hdytto: How do you turn this on

A library adding new syntax into your Python. i.e. It is NOT Pythonic :)

• Compatibility
• Getting Started
  • REPL
• hdytto Reference
  • Increment / Decrement
  • do...while
  • Comment
  • const

Compatibility

• Python >=3.8

Getting Started

Install from PyPI:

$ pip install hdytto

This library cannot be used by import hdytto as in other libraries, but the usage is simple. At first, make sitecustomize.py:

from hdytto import register_hdytto
register_hdytto()

Set the environmental variable PYTHONPATH the path to the directory containing the sitecustomize.py (e.g. export PYTHONPATH=.). Then, run main.py:

# coding: hdytto

a = 5
print(a++)
print(a)

The output will be

5
6

REPL

Additionally, make .pythonrc.py:

import sys
import sitecustomize
sys.stdin.reconfigure(encoding='hdytto')

Set the environmental variable PYTHONSTARTUP the path to this .pythonrc.py (e.g. export PYTHONSTARTUP=.pythonrc.py). Then, type python:

$ python
>>> a = 5
>>> a++
5
>>> do:
...     b = ++a
...     while b < 10
...
>>> b
10

hdytto Reference

Increment / Decrement

Syntax

x++
++x
x--
--x

Example

# coding: hdytto
a = 5
print(a++)
print(++a)
b = 10 - --a
print(b--)

Output:

5
7
4

do...while

Syntax

do:
    statement
    while condition

Example

# coding: hdytto
do:
    a = 5
    while a < 3
do:
    b = a * 2
    while a++ < 10:
        pass
    while b <= 20
print(b)

Output:

22

Comment

Syntax

/* */

Example

# coding: hdytto
a = /* foo */ 10
print(a)
if a == 10:
    b = 5
    /*b = 10
print(a - 20)*/
print(b)

Output:

10
5

const

Syntax

const name = value

Example

# coding: hdytto

import time

def foo(x, const y):
    y = 20
    print(x + y)

print('long time process here.')
const a = 30
time.sleep(a) # a process requiring long time

foo(1, 2)

Output:

  File "main.py", line 6
    y = 20
         ^
SyntaxError: invalid assignment to const y

SyntaxError: encoding problem: hdytto

This is SyntaxError, so does not require running the process requiring long time.

Caution

hdytto's const only prohibits =, +=, -=, *=, /=, %=, &=, |=, ^=, <<=, >>=, **=, //=, @=, :=, otherwise is allowed (e.g. const l = [] and l.append(5) is allowed).