var is used to:
- start section of variable declarations, and
- declare a formal parameter as penetrating mutable.
Variable declaration section
In a block the word
var starts a section of one or more variable declarations.
var age: integer;
var firstName, lastName, address: string;
var prior a formal parameter declaration indicates that this parameter is variable, that means assigning values to it will affect the named parameter at the call site.
procedure censor(var xxx: longWord); begin if (xxx = $4655434B) or (xxx = $6675636B) then begin xxx := $2A2A2A2A; end; end;
procedure censor the value of the variable that was supplied at the call site (i. e. where the procedure was called) will (possibly) have changed, too.