#[doc(hidden)]
pub extern crate log;
#[doc(hidden)]
pub extern crate pest;
extern crate void;
#[doc(inline)]
pub use void::Void;
use {
pest::{
iterators::{Pair, Pairs},
RuleType,
},
std::marker::PhantomData,
};
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
pub enum ConversionError<FatalError> {
NoMatch,
Malformed(FatalError),
Extraneous { current_node: &'static str },
}
use std::fmt;
impl<FatalError> fmt::Display for ConversionError<FatalError>
where
FatalError: fmt::Display,
{
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
ConversionError::NoMatch => write!(f, "Rule did not match, failed to convert node"),
ConversionError::Malformed(fatalerror) => write!(f, "Malformed node: {}", fatalerror),
ConversionError::Extraneous { current_node, .. } => write!(
f,
"when converting {}, found extraneous tokens",
current_node
),
}
}
}
use std::error;
impl<FatalError> error::Error for ConversionError<FatalError>
where
FatalError: error::Error + 'static,
{
fn source(&self) -> Option<&(dyn error::Error + 'static)> {
match self {
ConversionError::NoMatch => None,
ConversionError::Extraneous { .. } => None,
ConversionError::Malformed(ref fatalerror) => Some(fatalerror),
}
}
}
pub trait FromPest<'pest>: Sized {
type Rule: RuleType;
type FatalError;
fn from_pest(
pest: &mut Pairs<'pest, Self::Rule>,
) -> Result<Self, ConversionError<Self::FatalError>>;
}
impl<'pest, Rule: RuleType, T: FromPest<'pest, Rule = Rule>> FromPest<'pest> for PhantomData<T> {
type Rule = Rule;
type FatalError = T::FatalError;
fn from_pest(pest: &mut Pairs<'pest, Rule>) -> Result<Self, ConversionError<T::FatalError>> {
T::from_pest(pest).map(|_| PhantomData)
}
}
impl<'pest, Rule: RuleType, T: FromPest<'pest, Rule = Rule>> FromPest<'pest> for Box<T> {
type Rule = Rule;
type FatalError = T::FatalError;
fn from_pest(pest: &mut Pairs<'pest, Rule>) -> Result<Self, ConversionError<T::FatalError>> {
T::from_pest(pest).map(Box::new)
}
}
impl<'pest, Rule: RuleType, T: FromPest<'pest, Rule = Rule>> FromPest<'pest> for Option<T> {
type Rule = Rule;
type FatalError = T::FatalError;
fn from_pest(pest: &mut Pairs<'pest, Rule>) -> Result<Self, ConversionError<T::FatalError>> {
match T::from_pest(pest) {
Err(ConversionError::NoMatch) => Ok(None),
result => result.map(Some),
}
}
}
impl<'pest, Rule: RuleType, T: FromPest<'pest, Rule = Rule>> FromPest<'pest> for Vec<T> {
type Rule = Rule;
type FatalError = T::FatalError;
fn from_pest(pest: &mut Pairs<'pest, Rule>) -> Result<Self, ConversionError<T::FatalError>> {
let mut acc = vec![];
loop {
match T::from_pest(pest) {
Ok(t) => acc.push(t),
Err(ConversionError::NoMatch) => break,
Err(error) => return Err(error),
}
}
Ok(acc)
}
}
impl<'pest, Rule: RuleType> FromPest<'pest> for Pair<'pest, Rule> {
type Rule = Rule;
type FatalError = Void;
fn from_pest(pest: &mut Pairs<'pest, Rule>) -> Result<Self, ConversionError<Void>> {
pest.next().ok_or(ConversionError::NoMatch)
}
}
macro_rules! impl_for_tuple {
() => {};
($ty1:ident $($ty:ident)*) => {
impl<'pest, $ty1, $($ty,)* Rule: RuleType, FatalError> FromPest<'pest> for ($ty1, $($ty),*)
where
$ty1: FromPest<'pest, Rule=Rule, FatalError=FatalError>,
$($ty: FromPest<'pest, Rule=Rule, FatalError=FatalError>,)*
{
type Rule = Rule;
type FatalError = FatalError;
fn from_pest(pest: &mut Pairs<'pest, Rule>)
-> Result<Self, ConversionError<FatalError>>
{
let mut clone = pest.clone();
let this = (
$ty1::from_pest(&mut clone)?,
$($ty::from_pest(&mut clone)?),*
);
*pest = clone;
Ok(this)
}
}
impl_for_tuple!($($ty)*);
};
}
impl_for_tuple!(A B C D);