Tcl Source Code

.TP
\fBinfo body \fIprocname\fR
.
Returns the body of procedure \fIprocname\fR.  \fIProcname\fR must be
the name of a Tcl command procedure.
.TP
\fBinfo class\fI subcommand class\fR ?\fIarg ...\fR

.
Returns information about the class, \fIclass\fR. The \fIsubcommand\fRs are
described in \fBCLASS INTROSPECTION\fR below.

.TP
\fBinfo cmdcount\fR
.
Returns a count of the total number of commands that have been invoked
in this interpreter.
.TP
\fBinfo commands \fR?\fIpattern\fR?

If the command does not appear to be complete then 0 is returned.
This command is typically used in line-oriented input environments
to allow users to type in commands that span multiple lines;  if the
command is not complete, the script can delay evaluating it until additional
lines have been typed to complete the command.
.TP
\fBinfo coroutine\fR

.
Returns the name of the currently executing \fBcoroutine\fR, or the empty
string if either no coroutine is currently executing, or the current coroutine
has been deleted (but has not yet returned or yielded since deletion).

.TP
\fBinfo default \fIprocname arg varname\fR
.
\fIProcname\fR must be the name of a Tcl command procedure and \fIarg\fR
must be the name of an argument to that procedure.  If \fIarg\fR
does not have a default value then the command returns \fB0\fR.
Otherwise it returns \fB1\fR and places the default value of \fIarg\fR
into variable \fIvarname\fR.
.TP
\fBinfo errorstack \fR?\fIinterp\fR?

.
Returns, in a form that is programmatically easy to parse, the function names
and arguments at each level from the call stack of the last error in the given
\fIinterp\fR, or in the current one if not specified.
.RS
.PP
This form is an even-sized list alternating tokens and parameters. Tokens are
currently either \fBCALL\fR, \fBUP\fR, or \fBINNER\fR, but other values may be

granularity.
.PP
This information is also present in the \fB\-errorstack\fR entry of the
options dictionary returned by 3-argument \fBcatch\fR; \fBinfo errorstack\fR
is a convenient way of retrieving it for uncaught errors at top-level in an
interactive \fBtclsh\fR.
.RE

.TP
\fBinfo exists \fIvarName\fR
.
Returns \fB1\fR if the variable named \fIvarName\fR exists in the
current context (either as a global or local variable) and has been
defined by being given a value, returns \fB0\fR otherwise.
.TP

\fBinfo nameofexecutable\fR
.
Returns the full path name of the binary file from which the application
was invoked.  If Tcl was unable to identify the file, then an empty
string is returned.
.TP
\fBinfo object\fI subcommand object\fR ?\fIarg ...\fR

.
Returns information about the object, \fIobject\fR. The \fIsubcommand\fRs are
described in \fBOBJECT INTROSPECTION\fR below.

.TP
\fBinfo patchlevel\fR
.
Returns the value of the global variable \fBtcl_patchLevel\fR, which holds
the exact version of the Tcl library by default.
.TP
\fBinfo procs \fR?\fIpattern\fR?

has each matching namespace variable qualified with the name
of its namespace.
Note that a currently-visible variable may not yet
.QW exist
if it has not
been set (e.g. a variable declared but not set by \fBvariable\fR).
.SS "CLASS INTROSPECTION"

.PP
The following \fIsubcommand\fR values are supported by \fBinfo class\fR:

.TP
\fBinfo class call\fI class method\fR

.
Returns a description of the method implementations that are used to provide a
stereotypical instance of \fIclass\fR's implementation of \fImethod\fR
(stereotypical instances being objects instantiated by a class without having
any object-specific definitions added). This consists of a list of lists of
four elements, where each sublist consists of a word that describes the
general type of method implementation (being one of \fBmethod\fR for an
ordinary method, \fBfilter\fR for an applied filter, and \fBunknown\fR for a
method that is invoked as part of unknown method handling), a word giving the
name of the particular method invoked (which is always the same as
\fImethod\fR for the \fBmethod\fR type, and
.QW \fBunknown\fR
for the \fBunknown\fR type), a word giving the fully qualified name of the
class that defined the method, and a word describing the type of method
implementation (see \fBinfo class methodtype\fR).
.RS
.PP
Note that there is no inspection of whether the method implementations
actually use \fBnext\fR to transfer control along the call chain.
.RE

.TP
\fBinfo class constructor\fI class\fR

.
This subcommand returns a description of the definition of the constructor of
class \fIclass\fR. The definition is described as a two element list; the first
element is the list of arguments to the constructor in a form suitable for
passing to another call to \fBproc\fR or a method definition, and the second
element is the body of the constructor. If no constructor is present, this
returns the empty list.

.TP
\fBinfo class definition\fI class method\fR

.
This subcommand returns a description of the definition of the method named
\fImethod\fR of class \fIclass\fR. The definition is described as a two element
list; the first element is the list of arguments to the method in a form
suitable for passing to another call to \fBproc\fR or a method definition, and
the second element is the body of the method.

.TP
\fBinfo class destructor\fI class\fR

.
This subcommand returns the body of the destructor of class \fIclass\fR. If no
destructor is present, this returns the empty string.

.TP
\fBinfo class filters\fI class\fR

.
This subcommand returns the list of filter methods set on the class.

.TP
\fBinfo class forward\fI class method\fR

.
This subcommand returns the argument list for the method forwarding called
\fImethod\fR that is set on the class called \fIclass\fR.

.TP
\fBinfo class instances\fI class\fR ?\fIpattern\fR?

.
This subcommand returns a list of instances of class \fIclass\fR. If the
optional \fIpattern\fR argument is present, it constrains the list of returned
instances to those that match it according to the rules of \fBstring match\fR.

.TP
\fBinfo class methods\fI class\fR ?\fIoptions...\fR?

.
This subcommand returns a list of all public (i.e. exported) methods of the
class called \fIclass\fR. Any of the following \fIoption\fRs may be
specified, controlling exactly which method names are returned:
.RS

.TP
\fB\-all\fR
.
If the \fB\-all\fR flag is given,
.VS TIP500
and the \fB\-scope\fR flag is not given,
.VE TIP500
the list of methods will include those
methods defined not just by the class, but also by the class's superclasses
and mixins.

.TP
\fB\-private\fR
.
If the \fB\-private\fR flag is given,
.VS TIP500
and the \fB\-scope\fR flag is not given,
.VE TIP500
the list of methods will also include
the non-exported methods of the class (and superclasses and
mixins, if \fB\-all\fR is also given).
.VS TIP500
Note that this naming is an unfortunate clash with true private methods; this
option name is retained for backward compatibility.
.VE TIP500
.TP
\fB\-scope\fI scope\fR
.VS TIP500
Returns a list of all methods on \fIclass\fR that have the given visibility
\fIscope\fR.  When this option is supplied, both the \fB\-all\fR and
\fB\-private\fR options are ignored. The valid values for \fIscope\fR are:
.RS
.IP \fBpublic\fR 3
Only methods with \fIpublic\fR scope (i.e., callable from anywhere by any instance
of this class) are to be returned.
.IP \fBunexported\fR 3
Only methods with \fIunexported\fR scope (i.e., only callable via \fBmy\fR) are to
be returned.
.IP \fBprivate\fR 3
Only methods with \fIprivate\fR scope (i.e., only callable from within this class's
methods) are to be returned.
.RE
.VE TIP500
.RE
.TP
\fBinfo class methodtype\fI class method\fR

.
This subcommand returns a description of the type of implementation used for
the method named \fImethod\fR of class \fIclass\fR. When the result is
\fBmethod\fR, further information can be discovered with \fBinfo class
definition\fR, and when the result is \fBforward\fR, further information can
be discovered with \fBinfo class forward\fR.

.TP
\fBinfo class mixins\fI class\fR

.
This subcommand returns a list of all classes that have been mixed into the
class named \fIclass\fR.

.TP
\fBinfo class subclasses\fI class\fR ?\fIpattern\fR?

.
This subcommand returns a list of direct subclasses of class \fIclass\fR. If
the optional \fIpattern\fR argument is present, it constrains the list of
returned classes to those that match it according to the rules of
\fBstring match\fR.

.TP
\fBinfo class superclasses\fI class\fR

.
This subcommand returns a list of direct superclasses of class \fIclass\fR in
inheritance precedence order.

.TP
\fBinfo class variables\fI class\fR ?\fB\-private\fR?

.
This subcommand returns a list of all variables that have been declared for
the class named \fIclass\fR (i.e. that are automatically present in the
class's methods, constructor and destructor).
.VS TIP500
If the \fB\-private\fR option is specified, this lists the private variables
declared instead.
.VE TIP500
.SS "OBJECT INTROSPECTION"
.PP
The following \fIsubcommand\fR values are supported by \fBinfo object\fR:

.TP
\fBinfo object call\fI object method\fR

.
Returns a description of the method implementations that are used to provide
\fIobject\fR's implementation of \fImethod\fR.  This consists of a list of
lists of four elements, where each sublist consists of a word that describes
the general type of method implementation (being one of \fBmethod\fR for an
ordinary method, \fBfilter\fR for an applied filter, and \fBunknown\fR for a
method that is invoked as part of unknown method handling), a word giving the
name of the particular method invoked (which is always the same as
\fImethod\fR for the \fBmethod\fR type, and
.QW \fBunknown\fR
for the \fBunknown\fR type), a word giving what defined the method (the fully
qualified name of the class, or the literal string \fBobject\fR if the method
implementation is on an instance), and a word describing the type of method
implementation (see \fBinfo object methodtype\fR).
.RS
.PP
Note that there is no inspection of whether the method implementations
actually use \fBnext\fR to transfer control along the call chain.
.RE

.TP
\fBinfo object class\fI object\fR ?\fIclassName\fR?

.
If \fIclassName\fR is unspecified, this subcommand returns class of the
\fIobject\fR object. If \fIclassName\fR is present, this subcommand returns a
boolean value indicating whether the \fIobject\fR is of that class.

.TP
\fBinfo object creationid\fI object\fR
.VS TIP500
Returns the unique creation identifier for the \fIobject\fR object. This
creation identifier is unique to the object (within a Tcl interpreter) and
cannot be controlled at object creation time or altered afterwards.
.RS
.PP
\fIImplementation note:\fR the creation identifier is used to generate unique
identifiers associated with the object, especially for private variables.
.RE
.VE TIP500
.TP
\fBinfo object definition\fI object method\fR

.
This subcommand returns a description of the definition of the method named
\fImethod\fR of object \fIobject\fR. The definition is described as a two
element list; the first element is the list of arguments to the method in a
form suitable for passing to another call to \fBproc\fR or a method definition,
and the second element is the body of the method.

.TP
\fBinfo object filters\fI object\fR

.
This subcommand returns the list of filter methods set on the object.

.TP
\fBinfo object forward\fI object method\fR

.
This subcommand returns the argument list for the method forwarding called
\fImethod\fR that is set on the object called \fIobject\fR.

.TP
\fBinfo object isa\fI category object\fR ?\fIarg\fR?

.
This subcommand tests whether an object belongs to a particular category,
returning a boolean value that indicates whether the \fIobject\fR argument
meets the criteria for the category. The supported categories are:

.RS
.TP
\fBinfo object isa class\fI object\fR

.
This returns whether \fIobject\fR is a class (i.e. an instance of
\fBoo::class\fR or one of its subclasses).

.TP
\fBinfo object isa metaclass\fI object\fR

.
This returns whether \fIobject\fR is a class that can manufacture classes
(i.e. is \fBoo::class\fR or a subclass of it).

.TP
\fBinfo object isa mixin\fI object class\fR

.
This returns whether \fIclass\fR is directly mixed into \fIobject\fR.

.TP
\fBinfo object isa object\fI object\fR

.
This returns whether \fIobject\fR really is an object.

.TP
\fBinfo object isa typeof\fI object class\fR

.
This returns whether \fIclass\fR is the type of \fIobject\fR (i.e. whether
\fIobject\fR is an instance of \fIclass\fR or one of its subclasses, whether
direct or indirect).
.RE

.TP
\fBinfo object methods\fI object\fR ?\fIoption...\fR?

.
This subcommand returns a list of all public (i.e. exported) methods of the
object called \fIobject\fR. Any of the following \fIoption\fRs may be
specified, controlling exactly which method names are returned:
.RS

.TP
\fB\-all\fR
.
If the \fB\-all\fR flag is given,
.VS TIP500
and the \fB\-scope\fR flag is not given,
.VE TIP500
the list of methods will include those
methods defined not just by the object, but also by the object's class and
mixins, plus the superclasses of those classes.

.TP
\fB\-private\fR
.
If the \fB\-private\fR flag is given,
.VS TIP500
and the \fB\-scope\fR flag is not given,
.VE TIP500
the list of methods will also include
the non-exported methods of the object (and classes, if
\fB\-all\fR is also given).
.VS TIP500
Note that this naming is an unfortunate clash with true private methods; this
option name is retained for backward compatibility.
.VE TIP500
.TP
\fB\-scope\fI scope\fR
.VS TIP500
Returns a list of all methods on \fIobject\fR that have the given visibility
\fIscope\fR.  When this option is supplied, both the \fB\-all\fR and
\fB\-private\fR options are ignored. The valid values for \fIscope\fR are:
.RS
.IP \fBpublic\fR 3
Only methods with \fIpublic\fR scope (i.e., callable from anywhere) are to be
returned.
.IP \fBunexported\fR 3
Only methods with \fIunexported\fR scope (i.e., only callable via \fBmy\fR) are to
be returned.
.IP \fBprivate\fR 3
Only methods with \fIprivate\fR scope (i.e., only callable from within this object's
instance methods) are to be returned.
.RE
.VE TIP500
.RE
.TP
\fBinfo object methodtype\fI object method\fR

.
This subcommand returns a description of the type of implementation used for
the method named \fImethod\fR of object \fIobject\fR. When the result is
\fBmethod\fR, further information can be discovered with \fBinfo object
definition\fR, and when the result is \fBforward\fR, further information can
be discovered with \fBinfo object forward\fR.

.TP
\fBinfo object mixins\fI object\fR

.
This subcommand returns a list of all classes that have been mixed into the
object named \fIobject\fR.

.TP
\fBinfo object namespace\fI object\fR

.
This subcommand returns the name of the internal namespace of the object named
\fIobject\fR.

.TP
\fBinfo object variables\fI object\fRR ?\fB\-private\fR?

.
This subcommand returns a list of all variables that have been declared for
the object named \fIobject\fR (i.e. that are automatically present in the
object's methods).
.VS TIP500
If the \fB\-private\fR option is specified, this lists the private variables
declared instead.
.VE TIP500
.TP
\fBinfo object vars\fI object\fR ?\fIpattern\fR?

.
This subcommand returns a list of all variables in the private namespace of
the object named \fIobject\fR. If the optional \fIpattern\fR argument is
given, it is a filter (in the syntax of a \fBstring match\fR glob pattern)
that constrains the list of variables returned. Note that this is different
from the list returned by \fBinfo object variables\fR; that can include
variables that are currently unset, whereas this can include variables that
are not automatically included by any of \fIobject\fR's methods (or those of
its class, superclasses or mixins).

.SH EXAMPLES
.PP
This command prints out a procedure suitable for saving in a Tcl
script:
.PP
.CS
proc printProc {procName} {

            lappend formals [list $var]
        }
    }
    puts [lappend result $formals [\fBinfo body\fR $procName]]
}
.CE
.SS "EXAMPLES WITH OBJECTS"

.PP
Every object necessarily knows what its class is; this information is
trivially extractable through introspection:
.PP
.CS
oo::class create c
c create o

            error "no definition for $method"
        }
    }
    # Assume no forwards
    return [\fBinfo class definition\fR $cls $method]
}
.CE

.SH "SEE ALSO"

global(n), oo::class(n), oo::define(n), oo::object(n), proc(n), self(n),

tcl_library(n), tcl_patchLevel(n), tcl_version(n)
.SH KEYWORDS
command, information, interpreter, introspection, level, namespace,



object, procedure, variable
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