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Units and Functions
Units are groupings of functions and variables appearing in .mez
files. They can be thought of as modules or namespaces. A Helium app must have at least one unit. The unit
keyword must be followed by a unique unit name. A unit must have at least one function.
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unit MyUnit;
// Other code follows
string myVar;
int factorial(int x) {
if(x == 0 || x == 1) {
return 1;
} else if (x > 1) {
return factorial(x - 1);
}
return 0;
} |
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Objects, enums and validators are global, so they can optionally be in a separate source code file without a unit. |
Mez File Comments
Two types of comments are supported: single line comments and multi-line comments:
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// date tstamp = System.now();
// decimal rand = System.random(); |
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/* date tstamp = System.now();
decimal rand = System.random(); */ |
Variable and Function Scope
Suppose a unit MyUnit
has a unit variable named myVar
and a function named factorial
. Both have global scope and can be accessed by any function in this or other units, e.g. from TestUnit
in the example below. The only time a variable or custom object in the Helium DSL is not globally scoped is when it is declared inside a function and thus scoped to the function alone. To refer to a unit’s member functions or variables from another unit, you have to use the scope operator (the colon).
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unit TestUnit;
void test() {
MyUnit:myVar = "New string value!";
int f = MyUnit:factorial(5);
} |
Note: Unit variables cannot be in line initialized when they are declared. The following code will not compile:
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unit MyUnit;
string myVar = "some value"; // this is not a legal statement |
Additional Mentions and References
- Sections Adding a Presenter and Referencing Unit Variables and Functions in Lesson 1 of the Tutorial.
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units | functions | comments | global scope |