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.
Unit Example
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;
}
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:
Single Line Comments Example
// date tstamp = System.now();
// decimal rand = System.random();
Multi-line Comments Example
/* 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. 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).
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:
unit MyUnit;
string myVar = "some value"; // this is not a legal statement
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