9 releases
new 0.0.8 | Jun 22, 2024 |
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0.0.7 | Jun 12, 2024 |
0.0.2 | May 30, 2024 |
#95 in Procedural macros
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Used in unsynn-rust
81KB
1.5K
SLoC
unsynn (from german 'unsinn' for nonsense) is a minimalist rust parser library. It achives this by leaving out the actual grammar implementations and compromise on simpler error reporting. In exchange it offers simple composeable Parsers and ergonomic Parser construction. Grammars will be implemented in their own crates (see unsynn-rust).
It is primarly intended use is when one wants to create proc macros for rust that define their own grammar or need only sparse rust parsers.
Example
# use unsynn::*;
let mut token_iter = quote::quote!{ foo ( bar, baz, barf ) }.into_iter();
// Composition
let ast =
Cons::<Ident, ParenthesisGroupContaining::<CommaDelimitedVec<Ident>>>
::parse(&mut token_iter).unwrap();
// The same defining a custom type, the macro will generate the `Parser` and `ToToken` impls.
unsynn!{
struct IdentThenParenthesisedIdents {
ident: Ident,
pidents: ParenthesisGroupContaining::<CommaDelimitedVec<Ident>>,
}
}
let mut token_iter = quote::quote!{ foo ( bar, baz, barf ) }.into_iter();
let ast = IdentThenParenthesisedIdents::parse(&mut token_iter).unwrap();
Features
By defaut unsynn is very lean and does not include extra features. The only thing that are
always present are the Parser
, Parse
and ToTokens
traits. The following features
enable extra traits:
-
impl_debug
AddsDebug
implementations to generic unsynn types. -
impl_display
AddsDisplay
implementations to generic unsynn types.
Note that Display
can't be implemented for some std types (eg. Option
). Further
Display
may sometimes be surprising since we do not have rules how to pretty-print tokens
(eg. spaces around Delimiters)
Dependencies
~83KB