Reference: Parameter

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A Parameter is a variable declaration in a function definition that specifies what values the function can receive when called. Each parameter must declare its Data Type and name, creating a local variable that exists only within the function's scope.

Parameter Structure

Parameters are declared inside the Group delimiters following a function name. Each parameter consists of:

A Data Type
A parameter name (following variable naming rules)

Single Parameter

A function with one parameter receives a single value when called.

Example: Single Integer Parameter

FUNCTION square ( INT n )
    NEW INT result = n * n
    RETURN result
END FUNCTION

NEW INT value = square ( 5 )
PRINTLN value // Displays "25"

Example: Single String Parameter

FUNCTION greet ( STR name )
    PRINTLN "Hello, " .. name .. "!"
END FUNCTION

greet ( "Alice" )
// Displays "Hello, Alice!"

Example: Single Float Parameter

FUNCTION double ( FLOAT value )
    NEW FLOAT result = value * 2.0
    RETURN result
END FUNCTION

NEW FLOAT doubled = double ( 3.5 )
PRINTLN doubled // Displays "7.0"

Example: Single Boolean Parameter

FUNCTION checkStatus ( BOOL isActive )
    IF isActive == TRUE
        PRINTLN "Status: Active"
    ELSE
        PRINTLN "Status: Inactive"
    END IF
END FUNCTION

checkStatus ( TRUE )
// Displays "Status: Active"

Multiple Parameters

When a function needs multiple values, parameters are separated by the Divider delimiter (comma). Each parameter must have its own data type declaration.

Example: Two Parameters

FUNCTION add ( INT a , INT b )
    NEW INT sum = a + b
    RETURN sum
END FUNCTION

NEW INT result = add ( 5 , 3 )
PRINTLN result // Displays "8"

Example: Three Parameters

FUNCTION calculateAverage ( FLOAT a , FLOAT b , FLOAT c )
    NEW FLOAT sum = a + b + c
    NEW FLOAT avg = sum / 3.0
    RETURN avg
END FUNCTION

NEW FLOAT average = calculateAverage ( 10.0 , 20.0 , 30.0 )
PRINTLN average // Displays "20.0"

Example: Four Parameters with Different Types

FUNCTION displayInfo ( STR name , INT age , FLOAT height , BOOL isStudent )
    PRINTLN "Name: " .. name
    PRINTLN "Age: " .. age
    PRINTLN "Height: " .. height
    PRINTLN "Student: " .. isStudent
END FUNCTION

displayInfo ( "Bob" , 25 , 5.9 , TRUE )

Example: Five Parameters

FUNCTION createRecord ( STR firstName , STR lastName , INT age , FLOAT salary , BOOL active )
    NEW STR fullName = firstName .. " " .. lastName
    PRINTLN "Employee: " .. fullName
    PRINTLN "Age: " .. age
    PRINTLN "Salary: $" .. salary
    PRINTLN "Active: " .. active
END FUNCTION

createRecord ( "John" , "Doe" , 30 , 50000.0 , TRUE )

No Parameters

Functions can be defined with no parameters, indicated by empty Group delimiters.

Example: Function with No Parameters

FUNCTION sayHello ( )
    PRINTLN "Hello, World!"
END FUNCTION

sayHello ( )
// Displays "Hello, World!"

Example: Returning a Value with No Parameters

FUNCTION getDefaultValue ( )
    RETURN 42
END FUNCTION

NEW INT value = getDefaultValue ( )
PRINTLN value // Displays "42"

Parameters vs Arguments

Parameters are the variable declarations in the function definition. Arguments are the actual values passed when calling the function.

Example: Parameters and Arguments

// Parameters: INT x and INT y (defined in function)
FUNCTION multiply ( INT x , INT y )
    RETURN x * y
END FUNCTION

// Arguments: 6 and 7 (passed to function)
NEW INT result = multiply ( 6 , 7 )
PRINTLN result // Displays "42"

Parameter Scope

Parameters are local variables that exist only within the function. They cannot be accessed outside the function.

Example: Parameter Scope

FUNCTION calculate ( INT value )
    NEW INT doubled = value * 2
    RETURN doubled
END FUNCTION

NEW INT result = calculate ( 10 )
PRINTLN result // Displays "20"
// PRINTLN value // Runtime error! value doesn't exist here

Example: Parameters Don't Affect External Variables

NEW INT original = 5

FUNCTION modifyValue ( INT num )
    SET num = num + 10
    PRINTLN "Inside function: " .. num
    RETURN num
END FUNCTION

NEW INT modified = modifyValue ( original )
PRINTLN "Original: " .. original // Displays "Original: 5"
PRINTLN "Modified: " .. modified // Displays "Modified: 15"

Parameter Order

Arguments are matched to parameters by position. The first argument is assigned to the first parameter, the second to the second, and so on.

Example: Order Matters

FUNCTION divide ( INT numerator , INT denominator )
    NEW INT result = numerator / denominator
    RETURN result
END FUNCTION

NEW INT answer1 = divide ( 10 , 2 )
PRINTLN answer1 // Displays "5" (10 / 2)

NEW INT answer2 = divide ( 2 , 10 )
PRINTLN answer2 // Displays "0" (2 / 10 = 0 in integer division)

Example: Descriptive Parameter Names

FUNCTION calculateDiscount ( FLOAT originalPrice , FLOAT discountPercent )
    NEW FLOAT discount = originalPrice * ( discountPercent / 100.0 )
    NEW FLOAT finalPrice = originalPrice - discount
    RETURN finalPrice
END FUNCTION

NEW FLOAT price = calculateDiscount ( 100.0 , 20.0 )
PRINTLN price // Displays "80.0"

Parameter Naming

Parameter names follow the same rules as variable names: they can contain letters (both uppercase and lowercase) and are case-sensitive.

Example: Case-Sensitive Parameters

FUNCTION example ( INT value , INT Value , INT VALUE )
    NEW INT sum = value + Value + VALUE
    RETURN sum
END FUNCTION

NEW INT total = example ( 1 , 2 , 3 )
PRINTLN total // Displays "6"

Using Parameters in Different Data Types

Example: Boolean Parameters

FUNCTION checkEligibility ( BOOL isAdult , BOOL hasLicense )
    IF isAdult && hasLicense
        RETURN TRUE
    ELSE
        RETURN FALSE
    END IF
END FUNCTION

NEW BOOL canDrive = checkEligibility ( TRUE , TRUE )
PRINTLN canDrive // Displays "TRUE"

Example: Integer Parameters

FUNCTION isInRange ( INT value , INT min , INT max )
    NEW BOOL inRange = ( value >= min ) && ( value <= max )
    RETURN inRange
END FUNCTION

IF isInRange ( 50 , 1 , 100 )
    PRINTLN "In range"
END IF
// Displays "In range"

Example: Float Parameters

FUNCTION calculateArea ( FLOAT width , FLOAT height )
    NEW FLOAT area = width * height
    RETURN area
END FUNCTION

NEW FLOAT roomArea = calculateArea ( 10.5 , 8.0 )
PRINTLN "Area: " .. roomArea // Displays "Area: 84.0"

Example: String Parameters

FUNCTION getFullName ( STR firstName , STR lastName )
    NEW STR fullName = firstName .. " " .. lastName
    RETURN fullName
END FUNCTION

NEW STR name = getFullName ( "John" , "Doe" )
PRINTLN name // Displays "John Doe"

Parameters in Complex Functions

Example: Parameters with Conditionals

FUNCTION getGrade ( INT score )
    NEW STR grade = ""
    IF score >= 90
        SET grade = "A"
    ELIF score >= 80
        SET grade = "B"
    ELIF score >= 70
        SET grade = "C"
    ELIF score >= 60
        SET grade = "D"
    ELSE
        SET grade = "F"
    END IF
    RETURN grade
END FUNCTION

NEW STR letterGrade = getGrade ( 85 )
PRINTLN letterGrade // Displays "B"

Example: Parameters with Loops

FUNCTION factorial ( INT n )
    NEW INT result = 1
    NEW INT i = 1
    WHILE i <= n
        SET result = result * i
        SET i = i + 1
    END WHILE
    RETURN result
END FUNCTION

NEW INT fact5 = factorial ( 5 )
PRINTLN "5! = " .. fact5 // Displays "5! = 120"

Practical Applications

Example: Temperature Conversion

FUNCTION celsiusToFahrenheit ( FLOAT celsius )
    NEW FLOAT fahrenheit = ( celsius * 9.0 / 5.0 ) + 32.0
    RETURN fahrenheit
END FUNCTION

NEW FLOAT tempF = celsiusToFahrenheit ( 25.0 )
PRINTLN tempF // Displays "77.0"

Example: Tax Calculator

FUNCTION calculateTax ( FLOAT amount , FLOAT rate )
    NEW FLOAT tax = amount * rate
    RETURN tax
END FUNCTION

FUNCTION getTotalWithTax ( FLOAT amount , FLOAT taxRate )
    NEW FLOAT tax = calculateTax ( amount , taxRate )
    NEW FLOAT total = amount + tax
    RETURN total
END FUNCTION

NEW FLOAT total = getTotalWithTax ( 100.0 , 0.08 )
PRINTLN "Total: $" .. total // Displays "Total: $108.0"

Example: String Formatter

FUNCTION formatMessage ( STR prefix , STR content , STR suffix )
    NEW STR message = prefix .. " " .. content .. " " .. suffix
    RETURN message
END FUNCTION

NEW STR output = formatMessage ( "[INFO]" , "Process completed" , "successfully" )
PRINTLN output // Displays "[INFO] Process completed successfully"

Important Notes

Each parameter must declare its Data Type.
Multiple parameters are separated by commas (Dividers).
Parameter names must be unique within the function.
Parameters are local variables that only exist inside the function.
Arguments must match parameters in number, order, and data type.
Parameter names are case-sensitive.
Functions can have zero or many parameters.

Common Errors

Error: Missing Data Type

FUNCTION add ( a , b )
    RETURN a + b
END FUNCTION
// Syntax error! Parameters missing data types

// Correct:
FUNCTION add ( INT a , INT b )
    RETURN a + b
END FUNCTION

Error: Duplicate Parameter Names

FUNCTION calculate ( INT value , INT value )
    RETURN value + value
END FUNCTION
// Runtime error! Duplicate parameter name

// Correct:
FUNCTION calculate ( INT value1 , INT value2 )
    RETURN value1 + value2
END FUNCTION

Error: Wrong Number of Arguments

FUNCTION multiply ( INT x , INT y )
    RETURN x * y
END FUNCTION

NEW INT result = multiply ( 5 )
// Runtime error! Missing second argument

// Correct:
NEW INT result = multiply ( 5 , 3 )

Error: Argument Type Mismatch

FUNCTION double ( INT n )
    RETURN n * 2
END FUNCTION

NEW INT result = double ( 5.5 )
// Type error! Expected INT, got FLOAT

// Correct:
NEW INT result = double ( 5 )

Error: Missing Divider

FUNCTION add ( INT a INT b )
    RETURN a + b
END FUNCTION
// Syntax error! Missing comma between parameters

// Correct:
FUNCTION add ( INT a , INT b )
    RETURN a + b
END FUNCTION