#python #inline #embed #macro


Inline Python code directly in your Rust code

7 unstable releases (3 breaking)

✓ Uses Rust 2018 edition

0.4.0 Nov 22, 2019
0.3.3 Nov 22, 2019
0.3.2 Oct 8, 2019
0.3.1 Jun 19, 2019
0.1.0 Apr 17, 2019

#20 in FFI

Download history 12/week @ 2019-08-09 2/week @ 2019-08-16 40/week @ 2019-08-23 14/week @ 2019-08-30 18/week @ 2019-09-06 11/week @ 2019-09-13 72/week @ 2019-09-20 63/week @ 2019-09-27 57/week @ 2019-10-04 14/week @ 2019-10-11 19/week @ 2019-10-18 48/week @ 2019-10-25 25/week @ 2019-11-01 38/week @ 2019-11-08 38/week @ 2019-11-15

159 downloads per month
Used in 1 crate


445 lines


Inline Python code directly in your Rust code.


use inline_python::python;

fn main() {
    let who = "world";
    let n = 5;
    python! {
        for i in range('n):
            print(i, "Hello", 'who)

How to use

Use the python!{..} macro to write Python code directly in your Rust code. You'll need to add #![feature(proc_macro_hygiene)], and use a nightly version of the compiler that supports this feature.

Using Rust variables

To reference Rust variables, use 'var, as shown in the example above. var needs to implement pyo3::ToPyObject.

Re-using a Python context

It is possible to create a Context object ahead of time and use it for running the Python code. The context can be re-used for multiple invocations to share global variables across macro calls.

let c = inline_python::Context::new();
python! {
  #![context = &c]
  foo = 5
python! {
  #![context = &c]
  assert foo == 5

Getting information back

A Context object could also be used to pass information back to Rust, as you can retrieve the global Python variables from the context through Context::get_global.

Syntax issues

Since the Rust tokenizer will tokenize the Python code, some valid Python code is rejected. The two main things to remember are:

  • Use double quoted strings ("") instead of single quoted strings ('').

    (Single quoted strings only work if they contain a single character, since in Rust, 'a' is a character literal.)

  • Use //-comments instead of #-comments.

    (If you use # comments, the Rust tokenizer will try to tokenize your comment, and complain if your comment doesn't tokenize properly.)

Other minor things that don't work are:

  • Certain escape codes in string literals. (Specifically: \a, \b, \f, \v, \N{..}, \123 (octal escape codes), \u, and \U.)

    These, however, are accepted just fine: \\, \n, \t, \r, \xAB (hex escape codes), and \0

  • Raw string literals with escaped double quotes. (E.g. r"...\"...".)

  • Triple-quoted byte- and raw-strings with content that would not be valid as a regular string. And the same for raw-byte and raw-format strings. (E.g. b"""\xFF""", r"""\z""", fr"\z", br"\xFF".)

  • The // and //= operators are unusable, as they start a comment.

    Workaround: you can write ## instead, which is automatically converted to //.

Everything else should work fine.

License: BSD-2-Clause


~51K SLoC