Variables

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A variable is a memory space defined in the program. There are several types of variables in the Hugo Programming languages. Public variables are defined through the declarative command global. Variables used only by a routine are defined through the declarative command local. Variables which are attached to an object are either declared as attributes, which can hold only a true/false value, or as properties, which can hold any value.

Contents


A variable is a named location in the computer's memory. Each variable is used to hold a piece of information that your game may need to refer to in various places of the code and where the data stored in that variable might not be the same at the beginning of the game as in the middle, or the end (i.e. the information varies. If you have a piece of information that will never change, you're better off using a constant.

A variable is defined by an identifier, which is the name of that variable and how it is referenced by the program. An identifier can contain up to 32 alpha-numeric characters. The only punctuation character allowed in an identifier is the underscore ("_"). The name of a variable also cannot be any one of Hugo's predefined words (like property, routine, and function names). If a variable is global to the program (as opposed to a local defined in a routine) it must not have the same name as any other global, attribute, or object.

Sample name Valid? Why or Why not
suitcase
suitcase2
Yes Only letters for the first character; letters, numbers or an underscore for subsequent characters; less than 32 characters
drug list
A wine list
No Names can't have spaces in them
apple.pie.slice No The name contains periods. The only legal punctuation is the underscore
apple_pie_slice
I
Yes Perfectly legal name, fits all the rules
apple.pieslice No The name would be confusing as it would be confused with a variable named apple with a property called "pieslice". Would be legal to use, however, for an object named apple if there is a property named pieslice.
ReallyReallyLongNameForAVariable Yes Within the 32 character limit (just)


Global Variables

Main article: global

A global variable is defined through the following specification:

global <variable_name> [= optional initial value]

if a value is not specified, it is zero.

A global variable is one that is available anywhere in the program at any time. It must be unique to any other global variable, property or object.

Format: global identifier [= optional value]

global xyzzy
global favorite_color = "blue"

If a global is not given a value, it defaults to 0.

Enumeration

Like constants, you can use the enumerate command to define your global variables with initial values. You just need to use the globals attribute:

enumerate globals
{
<global1>, <global2>,...
}

global1 = 0, global2 = 1, etc. (Check out the Constants page for more information on enumeration)

Local Variables

Main article: locals

A local variable is a variable that can only be accessed within the routine that it is defined in. Other routines do not have access to another routine's local variable. A local variable is defined in a very similar manner to a global.

A local variable is defined through the following specification:

local <variable_name> [= optional initial value]

if a value is not specified, it is zero.

Lets say you need a routine that will count down from any number that is passed to it, it might be defined like this:

    routine CountDown(count_from)
    {
        local count
 
        print "The countdown has begun!\n"
 
        for (count = count_from; count > 1; count = count - 1)
            print number count; " seconds remain."
 
        "Boom goes the dynamite."
 
    }
 
    routine HowManyCoins
    {
        local count
 
        for count in mywallet
            { 
            count = count + 1
            }
 
        print "There are "; number count; " coins in my wallet."
    }

In this sample, we have two routines, each of which defines a local variable named count. Because they are defined in two different routines, they can have the same name. The count variable in the CountDown routine will never be confused with the count variable in the HowManyCoins routine.

Do's and Don'ts

If you create a class, be sure it's not the same as a prior variable you've used. The compiler will allow you to use a class name as a variable, and if you do, the run-time will crash. For example, if you used the following:

global Merchandise
 
 
[ and in several places you had the following code: ]
 
    Merchandise++

If later, you decided to change that variable to Merchandise_Count, and then created a class called Merchandise, if you forget to change all references of Merchandise++ to Merchandise_Count++ (or any other arithmetic reference), once you add one to the class name, the run-time will crash the game.

See Also: attributes, identifier, properties

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