Working with Dip

Dip gives you access to a development environment which comes bundled with Dip - The DDE, short for Dip Development Environment. It gathers inspiration from Python’s IDLE, and has a text editor for you to edit and create dip programs, and an interactive shell, where you can execute and see the output of your programs.

You can evaluate expressions by writing them after Dip>

Dip> 1 + 2
3
Dip> 1 - 3
-2
Dip> 3 + 9
12

Dip basics

Most of Dip’s functions are either reminiscent of Python, or build off them, so people getting started with programming (or even Python programmers for that matter) won’t have any trouble understanding them. These basics are divided into three different categories, data types, builtin functions and the standard library.

Dip’s Data Types

Dip contains 5 data types which you will generally interact with. These are Numbers, Strings, Lists, Functions and Errors.

Numbers

Dip supports integers and decimals, called ints and floats in python. Note that anything following a ‘#’ on the same line is interpreted as a comment and not evaluated.

Dip Beta (Version 0.1)
Type "help", "copyright", "credits" or "about" for more information.

Dip> 10 / 2
5.0
Dip> 1 + 3
4
Dip> 34 * 34
1156

Note that in case of recurring decimals, they are left at 15 decimal places

Dip> 100 / 6
16.666666666666668

Some functions you can perform on numbers are sin, cos, tan and pi.

Dip> sin(45)
0.8509035245341184
Dip> cos(45)
0.5253219888177297
Dip> tan(45)
1.6197751905438615
Dip> pi
3.141592653589793

Strings

A string is a combination of zero or more characters contains inside double-quotes.

Dip> "Hello, Dip!"
"Hello, Dip!"

There are many things that you can do with strings, including adding them, iterating through them, and joining them.

Dip> join("Hello ", "Dip!") Hello Dip!
Dip> print("I am dip, an interpreted programming language")
I am dip, an interpreted programming language
Dip> variable str = "string!"
string!
Dip> for i = 0 to length(str) then print(str / i)
s
t
r
i
n
g
!

Lists

A list is a combination of values inside square braces, separated by commas.
Dip> ["l", "i", "s", "t"]
["l", "i", "s", "t"]

Lists can contain integers, strings, functions and even other lists.

Dip> [[1, 2], [3, 4], [5, 6]]
1, 2, 3, 4, 5, 6 Dip>

There are many things that you can do with lists, including ‘join’, which joins two lists, ‘add’, which adds an element to a list, ‘remove’, which removes an element at an index from a list.

Dip> variable new_list = join([1, 2, 3], [4, 5, 6])
1, 2, 3, 4, 5, 6
Dip> new_list
1, 2, 3, 4, 5, 6
Dip> add(new_list, 7)
1, 2, 3, 4, 5, 6, 7
Dip> new_list
1, 2, 3, 4, 5, 6, 7
Dip> remove(new_list, 4)
5
Dip> new_list
1, 2, 3, 4, 6, 7
Dip>

Note that the ‘remove’ function removes the element from the 4th index, which in this case, is 5.

Functions

Functions can be defined using the 'function' keyword, followed by the name of the function, and then its arguments in parenthesis. For a single line function, you can use '->' and then type what you want it to do. For a multi-line function, enter a new line and end the function with an end statement

Dip> function add(a, b) -> print(a + b)
function add

function odd_or_even(number)
if number % 2 == 0 then print("even") else print("odd")
end

Some functions return values. These values can then be assigned to variables

Read more about functions in the builtin functions section!

Errors

Errors are generated automatically when the user tries to evaluate invalid code. Dip contains 5 different error types, Illegal Character Error, Expected Character Error, Runtime Errors, Invalid Syntax Errors and Custom Errors. Custom errors can also be generated using the ‘error’ function followed by a string inside parenthesis. The string will be the message of the error. Errors in the interpreter can help the user by providing insightful commentary.

Illegal Character Errors - Called when an illegal character is found Dip> @
Illegal Character: '@'
File Dip Shell, line 1
@
^


Expected Character Errors - Called when a character that was supposed to be in a certain position is not found

Invalid Syntax / Character Not Found: Expected 'end'
File , line 1
function add(a, b); return a + b ^

Runtime Errors - A range of errors that might rise at runtime

Runtime Error: Illegal operation - check you are comparing two different data types (eg. integer and string) File Dip Shell, line 1

1 - "1"
^^^^^^^


Invalid Syntax Errors - Called when the syntax is invalid
Invalid Syntax / Character Not Found: Expected int, float, identifier, '+', '-', '(', '[', if, for, while or function
File Dip Shell, line 1

5 === 5
^


Custom Errors - User Defined errors that can be called any time

Dip> error("test error")
Custom Error: test error
These errors can then be used like the built-in errors.

Statements in Dip

In Dip, each statement is separated by a newline.

In the above example, Dip's lexer categorises these as two statements. If you wish to make two statements in one line, these can be separated by a semicolon

Variables in Dip

Variables in Dip can be assigned with the 'variable' keyword, like so (variables must be assigned a value at declaration):

Operators in Dip

Dip supports 5 operators, +, -, *, / and %

Conditionals in Dip

Conditional statements, or an if then statement in Dip can be written like so:

Running Python Code

variable python_code = "
# Program make a simple calculator

# This function adds two numbers
def add(x, y):
    return x + y

# This function subtracts two numbers
def subtract(x, y):
    return x - y

# This function multiplies two numbers
def multiply(x, y):
    return x * y

# This function divides two numbers
def divide(x, y):
    return x / y


print('Select operation.')
print('1.Add')
print('2.Subtract')
print('3.Multiply')
print('4.Divide')

while True:
    # Take input from the user
    choice = input('Enter choice(1/2/3/4): ')

    # Check if choice is one of the four options
    if choice in ('1', '2', '3', '4'):
        num1 = float(input('Enter first number: '))
        num2 = float(input('Enter second number: '))

        if choice == '1':
            print(num1, '+', num2, '=', add(num1, num2))

        elif choice == '2':
            print(num1, '-', num2, '=', subtract(num1, num2))

        elif choice == '3':
            print(num1, '*', num2, '=', multiply(num1, num2))

        elif choice == '4':
            print(num1, '/', num2, '=', divide(num1, num2))
        break
    else:
        print('Invalid Input')
"


evaluate(python_code)

Dip’s Standard Library

The standard library is a collection of custom functions written in Dip that gets automatically loaded when you run the Dip interface.

Loops in Dip

There are two major types of loops in Dip, for loops and while loops.

For Loops

Each for loop begins with the word ‘for’ and then defines its range. This is done like this:

After this, using the then keyword, users can specify what needs to be done for each of these values.

Note that any variable, such as 'letter' or 'word' can be used as an iterable in for loops. I have used 'i' just for the purpose of tradition. Learn more about using i in for loops.

While Loops

Note that a ‘;’ defines a new line Note that while loops can use any variable as an iterable

Recursion in Dip

Here is an example of a recursive program in Dip - A function to calculate the factorial of a number

variable fact = 1
if term >= 1 then
    for i = 1 to term + 1 then
        variable fact = fact * i
    end
end
say(fact)

end

Another function in Dip - the famous Fibonacci function

variable n1 = 0
variable n2 = 1
variable count = 0

if nterms <= 0 then print("Input a positive integer")
if nterms == 1 then
    print("Fibonnaci sequence upto" + " 1" + ":")
    print(n1)
else
    print("Fibonacci sequence:")
    while count < nterms then
        print(n1)
        variable nth = n1 + n2
        variable n1 = n2
        variable n2 = nth
        variable count = count + 1
    end
end

end