Expand description
Moisture is a Rust code parsing library with a callback
interface. It is based on syn, quote and proc-macro2 and is
intended to be used with procedural macros.
What Moisture does specifically is parse the entire syntax tree provided by a token stream and
issue callbacks to certain objects for potential modification. A basic example:
use proc_macro2::{Span, TokenStream};
use quote::{quote, ToTokens};
use syn::{LitStr, Result, parse2};
use syn::spanned::Spanned;
use moisture::*;
fn str_callback(moisture: &Moisture, context: &Context, tokens: TokenStream) -> Result<TokenStream> {
let lit_str = parse2::<LitStr>(tokens.clone())?;
if lit_str.value() == "foo" { Ok(LitStr::new("bar", lit_str.span()).to_token_stream()) }
else { let result = moisture.lit_str(context, tokens)?; Ok(result) }
}
let mut moisture = Moisture::new();
moisture.register_callback(CallbackType::LitStr, str_callback);
let foo_stream = quote! { "foo" };
let bar_stream = run_moisture!(moisture, CallbackType::LitStr, foo_stream);
let bar_lit = parse2::<LitStr>(bar_stream).unwrap();
assert_eq!(bar_lit.value(), "bar");
let baz_stream = quote! { "baz" };
let same_stream = run_moisture!(moisture, CallbackType::LitStr, baz_stream);
let baz_lit = parse2::<LitStr>(same_stream).unwrap();
assert_eq!(baz_lit.value(), "baz");A significant chunk of syn types are supported. See CallbackType for a
list of supported syn types.
Macros
The macro to use in procedural macros when parsing with Moisture.
Structs
The callback context of the given syntax callback.
The structure which holds and processes the callbacks.
Enums
The type of callback to register with the Moisture structure.
Functions
Get a PatType object from a TokenStream.