if(n) Tcl Built-In Commands if(n)_________________________________________________________________NAMEif - Execute scripts conditionally
SYNOPSISif expr1 ?then? body1 elseif expr2 ?then? body2 elseif ...
?else? ?bodyN?
_________________________________________________________________DESCRIPTION
The if command evaluates expr1 as an expression (in the
same way that expr evaluates its argument). The value of
the expression must be a boolean (a numeric value, where 0
is false and anything is true, or a string value such as
true or yes for true and false or no for false); if it is
true then body1 is executed by passing it to the Tcl
interpreter. Otherwise expr2 is evaluated as an expres-
sion and if it is true then body2 is executed, and so on.
If none of the expressions evaluates to true then bodyN is
executed. The then and else arguments are optional
``noise words'' to make the command easier to read. There
may be any number of elseif clauses, including zero.
BodyN may also be omitted as long as else is omitted too.
The return value from the command is the result of the
body script that was executed, or an empty string if none
of the expressions was non-zero and there was no bodyN.
KEYWORDS
boolean, conditional, else, false, if, true
Tcl 1