From d82f5da5aef06a0989430c5ea9cc60a483f1fbff Mon Sep 17 00:00:00 2001 From: HampusM Date: Sat, 12 Nov 2022 15:01:19 +0100 Subject: feat: add project & repeat_char macro --- src/lib.rs | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 src/lib.rs (limited to 'src') diff --git a/src/lib.rs b/src/lib.rs new file mode 100644 index 0000000..5649972 --- /dev/null +++ b/src/lib.rs @@ -0,0 +1,62 @@ +#![deny(clippy::all)] +#![deny(clippy::pedantic)] +#![deny(missing_docs)] + +//! Utility macros that should be in std but is not. + +use std::iter::repeat; + +use proc_macro::TokenStream; +use quote::quote; +use syn::parse::Parse; +use syn::{parse_macro_input, LitChar, LitInt, Token}; + +/// Repeats a character N number of times resulting in a string literal. +/// +/// # Arguments +/// Seperated by commas. +/// +/// - The character to repeat +/// - Number of times to repeat it. +/// +/// # Examples +/// ``` +/// # use utility_macros::repeat_char; +/// +/// let eight_o = repeat_char!('o', 8); +/// +/// assert_eq!(eight_o, "oooooooo"); +/// ``` +#[proc_macro] +pub fn repeat_char(input: TokenStream) -> TokenStream +{ + let RepeatCharMacroArgs { character, count } = + parse_macro_input!(input as RepeatCharMacroArgs); + + let repeated = repeat(character.value()).take(count).collect::(); + + quote! { + #repeated + } + .into() +} + +struct RepeatCharMacroArgs +{ + character: LitChar, + count: usize, +} + +impl Parse for RepeatCharMacroArgs +{ + fn parse(input: syn::parse::ParseStream) -> syn::Result + { + let character = input.parse::()?; + + input.parse::()?; + + let count = input.parse::()?.base10_parse::()?; + + Ok(Self { character, count }) + } +} -- cgit v1.2.3-18-g5258