n(vhu
.el .nr vh 0
.if \n(wg>0 \{\
.sp \n(wgu
.nr vh +\n(wgu \}
.nr vk \n(.h
.ti -\n(Inn
\&obj	\c
Pascal object file
.br
.nr wg 0v
.ie \n(.h=\n(vk .nr wg -\n(vhu
.el .nr vh 0
.if \n(wg>0 \{\
.sp \n(wgu
.nr vh +\n(wgu \}
.nr vk \n(.h
.ti -\n(Inn
\&\&.pdxinit	\c
\fIPdx\fP initialization file
.in -\n(Inn
.br
.nr wg 1v
.ie \n(.h=\n(vk .nr wg -\n(vhu
.el .nr vh 0
.if \n(wg>0 \{\
.sp \n(wgu
.nr vh +\n(wgu \}
.nr vk \n(.h
.SH SEE ALSO
pi(1), px(1)
.br
\fIAn Introduction to Pdx\fP
.SH BUGS
\fIPdx\fP does not understand sets,
and provides no information about files.
.sp 1
The \fIwhatis\fP command doesn't quite work for variant records.
.sp 1
Bad things will happen if a procedure invoked with
the \fBcall\fP command does a non-local goto.
.sp 1
The commands \fBstep\fP and \fBnext\fP should be able to take a \fIcount\fP
that specifies how many lines to execute.
.sp 1
There should be commands \fBstepi\fP and \fBnexti\fP that correspond
to \fBstep\fP and \fBnext\fP but work at the instruction level.
.sp 1
There should be a way to get an address associated with
a line number, procedure or function, and variable.
.sp 1
Most of the command names are too long.
.sp 1
The alias facility is quite weak.
.sp 1
A \fIcsh\fP-like history capability would improve the situation.