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eval (n)
eval(n) Tcl Built-In Commands eval(n)
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NAME
eval - Evaluate a Tcl script
SYNOPSIS
eval arg ?arg ...?
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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 fur-
ther 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(n), concat(n), error(n), list(n), subst(n), tclvars(n)
Tcl eval(n)
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