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use crate::err::*;
use crate::iter::*;
use crate::ptrait::*;
use std::fmt::Debug;
#[derive(Clone)]
pub struct Maybe<A: Parser> {
p: A,
}
impl<A> Parser for Maybe<A>
where
A: Parser,
{
type Out = Option<A::Out>;
fn parse<'a>(&self, i: &LCChars<'a>) -> ParseRes<'a, Self::Out> {
match self.p.parse(i) {
Ok((ir, v, ex)) => Ok((ir, Some(v), ex)),
Err(e) => Ok((i.clone(), None, Some(e))),
}
}
}
pub fn maybe<P: Parser>(p: P) -> Maybe<P> {
Maybe { p }
}
pub struct Exists<P: Parser> {
p: P,
}
impl<P: Parser> Parser for Exists<P> {
type Out = bool;
fn parse<'a>(&self, it: &LCChars<'a>) -> ParseRes<'a, bool> {
match self.p.parse(it) {
Ok((nit, _, e)) => Ok((nit, true, e)),
Err(e) => Ok((it.clone(), false, Some(e))),
}
}
}
pub fn exists<P: Parser>(p: P) -> Exists<P> {
Exists { p }
}
#[derive(Clone)]
pub struct Wrap<A, B> {
a: A,
b: B,
}
impl<A, B> Parser for Wrap<A, B>
where
A: Parser,
B: Parser,
{
type Out = B::Out;
fn parse<'a>(&self, i: &LCChars<'a>) -> ParseRes<'a, Self::Out> {
let (i, _, c1) = self.a.parse(i)?;
let (i, res, c2) = self.b.parse(&i).map_err(|e| e.join_op(c1))?;
let (n, _, c3) = self.a.parse(&i).map_err(|e| e.join_op(c2))?;
Ok((n, res, c3))
}
}
pub fn wrap<A, B>(a: A, b: B) -> Wrap<A, B>
where
A: Parser,
B: Parser,
{
Wrap { a, b }
}
impl<P: Parser<Out = V>, V: Debug> Parser for FailOn<P> {
type Out = ();
fn parse<'a>(&self, it: &LCChars<'a>) -> ParseRes<'a, ()> {
match self.p.parse(it) {
Ok((_, _, _)) => it.err_rp(self),
Err(_) => Ok((it.clone(), (), None)),
}
}
fn expected(&self) -> Expected {
Expected::except(self.p.expected())
}
}
pub struct FailOn<P: Parser> {
p: P,
}
pub fn fail_on<P: Parser>(p: P) -> FailOn<P> {
FailOn { p }
}
#[derive(PartialEq, Debug, Clone)]
pub struct PDebugger<P: Parser> {
p: P,
s: &'static str,
}
pub fn debug<P: Parser>(p: P, s: &'static str) -> PDebugger<P> {
PDebugger { p, s }
}
impl<P: Parser> Parser for PDebugger<P> {
type Out = P::Out;
fn parse<'a>(&self, it: &LCChars<'a>) -> ParseRes<'a, Self::Out> {
println!("DebuggerPre - {}", self.s);
let r = self.p.parse(it);
match &r {
Ok((nit, _, _)) => {
let s = match (it.index(), nit.index()) {
(Some(st), Some(f)) => &it.as_str()[..f - st],
_ => it.as_str(),
};
println!("Success - {}, \"{}\"", self.s, s);
}
Err(_) => println!("Fail - {}", self.s),
};
r
}
}