brf_macro/
lib.rs

1#![warn(missing_docs)]
2
3//! brf-macro is a simple procedural macro to generate unicode braille strings from
4//! [Braille Ascii](https://en.wikipedia.org/wiki/Braille_ASCII), commonly used in BRF (Braille Ready File) files.
5
6use braille_ascii::{ascii::AsciiString, BrailleAsciiString};
7use proc_macro::TokenStream;
8use quote::ToTokens;
9
10/// Creates a static `str` of Unicode Braille from a string literal in Braille ASCII format.
11///
12/// The argument to this macro must be a `str` literal containing only ASCII characters. ASCII
13/// control characters (codepoints < 32) will be included in the output string unchanged.
14#[proc_macro]
15pub fn brf(input: TokenStream) -> TokenStream {
16    let literal: syn::LitStr =
17        syn::parse(input).expect("brf macro can only be used with a string literal argument");
18    let ascii = AsciiString::from_ascii(literal.value()).unwrap();
19    let braille = BrailleAsciiString::from_ascii(ascii).to_unicode_braille();
20    let braille_literal = syn::LitStr::new(&braille, literal.span());
21    braille_literal.into_token_stream().into()
22}
23
24/// Creates a static `&[u8]` of Braille dot patterns from a string literal in Braille ASCII format.
25///
26/// The argument to this macro must be a `str` literal containing only ASCII characters. Any ASCII
27/// control characters (codepoints < 32) will be rendered as empty Braille cells.
28#[proc_macro]
29pub fn brf_bytes(input: TokenStream) -> TokenStream {
30    let literal: syn::LitStr =
31        syn::parse(input).expect("brf macro can only be used with a string literal argument");
32    let ascii = AsciiString::from_ascii(literal.value()).unwrap();
33    let braille = BrailleAsciiString::from_ascii(ascii).to_unicode_braille();
34    let cells: Vec<u8> = braille
35        .chars()
36        .map(|c| {
37            if c < ' ' {
38                0
39            } else {
40                u32::from(c).to_le_bytes()[0]
41            }
42        })
43        .collect();
44    let braille_literal = syn::LitByteStr::new(&cells, literal.span());
45    braille_literal.into_token_stream().into()
46}