NAME¶
console - Control the console on systems without a real console
SYNOPSIS¶
console subcommand ?
arg ...?
DESCRIPTION¶
The console window is a replacement for a real console to allow input and output
on the standard I/O channels on platforms that do not have a real console. It
is implemented as a separate interpreter with the Tk toolkit loaded, and
control over this interpreter is given through the
console command. The
behaviour of the console window is defined mainly through the contents of the
console.tcl file in the Tk library. Except for TkAqua, this command is
not available when Tk is loaded into a tclsh interpreter with “
package require Tk”, as a conventional terminal is expected to
be present in that case. In TkAqua, this command is ony available when stdin
is
/dev/null (as is the case e.g. when the application embedding Tk is
started from the Mac OS X Finder).
- console eval script
- Evaluate the script argument as a Tcl script in the console
interpreter. The normal interpreter is accessed through the
consoleinterp command in the console interpreter.
- console hide
- Hide the console window from view. Precisely equivalent to withdrawing the
. window in the console interpreter.
- console show
- Display the console window. Precisely equivalent to deiconifying the
. window in the console interpreter.
- console title ?string?
- Query or modify the title of the console window. If string is not
specified, queries the title of the console window, and sets the title of
the console window to string otherwise. Precisely equivalent to
using the wm title command in the console interpreter.
ACCESS TO THE MAIN INTERPRETER¶
The
consoleinterp command in the console interpreter allows scripts to be
evaluated in the main interpreter. It supports two subcommands:
eval
and
record.
- consoleinterp eval script
- Evaluates script as a Tcl script at the global level in the main
interpreter.
- consoleinterp record script
- Records and evaluates script as a Tcl script at the global level in
the main interpreter as if script had been typed in at the
console.
ADDITIONAL TRAP CALLS¶
There are several additional commands in the console interpreter that are called
in response to activity in the main interpreter.
These are documented here
for completeness only; they form part of the internal implementation of
the console and are likely to change or be modified without
warning.
Output to the console from the main interpreter via the stdout and stderr
channels is handled by invoking the
tk::ConsoleOutput command in the
console interpreter with two arguments. The first argument is the name of the
channel being written to, and the second argument is the string being written
to the channel (after encoding and end-of-line translation processing has been
performed.)
When the
. window of the main interpreter is destroyed, the
tk::ConsoleExit command in the console interpreter is called (assuming
the console interpreter has not already been deleted itself, that is.)
DEFAULT BINDINGS¶
The default script creates a console window (implemented using a text widget)
that has the following behaviour:
- [1]
- Pressing the tab key inserts a TAB character (as defined by the Tcl \t
escape.)
- [2]
- Pressing the return key causes the current line (if complete by the rules
of info complete) to be passed to the main interpreter for
evaluation.
- [3]
- Pressing the delete key deletes the selected text (if any text is
selected) or the character to the right of the cursor (if not at the end
of the line.)
- [4]
- Pressing the backspace key deletes the selected text (if any text is
selected) or the character to the left of the cursor (of not at the start
of the line.)
- [5]
- Pressing either Control+A or the home key causes the cursor to go to the
start of the line (but after the prompt, if a prompt is present on the
line.)
- [6]
- Pressing either Control+E or the end key causes the cursor to go to the
end of the line.
- [7]
- Pressing either Control+P or the up key causes the previous entry in the
command history to be selected.
- [8]
- Pressing either Control+N or the down key causes the next entry in the
command history to be selected.
- [9]
- Pressing either Control+B or the left key causes the cursor to move one
character backward as long as the cursor is not at the prompt.
- [10]
- Pressing either Control+F or the right key causes the cursor to move one
character forward.
- [11]
- Pressing F9 rebuilds the console window by destroying all its children and
reloading the Tcl script that defined the console's behaviour.
Most other behaviour is the same as a conventional text widget except for the
way that the
<<Cut>> event is handled identically to the
<<Copy>> event.
EXAMPLE¶
Not all platforms have the
console command, so debugging code often has
the following code fragment in it so output produced by
puts can be
seen while during development:
SEE ALSO¶
destroy(3tk), fconfigure(3tcl), history(3tcl), interp(3tcl), puts(3tcl),
text(3tk), wm(3tk)
KEYWORDS¶
console, interpreter, window, interactive, output channels