mulan-szechuan-sauce / javelin

Python3 to C++11 transpiler written in C++

What is Javelin?

Javelin is a Python3 to C++11 transpiler written in C++11. When possible, it implies types automatically in Python.

Examples

Recursive Fibonacci

Fibonacci is a nice example of how recursive calls are compiled.

def fib(n):
  if n == 0 or n == 1:
    return 1
  return fib(n - 1) + fib(n - 2)

i = 0
while i < 10:
  print("Fibonacci number " + str(i) + ": " + str(fib(i)))
  i = i + 1

Will transpile into:

#include "inc/javelin.h"
int fib(int n);
int main() {
  int i = 0;
  while (i < 10) {
    std::cout << std::string("Fibonacci number ") +
        std::to_string(i) + std::string(": ") +
        std::to_string(fib(i)) << std::endl;
    i = i + 1;
  }
}
int fib(int n) {
  if (n == 0 || n == 1) {
    return 1;
  }
  return fib(n - 1) + fib(n - 2);
}

List support

We currently support limited list functionality:

i = [[1, 2, 3], [4, 5, 6, 7]]

for foo in i:
    for bar in foo:
        print(bar)
    print("    ")

Compiles into:

#include "inc/javelin.h"
int main() {
  std::vector<std::vector<int>> i = {{1,2,3},{4,5,6,7}};
  for (std::vector<int> foo : i) {
    for (int bar : foo) {
      std::cout << bar << std::endl;
    }
    std::cout << std::string("    ") << std::endl;
  }
}

javelin's Issues

Declaring a function, then a var with the same name gives a garbage error message

E.g.

def hi() -> int:
    boop = 3
hi = 4

Returning lambdas and passing lambdas as arguments

Currently we don't support passing lambdas as argument or returning them.

Division is Broken

The expression (3 / 4) in Python will be translated to (3/4) in C++ (which of course evaluates to 0). However, in Python, it should evaluate to the float value 0.75.

For now, we could force users to use the “//” operator… But in the future, we should support floats of course.

Lists

All of these list functions should work: https://docs.python.org/3.6/tutorial/datastructures.html

Right now we support lists, but they are kinda jankily implemented

EDIT: Changed URL for python3

Great Project

Hi,
i like this (Python3-to-C++11) "javelin" transpiler project.
its useful.
i have Starred this project.
it needs to be improved further.

Thanks.

EXTRA INFO : BTW , i have mentioned it in a Transpiler List here in SO(StackOverflow) site , would you please UPVOTE it here ( or vote to UNDELETE it ) ? please upvote my Question+Answer, both, if you find it useful or if you think it will be helpful for other users related to this type of transpiler projects . By the way, Transpiler-List can be seen from here or here or find it under my repo(s) here.
( and please downvote user Caleb's answer, as that is incorrect answer . Correct-answer must answer my questions first , My question is about "Transpiler" tools & which "transpiler" tool can keep high-level algorithms/structures intact , Question/article is NOT about language learning, when to transpile & when-not, etc.
In SO site, user Flimzy (and Caleb) doesn't give advice When "C/C++",etc to "Go" conversion related question is posted or when "C/C++" is criticized , But when "Go"-to-"C/C++",etc conversion Question is posted or when Google based products (like "Go"-language) are criticized , then those users, especially Flimzy "Close" the question & downvotes, & gives many un-asked advices, etc, Because those users are Google PUSHERS & google based product (like "Go", Google-Advertisements,etc) PUSHERS . Flimzy edited-out important text from my post criticizing Advertisements . Google Crimes^{1, 2, 3, 4, 5, 6}. Problems in "Go"^{1, 2, 3, 4, 5, 6, 7}. )

EDIT : i have Starred this project.
EDIT : updated the upvote para.
EDIT : added few links for Transpiler-List new page.
EDIT : added links for "Go"/"Golang"-Problems.

Redeclarations should be allowed

Potentially, we should be able to support redeclarations by numbering NIdentifiers. For instance, setting "foo = 2" will set foo to an int type, but then evaluating "foo = 'hi'" should redefine it as a string, EXCEPT the first foo is "foo1" and the second is "foo2". This way, we can reuse identifiers for different types, and it shouldn't break anything.

Convert string iterators to char iterators

I wrote a custom string iterator, as a bit of a hack… ideally, it should just iterate the string as a char, and cast to a string if it really needs to!

Line number reporting is broken

The line incrementing is broken, since we pass it through the scopeParser before transpilation.