/
count_compound_ops.rs
36 lines (30 loc) · 1.16 KB
/
count_compound_ops.rs
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// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// no-prefer-dynamic
#![feature(proc_macro)]
#![crate_type = "proc-macro"]
extern crate proc_macro;
use proc_macro::{TokenStream, TokenKind, OpKind, Literal, quote};
#[proc_macro]
pub fn count_compound_ops(input: TokenStream) -> TokenStream {
assert_eq!(count_compound_ops_helper(quote!(++ (&&) 4@a)), 3);
TokenKind::Literal(Literal::u32(count_compound_ops_helper(input))).into()
}
fn count_compound_ops_helper(input: TokenStream) -> u32 {
let mut count = 0;
for token in input {
match token.kind {
TokenKind::Op(c, OpKind::Alone) => count += 1,
TokenKind::Sequence(_, tokens) => count += count_compound_ops_helper(tokens),
_ => {}
}
}
count
}