fn render_binding()

in starlark_derive/src/render.rs [238:296]

• 59 lines of code
• 2 McCabe index (conditional complexity)

fn render_binding(x: &StarFun) -> TokenStream {
    let span = x.args_span();
    match x.source {
        StarFunSource::Parameters => {
            let StarArg {
                span,
                attrs,
                name,
                ty,
                ..
            } = &x.args[0];
            let span = *span;
            quote_spanned! { span=> #( #attrs )* let #name : #ty = __args; }
        }
        StarFunSource::ThisParameters => {
            let StarArg {
                span,
                attrs,
                name,
                ty,
                ..
            } = &x.args[1];
            let span = *span;
            let this = render_binding_arg(&x.args[0]);
            quote_spanned! {
                span=>
                #this
                #( #attrs )* let #name : #ty = __args;
            }
        }
        StarFunSource::Argument(arg_count) => {
            let bind_args = x.args.map(render_binding_arg);
            quote_spanned! {
                span=>
                let __args: [_; #arg_count] = __signature.collect_into(__args, eval.heap())?;
                #( #bind_args )*
            }
        }
        StarFunSource::Positional(required, optional) => {
            let bind_args = x.args.map(render_binding_arg);
            if optional == 0 {
                quote_spanned! {
                    span=>
                    __args.no_named_args()?;
                    let __required: [_; #required] = __args.positional(eval.heap())?;
                    #( #bind_args )*
                }
            } else {
                quote_spanned! {
                    span=>
                    __args.no_named_args()?;
                    let (__required, __optional): ([_; #required], [_; #optional]) = __args.optional(eval.heap())?;
                    #( #bind_args )*
                }
            }
        }
        ref s => unreachable!("Unknown StarFunSource: {:?}", s),
    }
}