Built-In Commands - eval manual page

### NAME

eval - Evaluate a Tcl script

### SYNOPSIS

eval arg ?arg ...?

### DESCRIPTION

Eval takes one or more arguments, which together comprise a Tcl script containing one or more commands. Eval concatenates all its arguments in the same fashion as the concat command, passes the concatenated string to the Tcl interpreter recursively, and returns the result of that evaluation (or any error generated by it). Note that the list command quotes sequences of words in such a way that they are not further expanded by the eval command.

### EXAMPLE

This procedure acts in a way that is analogous to the lappend command, except it inserts the argument values at the start of the list in the variable:

    proc lprepend {varName args} {
       upvar 1 $varName var
       # Ensure that the variable exists and contains a list
       lappend var
       # Now we insert all the arguments in one go
       set var [eval [list linsert $var 0] $args]
    }

### KEYWORDS

concatenate, evaluate, script

### SEE ALSO

catch, concat, error, list, subst, tclvars

    Copyright © 1993 The Regents of the University of California.
    Copyright © 1994-1996 Sun Microsystems, Inc.
    Copyright © 1995-1997 Roger E. Critchlow Jr.