DUE - Statements

Language Statements

Statement	Description
print/cls	Special Output Console Statements
print	Prints the following expression to the console and moves to the next line
locate	Locates where the print will take place in rows, columns
if/elseif/else	Conditional execution of the code
while	Executes a block of code until the condition is false
break	Breaks out of the current while loop
continue	Continues the current while loop skipping the rest of the body
return	Returns a value from a function
end	Used in BASIC-style to indicate the end of `if` or `while`
var	Declares a variable
const	Declares a constant, a variable that can't be modified!
func	Declares a function block
AND/OR	Boolean operators

Console Statements

These statements are a quick and dirty way to output information. By default, cls does not do anything but print will simply call Debug.WriteLine internally.

The behavior can be change, to forward the output to a serial port or a display for example. See API page from more details.

Tip

print will format double ToString("N4")

Execution Statements

while, if/elseif/else, continue, break and 'return' work just like most globally-acceptable programming languages.

The `end` statement

DUE supports multiple code block types. When basic-style is selected, the end statement marks the end of a block.

if x > 10
  print x
end

In the case other style is used, like C-style, using end is not needed and not allowed.

if (x>10) {
  print(x);
}

This is not allowed

if (x>10){
  print(x);
end

var

var is how variables are created. var will automatically select the correct type and will even change the type on the next assignment, like change it from numerical to string.

Numerical

Variables are always double-type and must always have a starting value var x = 10 is good but var x is not allowed.

Strings

var s = "Hello DUE" creates a variable of a string type.

Just like modern languages, strings can be combined. var s = "Hello " + "DUE".

With strings, numerical variable or constants are automatically converted to strings internally. print "x= " + x.

Both single quote and double-quote are supported and work the same. print 'hi'.

Arrays

Arrays, and arrays of arrays, are supported. It is important to note that arrays hold an array of var and each var in itself can be any kind, even another array.

var numbers = [1, 2, 3, 4]
var names = ["DUE", "is", "amazing"]
var mix = ["Hi", 55, 96.34]

Arrays can even contain other arrays

var setsOfNumbers = [[1,3,5], [2,4,6]]

Array elements are indexed starting zero.

var numbers = [1, 2, 3, 4]
print numbers[2] // Will access the 3rd element in the array

Creating an empty array is supported var arr = [].

Tip

Creating an empty array of specific length is supported through the Array functions from Standard Library.

const

const is a special type of variable that can't be changed.

const x = 5
const s = "Hello"
// these are not allowed
x = 10
s = "Bye!"

Arrays are slightly different as in the values can be changed but not the array itself.

const a = [1, 2, 5]
a[2] = 3
// this is not allowed
a = 5

Functions (func)

Functions are added using func statement.

func printsomething()
  print("Hello There!")
end
printsomething()

Of course, curly brackets can be used instead, and even semicolons!

func printsomething() {
  print "Hello There!";
}
printsomething()

Passing arguments to functions is supported.

func greet(name)
  print "Hello " + name
end

greet("Gus")
// This will show Hello Gus on the output window

Functions can also return values

func add(x, y) 
  return x + y
end

var answer = add(32, 10)

Functions can also be added from C# through Extensions.

Boolean Operators

Some programming languages use && and some use AND to check of 2 statements are true, similarly they have || and OR.

if speed > 100 AND temp < 32
	print "Slow down!"
end
if (speed > 200 && temp < -40) {
	print("Goodbye!");
}

Bitwise Operators

Not currently supported.

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