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Add
Python package module for Python+Chapel interop (#26156)
Adds a new package module, `Python`, which supports calling Python code
from Chapel.
For example, the following Chapel progam use the python interface to
`BeautifulSoup` to parse HTML
```chapel
import Python;
use URL;
use List;
proc main() {
const url = 'https://chapel-lang.org/docs/main/language/spec/interoperability.html';
var htmlReader = openUrlReader(url);
var html = htmlReader.readAll(string);
var interp = new Python.Interpreter();
var mod = new Python.Module(interp, "bs4");
var cls = new Python.Class(mod, "BeautifulSoup");
var soup = cls(html, 'html.parser');
var res: list(owned Python.ClassObject?);
res = soup.callMethod(res.type, "find_all", "h3");
for c in res {
writeln(c!.getAttr(string, "text"));
}
}
```
As an another example, this simple program compiles an runs a Python
lambda from Chapel code
```chapel
import Python;
config const n = 10;
config const func = "lambda x,: x + 1 if x % 2 != 0 else x";
proc apply(interp: borrowed, type t, arr, l) {
var lambdaFunc = new Python.Function(interp, l);
var res: [arr.domain] t;
for i in arr.domain {
res(i) = lambdaFunc(t, arr(i));
}
return res;
}
proc main() {
var interp = new Python.Interpreter();
var data: [1..#n] int = 1..#n;
writeln(" data: ", data);
var res = apply(interp, int, data, func);
writeln("res: ", res);
}
```
Future work:
- Convert classes to a hierarchy under `Value` so that more
implementation can be shared and the Chapel interface can better imitate
python
- Add special support for common python types as sub-classes of value,
to avoid round tripping values through chapel in many cases
- Support common operators like add. These can be called today as dunder
methods (`.call("__add__", ...)`), but it would be nice to support
native operators like `+`
- Add the ability to compile arbitrary chapel strings, beyond just
lambdas
- Setup python to use Chapel stdout/stderr
- Add custom adapters for Chapel arrays to allow python functions to
operate on Chapel arrays, without copying
- Support python context managers as Chapel context managers
- Fully support Python sets, Python dictionaries, Chapel sets, Chapel
maps, Chapel associative arrays, and Chapel associative domains
- Make sure all python objects are properly reference counted
- Resolve TODO with LLVM IR verification:
#26235
[Reviewed by @DanilaFe]- Loading branch information
