The Trace Facility
Axiom contains some powerful commands to help with testing and
debugging library modules written in Spad and also the Axiom system
itself. The most important of these commands is )trace.
This command is used to trace the execution of functions that make
up the Axiom system, functions defined by users, and functions from
the system library. Almost all options are available for each type
of function but exceptions will be noted below.
To list all functions, constructors, domains and packages that are
traced, simply issue:
)trace
To untrace everything that is traced, issue:
)trace )off
When a function is traced, the default system action is to display
the arguments to the function and the return value when the function
is exited. Other information can be displayed or collected when a
function is traced and this is controlled by the various options.
If a domain or package is traced, the default action is to trace all
functions exported. Individual interpreter, lisp or boot functions
can be traced by listing their names after )trace. Any options that
are present must follow the functions to be traced. For example:
)trace f
traces the function f. To untrace f, issue:
)trace f )off
Note that if a function name contains a special character, it will
be necessary to escape the character with an underscore:
)trace _/D_,1
To trace all domains or packages that are or will be created from a
particular constructor, give the constructor name or abbreviation
after ')trace':
)trace MATRIX
)trace List Integer
The first command traces all domains currently instantiated with
Matrix. If additional domains are instantiated with this constructor
(for example, if you have used Matrix(Integer) and Matrix(Float)),
they will be automatically traced. The second command traces
List(Integer).
The following are the general options for the )trace command.
)break after- causes a Common Lisp break loop to be entered after
exiting the traced function.
)break before- causes a Common Lisp break loop to be entered before
entering the traced function.
)break- is the same as )break before.
)count- causes the system to keep a count of the number of times the
traced function is entered.
The total can be displayed with:
)trace )stats
and cleared with:
)trace )stats reset
)count n- causes information about the traced function to be displayed
for the first n executions. After the n-th execution, the function is
untraced.
)depth n- causes trace information to be shown for only n levels of
recursion of the traced function.
The command:
)trace fib )depth 10
will cause the display of only 10 levels of trace information for the
recursive execution of a user function fib.
)math causes- the function arguments and return value to be displayed
in the Axiom monospace two-dimensional math format.
)nonquietly- causes the display of additional messages when a function
is traced.
)nt- This suppresses all normal trace information. This option is useful
if the
)count or )timer options are used and you are interested in the
statistics but not the function calling information.
)off- causes untracing of all or specific functions. Without an argument,
all functions, constructors, domains and packages are untraced. Otherwise,
the given functions and other objects are untraced.
To immediately retrace the untraced functions, issue:
)trace )restore
)only listOfDataToDisplay- causes only specific trace information to be
shown.
)restore- causes the last untraced functions to be retraced. If
additional options are present, they are added to those previously in
effect.
)stats- causes the display of statistics collected by the use of the
)count and )timer options.
)stats reset- resets to 0 the statistics collected by the use of the
)count and )timer options.
)timer- causes the system to keep a count of execution times for the
traced function. The total can be displayed with
)trace )stats and
cleared with )trace )stats reset.
)varbreak var1 ... varN- causes a Common Lisp break loop to be
entered after the assignment to any of the listed variables in the
traced function.
)vars- causes the display of the value of any variable after it is
assigned in the traced function. Note that library code must have been
compiled using the
)vartrace option in order to support this option.
)vars var1 ... varN- causes the display of the value of any of
the specified variables after they are assigned in the traced function.
Note that library code must have been compiled using the
)vartrace
option in order to support this option.
)within executingFunction- causes the display of trace information
only if the traced function is called when the given executingFunction
is running.
The following are the options for tracing constructors, domains and
packages.
)local op1 ... opN- causes local functions of the constructor to
be traced. Note that to untrace an individual local function, you must
use the fully qualified internal name, using the escape character before
the semicolon. For example:
)trace FRAC )local
)trace FRAC_;cancelGcd )off
)ops op1 ... opN- By default, all operations from a domain or package
are traced when the domain or package is traced. This option allows you
to specify that only particular operations should be traced.
The command:
)trace Integer )ops min max _+ _-
traces four operations from the domain Integer. Since + and - are special
characters, it is necessary to escape them with an underscore.
Also See: )boot, )lisp , and )ltrace. Please refer to the
Axiom Book, section "Axiom System Commands"
for more detailed information.