Implement kwargs in function calls #115
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This doesn't enforce ordering of non-keyword and keyword arguments, and doesn't actually use the keywords (the arguments will still be passed through in order as positional).
| @@ -137,7 +137,8 @@ pub enum Expression { | |||
| }, | |||
| Call { | |||
| function: Box<Expression>, | |||
| args: Vec<Expression>, | |||
| // parameters are (None, value), kwargs are (keyword name, value) | |||
| args: Vec<(Option<String>, Expression)>, | |||
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Are kwargs allowed before normal args? If not, I would suggest two vectors, args and kwargs. In any case I would like to have a seperate struct for kwargs with a name and expression member.
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They aren't, but these are created in the lalrpop-generated code. I couldn't work out a good way of expressing the ordering there, so at the moment, we enforce the ordering in the compiler.
The problem is, I think, that with foo(x, y="z") the parser can't know when it examines y whether or not it is a positional argument or a keyword argument.
My grammar-fu is very weak though, so there may well be a way of handling that!
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Okay, I'll have a look later on.
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This would be cool, so we could implement |
vm/src/vm.rs
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| .to_vec() | ||
| .unwrap() | ||
| .iter() | ||
| .map(|pyobj| pyobj.to_str().unwrap()) |
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vm.to_str might be the better option here?
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These are the keyword argument names, which can only be literal strings:
$ python -c 'foo("s"+"a"="foo")'
File "<string>", line 1
SyntaxError: keyword can't be an expression
so we shouldn't ever get in to a case where this isn't a string; I've just pushed up a commit to use objstr::get_value directly.
vm/src/pyobject.rs
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| @@ -512,21 +512,30 @@ impl fmt::Debug for PyObject { | |||
| #[derive(Debug, Default, Clone)] | |||
| pub struct PyFuncArgs { | |||
| pub args: Vec<PyObjectRef>, | |||
| // TODO: add kwargs here | |||
| pub kwargs: Option<Vec<(String, PyObjectRef)>>, | |||
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Btw, is option required? An empty vector means no kwargs?
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Nope, not required; just pushed up a fix.
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