Next: Break, Previous: Assert, Up: Statements
To set the value of an already defined variable to a different value, use a statement of the following form:
$var := expr;
The expression expr is evaluated and the result is assigned to the variable $var. The variable must have already been defined.
You can assign the elements of a list value to multiple variables at once:
<$var1, $var2, ... > := expr;
The first, second, ... element of expr, which must be a list, is assigned to variable $var1, $var2, ... respectively. Any of these variables may be followed by a path. The number of variables must match the length of the list value.
You can optionally specify a path behind the variable that is to be set by an assignment:
$var.part1.part2 := value;
In this case, only the value of $var.
part1.
part2
will be set to value; the remainder of the variable $var
will be unchanged. Each part must be an expression that evaluates
to a symbol, a number or a list of symbols and numbers.
You can also use one of four other assignment operators instead of the operator
`:=': The statement $var :=+
value;
is a
shorthand for $var :=
$var +
value;
. The
same holds for the assignment operators `:=-', `:=*', and
`:=/'. Here, $var may be followed by a path again.