Delta Documentation

• Basic usage

• Type annotations

• Supported features

• Additional features

Delta can be written in Python, and has .dt extension.

Type annotations are required when declaring new identifiers.

Example:

• valid:

x: int = 0
print(x)
x = 1
print(x)

• invalid:

x = 0
print(x)
x = 1
print(x)

Delta requires type annotations when declaring new identifiers

Variables

Basic

number: int = 0 
number: int #This is also vaild

Subscripts

list_var: list[int]
dict_var: dict[str, int] #str as key, int as value
set_var: set[float]
tuple_var: tuple[int, float, str] #datatypes of elements must be specified

mixed_var: list[tuple[str, dict[int, str]]]

Functions

Basic

def print_person(name: str, age: int) -> None:
    print(name, age)

Keyword arguments

def calc_vel(target: float, base: float = 0) -> float:
    return target - base

Example:

def print_person(name: str, age: int) -> None:
    print(f"{name} is {age} years old")

def print_people(people: list[tuple[str, int]]) -> None:
    for person in people:
        print_person(person[0], person[1])


people: list[tuple[str, int]] = []
while True:
    name: str = input("Enter name: ")
    if name == "":
        break
    age: int = int(input("Enter age: "))
    people.append((name, age))

print_people(people)

Delta is currently in pre-release phase, and doesn't support all the features of Python yet.

Supported keywords:

• if
• elif
• else
• for
• while
• from ... import ...
• pass
• break
• continue
• return
• assert
• del

Supported special syntaxes:

• f-strings

Supported built-in functions:

built-in:

• print(object, end="\n") -> None
• input("prompt") -> str
• len(iterable) -> int
• int(str) -> int
• float(str) -> float
• str(object) -> str
• list(str) -> list[str]
• min(str|list|set) -> elem dtype
• max(str|list|set) -> elem dtype
• sum(str|list|set) -> elem dtype
• sorted(str|list|set) -> list[elem dtype]
• round(float) -> float
• abs(int|float) -> int|float

special functions:

• cpp(str)

Example uses can be found here