A tclcmd allows Tcl commands to be executed by a simple x << Tcl command syntax. The commands can be stacked, or accumulated. Each time a linefeed is obtained, the command is evaluated.

For example:

tclcmd cmd;

cmd << "set a 1\n puts stdout $a";
cmd << "for {set i 0} {$i < 10} {incr i}"
cmd << "{set a [expr $a+$i]; puts stdout $a}\n";

The behaviour of this command is slightly different from the usual stream classes (but identical to eco_strstream from which it is derived, as a space is automatically inserted between arguments of a <<. This means that arguments can be easily given - eg

cmd << "plot" << 1.2 << 3.4 << "\n";
will perform the command plot 1.2 3.4. In order to build up a symbol from multiple arguments, use the append operator. So
(cmd << "plot"|3) << "\n";
executes the command plot3.