cleanup AST builder functionality

[bungcip]

• remove unused function & impl
  • impl<'a> Make<Unsafety> for &'a str
  • impl<'a> Make<Constness> for &'a str
  • impl Make<TokenStream> for Vec<String>
  • impl Make<PathArguments> for ParenthesizedGenericArguments
  • fn parenthesized_args
• refactor mk().vis() usage so we can remove impl<'a> Make<Visibility> for &'a str
• refactor mk().set_mutbl() usage so we can remove impl<'a> Make<Mutability> for &'a str
• refactor mk().unary_expr() usage so we can remove impl<'a> Make<UnOp> for &'a str
• unify impl Make<TokenStream> for Vec<&str>, impl Make<TokenStream> for Vec<u64>, and impl Make<TokenStream> for Vec<Meta> functionality to use fn comma_separated

[kkysen]

If this can be hoisted to the top-level, that'd be preferable.

[bungcip]

maybe we can create a new module, lets call it transform, which contain all helper function that transform a rust AST to another rust AST. so we can put helper function like this not() and unparen() in there. However i prefer doing that in another PR rather than this

[kkysen]

With an iterator-based fn comma_separated, you can simplify this to:

impl Make<TokenStream> for Vec<&str> {
    fn make(self, _mk: &Builder) -> TokenStream {
        comma_separated(self.iter().map(|&s| Ident::new(s, Span::call_site())))
    }
}

impl Make<TokenStream> for Vec<u64> {
    fn make(self, _mk: &Builder) -> TokenStream {
        comma_separated(self.iter().map(|&s| Literal::u64_unsuffixed(s)))
    }
}

impl Make<TokenStream> for Vec<Meta> {
    fn make(self, _mk: &Builder) -> TokenStream {
        comma_separated(self.iter())
    }
}

[kkysen]

Suggested change

	fn comma_separated<T, F>(items: Vec<T>, f: F) -> TokenStream
	where
	F: Fn(&mut TokenStream, T),
	{
	let mut tokens = TokenStream::new();
	let mut first = true;
	for item in items {
	if !first {
	TokenTree::Punct(Punct::new(',', Spacing::Alone)).to_tokens(&mut tokens);
	} else {
	first = false;
	}
	f(&mut tokens, item);
	}
	tokens
	}
	fn comma_separated<I, T>(items: I) -> TokenStream
	where
	I: Iterator<Item = T>,
	T: ToTokens + Clone,
	{
	let items = items.map(|items| items.to_token_stream());
	let comma = TokenTree::Punct(Punct::new(',', Spacing::Alone)).into_token_stream();
	intersperse(items, comma).collect()
	}

If you add itertools to c2rust-ast-builder (which we already use for c2rust-transpile), this could be a lot simpler.

[bungcip]

if it is ok to add new dependencies crate, i will add it tomorrow. cannot wait for rust-lang/rust#79524 to become stable😃

[kkysen]

I'm not sure getting rid of all of these is helpful. "!" is pretty easy to read and understand (although things like "not" and the other non-standard spellings for things seem bad). It has the downside of not being as easily searchable since it's not tied to a symbol like UnOp::Not, but it's also easier to read and write in a bunch of ways.

[bungcip]

I think is more readable for all unary_expr() usage in transpile to just use mk().deref_expr(), mk().neg_expr(), and mk().not_expr(). I can create follow up PR for the refactor