SIMPLELANG

A simple programming language.

Made for JUST FOR STUDYING using lark-parser and parsing itself.

Description

SIMPLELANG has below feature.

• Only support number. There is no string, list, object, and so on.
• Basic arithmetic operations (addition, subtraction, multiplication, division)
• Declaring and using variables.
• Declaring functions.
• Calling functions with local environments.

Basic arithmetic operations

You can use +, -, *, /, ().

Declaring variables

You can declare new variables with variable_name = <expression>.

No need to type keyword like var, val, let, const.

And you can use overwrite value of variables by simply assign value again.

To refer the value of variables, simply call its name.

a = 1;
a; => 1

b = a + 2;
b; => 3

Declaring functions

The keyword to declare function is def. And def followed with name of function, and parameters(surrounded with parenthesis), and its content (surrounded with braces)

Like below.

def foo ( a, b, c ) {
  return a + b + c;
}

Calling functions

You can call declared function with its name. and you can pass arguments with brackets.

d = foo [ 1, 2, 3 ]

Return

Return statement returns value. And following statements or expressions are ignored.

return 2;

// below lines are meaningless
a = 1;
b = 3;
...

Conclusion

An example of SIMPLELANG program.

a = 5;

def func ( b , c ) {
  a = 4;
  return a + b * c;
}

c =  func [ 2 , 4 ];

return c;

This returns 12.0.