Crate inline_python
source ·Expand description
Inline Python code directly in your Rust code.
Example
use inline_python::python;
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.
NOTE: Rust nightly toolchain is required. Feature proc_macro_span
is still unstable,
for more details check out issue #54725 - Tracking issue for proc_macro::Span
inspection APIs
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 = Context::new();
c.run(python! {
foo = 5
});
c.run(python! {
assert foo == 5
});
As a shortcut, you can assign a python!{}
invocation directly to a
variable of type Context
to create a new context and run the Python code
in it.
let c: Context = python! {
foo = 5
};
c.run(python! {
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
.
let c: Context = python! {
foo = 5
};
assert_eq!(c.get::<i32>("foo"), 5);
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.
Re-exports
pub use pyo3;
Structs
- An execution context for Python code.