Inline Python code directly in your Rust code.

Example

#![feature(proc_macro_hygiene)]
use inline_python::python;

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

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.

# #![feature(proc_macro_hygiene)]
# use inline_python::python;
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.