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feat: complex postfix operators
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- ternary operator
- function call
- index
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@39555
39555 committed Nov 17, 2024
1 parent 03f919e commit c3e18a8
Showing 1 changed file with 66 additions and 51 deletions.
117 changes: 66 additions & 51 deletions examples/pratt/parser.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
use winnow::combinator::{cut_err, empty, fail, peek, trace};
use winnow::combinator::{cut_err, empty, fail, opt, peek, preceded, separated_pair, trace};
use winnow::prelude::*;
use winnow::stream::AsChar as _;
use winnow::token::{any, take, take_while};
Expand Down Expand Up @@ -49,7 +49,7 @@ pub(crate) enum Expr {

// A parenthesized expression.
Paren(Box<Expr>),
FunctionCall(Box<Expr>, Box<Expr>),
FunctionCall(Box<Expr>, Option<Box<Expr>>),
Ternary(Box<Expr>, Box<Expr>, Box<Expr>),
// foo[...]
Index(Box<Expr>, Box<Expr>),
Expand Down Expand Up @@ -85,41 +85,43 @@ pub(crate) fn pratt_parser(i: &mut &str) -> PResult<Expr> {
delimited(multispace0, dispatch! {any;
'+' => alt((
// ++
'+'.value((18, (&|a| Expr::PreIncr(Box::new(a))) as _)),
empty.value((18, (&|a| a) as _))
'+'.value((18, (|_: &mut _, a| Expr::PreIncr(Box::new(a))) as _)),
empty.value((18, (|_: &mut _, a| a) as _))
)),
'-' => alt((
// --
'-'.value((18, (&|a| Expr::PreDecr(Box::new(a))) as _)),
empty.value((18, (&|a| Expr::Neg(Box::new(a))) as _))
'-'.value((18, (|_: &mut _, a| Expr::PreDecr(Box::new(a))) as _)),
empty.value((18, (|_: &mut _, a| Expr::Neg(Box::new(a))) as _))
)),
'&' => empty.value((18, (&|a| Expr::Addr(Box::new(a))) as _)),
'*' => empty.value((18, (&|a| Expr::Deref(Box::new(a))) as _)),
'!' => empty.value((18, (&|a| Expr::Not(Box::new(a))) as _)),
'&' => empty.value((18, (|_: &mut _, a| Expr::Addr(Box::new(a))) as _)),
'*' => empty.value((18, (|_: &mut _, a| Expr::Deref(Box::new(a))) as _)),
'!' => empty.value((18, (|_: &mut _, a| Expr::Not(Box::new(a))) as _)),
_ => fail
}
, multispace0)),
trace(
"postfix",
delimited(multispace0, alt((
dispatch! {any;
'!' => empty.value((20, (&|a| Expr::Fac(Box::new(a))) as _)),
// '?' => |i: &mut &str| {
// let (left, right) = separated_pair(pratt_parser, delimited(multispace0, ':', multispace0), pratt_parser).parse_next(i)?;
// Ok((3, (&|a: Expr| Expr::Ternary(Box::new(a), left.into(), right.into())) as _))
// },
// TODO: function call
// '(' => empty.value((3, ),
// check function call
// ')' => empty.value((3, ),
// index
// '[' => empty.value((70, 71, (&|a| terminated(pratt_parser, ']') )),
'!' => empty.value((20, (|_: &mut _, a| Expr::Fac(Box::new(a))) as _)),
'?' => empty.value((3, (|i: &mut &str, cond| {
let (left, right) = preceded(multispace0, cut_err(separated_pair(pratt_parser, delimited(multispace0, ':', multispace0), pratt_parser))).parse_next(i).unwrap();
Expr::Ternary(Box::new(cond), Box::new(left), Box::new(right))
}) as _)),
'[' => empty.value((20, (|i: &mut &str, a| {
let index = delimited(multispace0, pratt_parser, (multispace0, cut_err(']'), multispace0)).parse_next(i).unwrap();
Expr::Index(Box::new(a), Box::new(index))
}) as _)),
'(' => empty.value((20, (|i: &mut &str, a| {
let args = delimited(multispace0, opt(pratt_parser), (multispace0, cut_err(')'), multispace0)).parse_next(i).unwrap();
Expr::FunctionCall(Box::new(a), args.map(Box::new))
}) as _)),
_ => fail,
},

dispatch! {take(2usize);
"++" => empty.value((19, (&|a| Expr::PostIncr(Box::new(a))) as _)),
"--" => empty.value((19, (&|a| Expr::PostDecr(Box::new(a))) as _)),
"++" => empty.value((19, (|_: &mut _, a| Expr::PostIncr(Box::new(a))) as _)),
"--" => empty.value((19, (|_: &mut _, a| Expr::PostDecr(Box::new(a))) as _)),
_ => fail,
},
)), multispace0),
Expand All @@ -128,54 +130,54 @@ pub(crate) fn pratt_parser(i: &mut &str) -> PResult<Expr> {
"infix",
alt((
dispatch! {any;
'*' => empty.value((16, 17, (&|a, b| Expr::Mul(Box::new(a), Box::new(b))) as _)),
'/' => empty.value((16, 17, (&|a, b| Expr::Div(Box::new(a), Box::new(b))) as _)),
'%' => empty.value((16, 17, (&|a, b| Expr::Rem(Box::new(a), Box::new(b))) as _)),
'*' => empty.value((16, 17, (|_: &mut _, a, b| Expr::Mul(Box::new(a), Box::new(b))) as _)),
'/' => empty.value((16, 17, (|_: &mut _, a, b| Expr::Div(Box::new(a), Box::new(b))) as _)),
'%' => empty.value((16, 17, (|_: &mut _, a, b| Expr::Rem(Box::new(a), Box::new(b))) as _)),

'+' => empty.value((14, 15, (&|a, b| Expr::Add(Box::new(a), Box::new(b))) as _)),
'+' => empty.value((14, 15, (|_: &mut _, a, b| Expr::Add(Box::new(a), Box::new(b))) as _)),
'-' => alt((
dispatch!{take(2usize);
"ne" => empty.value((10, 11, (&|a, b| Expr::NotEq(Box::new(a), Box::new(b))) as _)),
"eq" => empty.value((10, 11, (&|a, b| Expr::Eq(Box::new(a), Box::new(b))) as _)),
"gt" => empty.value((12, 13, (&|a, b| Expr::Greater(Box::new(a), Box::new(b))) as _)),
"ge" => empty.value((12, 13, (&|a, b| Expr::GreaterEqual(Box::new(a), Box::new(b))) as _)),
"lt" => empty.value((12, 13, (&|a, b| Expr::Less(Box::new(a), Box::new(b))) as _)),
"le" => empty.value((12, 13, (&|a, b| Expr::LessEqual(Box::new(a), Box::new(b))) as _)),
"ne" => empty.value((10, 11, (|_: &mut _, a, b| Expr::NotEq(Box::new(a), Box::new(b))) as _)),
"eq" => empty.value((10, 11, (|_: &mut _, a, b| Expr::Eq(Box::new(a), Box::new(b))) as _)),
"gt" => empty.value((12, 13, (|_: &mut _, a, b| Expr::Greater(Box::new(a), Box::new(b))) as _)),
"ge" => empty.value((12, 13, (|_: &mut _, a, b| Expr::GreaterEqual(Box::new(a), Box::new(b))) as _)),
"lt" => empty.value((12, 13, (|_: &mut _, a, b| Expr::Less(Box::new(a), Box::new(b))) as _)),
"le" => empty.value((12, 13, (|_: &mut _, a, b| Expr::LessEqual(Box::new(a), Box::new(b))) as _)),
_ => fail
},
'>'.value((19, 20, (&|a, b| Expr::ArrowOp(Box::new(a), Box::new(b))) as _)),
empty.value((14, 15, (&|a, b| Expr::Sub(Box::new(a), Box::new(b))) as _))
'>'.value((19, 20, (|_: &mut _, a, b| Expr::ArrowOp(Box::new(a), Box::new(b))) as _)),
empty.value((14, 15, (|_: &mut _, a, b| Expr::Sub(Box::new(a), Box::new(b))) as _))
)),
'.' => empty.value((19, 20, (&|a, b| Expr::Dot(Box::new(a), Box::new(b))) as _)),
'.' => empty.value((19, 20, (|_: &mut _, a, b| Expr::Dot(Box::new(a), Box::new(b))) as _)),
'&' => alt((
// &&
"&".value((6, 7, (&|a, b| Expr::And(Box::new(a), Box::new(b))) as _) ),
"&".value((6, 7, (|_: &mut _, a, b| Expr::And(Box::new(a), Box::new(b))) as _) ),

empty.value((12, 13, (&|a, b| Expr::BitAnd(Box::new(a), Box::new(b))) as _)),
empty.value((12, 13, (|_: &mut _, a, b| Expr::BitAnd(Box::new(a), Box::new(b))) as _)),
)),
'^' => empty.value((8, 9, (&|a, b| Expr::BitXor(Box::new(a), Box::new(b))) as _)),
'^' => empty.value((8, 9, (|_: &mut _, a, b| Expr::BitXor(Box::new(a), Box::new(b))) as _)),
'=' => alt((
// ==
"=".value((10, 11, (&|a, b| Expr::Eq(Box::new(a), Box::new(b))) as _)),
empty.value((1, 2, (&|a, b| Expr::Assign(Box::new(a), Box::new(b))) as _))
"=".value((10, 11, (|_: &mut _, a, b| Expr::Eq(Box::new(a), Box::new(b))) as _)),
empty.value((1, 2, (|_: &mut _, a, b| Expr::Assign(Box::new(a), Box::new(b))) as _))
)),

'>' => alt((
// >=
"=".value((12, 13, (&|a, b| Expr::GreaterEqual(Box::new(a), Box::new(b))) as _)),
empty.value((12, 13, (&|a, b| Expr::Greater(Box::new(a), Box::new(b))) as _))
"=".value((12, 13, (|_: &mut _, a, b| Expr::GreaterEqual(Box::new(a), Box::new(b))) as _)),
empty.value((12, 13, (|_: &mut _, a, b| Expr::Greater(Box::new(a), Box::new(b))) as _))
)),
'<' => alt((
// <=
"=".value((12, 13, (&|a, b| Expr::LessEqual(Box::new(a), Box::new(b))) as _)),
empty.value((12, 13, (&|a, b| Expr::Less(Box::new(a), Box::new(b))) as _))
"=".value((12, 13, (|_: &mut _, a, b| Expr::LessEqual(Box::new(a), Box::new(b))) as _)),
empty.value((12, 13, (|_: &mut _, a, b| Expr::Less(Box::new(a), Box::new(b))) as _))
)),
',' => empty.value((0, 1, (&|a, b| Expr::Comma(Box::new(a), Box::new(b))) as _)),
',' => empty.value((0, 1, (|_: &mut _, a, b| Expr::Comma(Box::new(a), Box::new(b))) as _)),
_ => fail
},
dispatch! {take(2usize);
"!=" => empty.value((10, 11, (&|a, b| Expr::NotEq(Box::new(a), Box::new(b))) as _)),
"||" => empty.value((4, 5, (&|a, b| Expr::Or(Box::new(a), Box::new(b))) as _)),
"!=" => empty.value((10, 11, (|_: &mut _, a, b| Expr::NotEq(Box::new(a), Box::new(b))) as _)),
"||" => empty.value((4, 5, (|_: &mut _, a, b| Expr::Or(Box::new(a), Box::new(b))) as _)),
_ => fail
},
)),
Expand Down Expand Up @@ -234,7 +236,14 @@ impl Expr {
Self::Assign(a, b) => binary_fmt!(a, b, "ASSIGN"),
Self::ArrowOp(a, b) => binary_fmt!(a, b, "ARROW"),
Self::Dot(a, b) => binary_fmt!(a, b, "ARROW"),
Self::FunctionCall(a, b) => binary_fmt!(a, b, "CALL"),
Self::FunctionCall(a, b) => {
writeln!(f, "CALL")?;
a.fmt_ast_with_indent(indent + 1, f)?;
if let Some(b) = b {
b.fmt_ast_with_indent(indent + 1, f)?;
}
Ok(())
}
Self::Add(a, b) => binary_fmt!(a, b, "ADD"),
Self::Sub(a, b) => binary_fmt!(a, b, "SUB"),
Self::Mul(a, b) => binary_fmt!(a, b, "MUL"),
Expand Down Expand Up @@ -285,7 +294,11 @@ impl Expr {
Self::Assign(a, b) => binary!("=", a, b),
Self::FunctionCall(a, b) => {
a.fmt_delimited(f)?;
b.fmt_delimited(f)?;
if let Some(b) = b {
b.fmt_delimited(f)?;
} else {
write!(f, "()")?;
}
}
Self::ArrowOp(a, b) => binary!("->", a, b),
Self::Dot(a, b) => binary!(".", a, b),
Expand Down Expand Up @@ -323,9 +336,11 @@ impl Expr {
write!(f, ")")?;
}
Self::Ternary(cond, a, b) => {
write!(f, "?")?;
write!(f, "? ")?;
cond.fmt_delimited(f)?;
write!(f, " ")?;
a.fmt_delimited(f)?;
write!(f, " ")?;
b.fmt_delimited(f)?;
}
_ => unreachable!(),
Expand Down Expand Up @@ -354,7 +369,7 @@ mod test {
// .parse("+- --!&**foo! + 3 * 4 - bar ^ e")
// .parse("foo(a + b)")
// .parse("1 + 2 * *4^7! + 6")
.parse("a , b, c")
.parse("foo(1 + 2 + 3) + bar() ? 1 : 2")
.unwrap();
println!("{r}");
}
Expand Down

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