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#![forbid(unsafe_code)]
extern crate proc_macro;
use proc_macro::TokenStream;
use proc_macro_hack::proc_macro_hack;
use syn::parse::Parse;
use syn::parse::ParseStream;
use syn::parse::Result;
use syn::{Token, parse_macro_input};
use quote::quote;
use syn::Expr;
use syn::LitInt;
struct ArrayInit {
value: Expr,
quantity: LitInt,
}
impl Parse for ArrayInit {
fn parse(input: ParseStream) -> Result<Self> {
let value: Expr = input.parse()?;
input.parse::<Token![;]>()?;
let quantity: LitInt = input.parse()?;
Ok(ArrayInit {
value,
quantity,
})
}
}
#[proc_macro_hack]
pub fn arr(input: TokenStream) -> TokenStream {
let ArrayInit {
value,
quantity
} = parse_macro_input!(input as ArrayInit);
let iter = std::iter::repeat(value).take(quantity.value() as usize);
let result = quote! {
[#(#iter),*]
};
result.into()
}