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authorNadrieril2019-03-03 12:00:36 +0100
committerNadrieril2019-03-03 14:49:14 +0100
commit029d126ec06523f94fcf29e3a3b58bd8f7e2c83e (patch)
tree47427240a6f5238af0b601cb192532eb5e0be5e0 /dhall
parentf29f8e61adb359d12105fcc87a53137416519638 (diff)
Refactor parser using nom-like macros
Diffstat (limited to '')
-rw-r--r--dhall/src/parser.rs368
1 files changed, 228 insertions, 140 deletions
diff --git a/dhall/src/parser.rs b/dhall/src/parser.rs
index 21429b0..bb438f5 100644
--- a/dhall/src/parser.rs
+++ b/dhall/src/parser.rs
@@ -25,188 +25,276 @@ pub fn custom_parse_error(pair: &Pair<Rule>, msg: String) -> ParseError {
}
-macro_rules! parse_aux {
+macro_rules! match_children {
// Normal pattern
- (0, $inner:expr, $x:ident : $ty:ident $($rest:tt)*) => {
- let $x = concat_idents!(parse_, $ty)($inner.next().unwrap())?;
- parse_aux!(0, $inner $($rest)*);
+ (@0, $pairs:expr, $x:ident : $ty:ident $($rest:tt)*) => {
+ let $x = concat_idents!($ty)($pairs.next().unwrap())?;
+ match_children!(@0, $pairs $($rest)*);
};
// Normal pattern after a variable length one: declare reversed and take from the end
- ($w:expr, $inner:expr, $x:ident : $ty:ident $($rest:tt)*) => {
- parse_aux!($w, $inner $($rest)*);
- let $x = concat_idents!(parse_, $ty)($inner.next_back().unwrap())?;
+ (@$w:expr, $pairs:expr, $x:ident : $ty:ident $($rest:tt)*) => {
+ match_children!(@$w, $pairs $($rest)*);
+ let $x = concat_idents!($ty)($pairs.next_back().unwrap())?;
};
// Optional pattern
- (0, $inner:expr, $x:ident? : $ty:ident $($rest:tt)*) => {
- parse_aux!(1, $inner $($rest)*);
- let $x = $inner.next().map(concat_idents!(parse_, $ty)).transpose()?;
- $inner.next().ok_or(()).expect_err("Some parsed values remain unused");
+ (@0, $pairs:expr, $x:ident? : $ty:ident $($rest:tt)*) => {
+ match_children!(@1, $pairs $($rest)*);
+ let $x = $pairs.next().map(concat_idents!($ty)).transpose()?;
+ $pairs.next().ok_or(()).expect_err("Some parsed values remain unused");
};
// Everything else pattern
- (0, $inner:expr, $x:ident* : $ty:ident $($rest:tt)*) => {
- parse_aux!(2, $inner $($rest)*);
+ (@0, $pairs:expr, $x:ident* : $ty:ident $($rest:tt)*) => {
+ match_children!(@2, $pairs $($rest)*);
#[allow(unused_mut)]
- let mut $x = $inner.map(concat_idents!(parse_, $ty));
+ let mut $x = $pairs.map(concat_idents!($ty));
};
// Check no elements remain
- (0, $inner:expr) => {
- $inner.next().ok_or(()).expect_err("Some parsed values remain unused");
+ (@0, $pairs:expr) => {
+ $pairs.next().ok_or(()).expect_err("Some parsed values remain unused");
+ };
+ (@$_:expr, $pairs:expr) => {};
+
+ // Entrypoints
+ (@pairs; $pairs:expr; ($($args:tt)*) => $body:expr) => {
+ {
+ match_children!(@0, $pairs, $($args)*);
+ Ok($body)
+ }
+ };
+ ($pair:expr; $($rest:tt)*) => {
+ {
+ #[allow(unused_mut)]
+ let mut pairs = $pair.into_inner();
+ match_children!(@pairs; pairs; $($rest)*)
+ }
};
- ($_:expr, $inner:expr) => {};
}
-macro_rules! parse {
- ($pair:expr; ($($args:tt)*) => $body:expr) => {
+macro_rules! with_captured_str {
+ ($pair:expr; $x:ident; $body:expr) => {
{
#[allow(unused_mut)]
- let mut inner = $pair.into_inner();
- parse_aux!(0, inner, $($args)*);
+ let mut $x = $pair.as_str();
Ok($body)
}
};
}
-
-fn parse_binop<'a, F>(pair: Pair<'a, Rule>, mut f: F) -> ParseResult<BoxExpr<'a>>
-where F: FnMut(BoxExpr<'a>, BoxExpr<'a>) -> ParsedExpr<'a> {
- parse!(pair; (first: expression, rest*: expression) => {
- rest.fold_results(first, |acc, e| bx(f(acc, e)))?
- })
+macro_rules! with_raw_pair {
+ ($pair:expr; $x:ident; $body:expr) => {
+ {
+ #[allow(unused_mut)]
+ let mut $x = $pair;
+ Ok($body)
+ }
+ };
}
-fn skip_expr(pair: Pair<Rule>) -> ParseResult<BoxExpr> {
- parse!(pair; (expr: expression) => {
- expr
- })
+macro_rules! map {
+ ($pair:expr; $ty:ident; $f:expr) => {
+ {
+ let x = $ty($pair)?;
+ Ok($f(x))
+ }
+ };
}
-fn parse_str(pair: Pair<Rule>) -> ParseResult<&str> {
- Ok(pair.as_str().trim())
+macro_rules! plain_value {
+ ($_pair:expr; $body:expr) => {
+ Ok($body)
+ };
}
-fn parse_natural(pair: Pair<Rule>) -> ParseResult<usize> {
- parse_str(pair.clone())?
- .parse()
- .map_err(|e: std::num::ParseIntError| custom_parse_error(&pair, format!("{}", e)))
+macro_rules! with_rule {
+ ($pair:expr; $x:ident; $submac:ident!( $($args:tt)* )) => {
+ {
+ #[allow(unused_mut)]
+ let mut $x = $pair.as_rule();
+ $submac!($pair; $($args)*)
+ }
+ };
}
-fn parse_integer(pair: Pair<Rule>) -> ParseResult<isize> {
- parse_str(pair.clone())?
- .parse()
- .map_err(|e: std::num::ParseIntError| custom_parse_error(&pair, format!("{}", e)))
+macro_rules! match_rule {
+ ($pair:expr; $($pat:pat => $submac:ident!( $($args:tt)* ),)*) => {
+ #[allow(unreachable_patterns)]
+ match $pair.as_rule() {
+ $(
+ $pat => $submac!($pair; $($args)*),
+ )*
+ r => Err(custom_parse_error(&$pair, format!("Unexpected {:?}", r))),
+ }
+ };
}
-fn parse_letbinding(pair: Pair<Rule>) -> ParseResult<(&str, Option<BoxExpr>, BoxExpr)> {
- parse!(pair; (name: str, annot?: expression, expr: expression) => {
- (name, annot, expr)
- })
+macro_rules! named {
+ ($name:ident<$o:ty>; $submac:ident!( $($args:tt)* )) => (
+ #[allow(unused_variables)]
+ fn $name(pair: Pair<Rule>) -> ParseResult<$o> {
+ $submac!(pair; $($args)*)
+ }
+ );
}
-fn parse_record_entry(pair: Pair<Rule>) -> ParseResult<(&str, BoxExpr)> {
- parse!(pair; (name: str, expr: expression) => { (name, expr) })
-}
-fn parse_partial_record_entries(pair: Pair<Rule>) -> ParseResult<(Rule, BoxExpr, BTreeMap<&str, ParsedExpr>)> {
- let rule = pair.as_rule();
- parse!(pair; (expr: expression, entries*: record_entry) => {
- let mut map: BTreeMap<&str, ParsedExpr> = BTreeMap::new();
- for entry in entries {
- let (n, e) = entry?;
- map.insert(n, *e);
- }
- (rule, expr, map)
+// TODO: remove when stack overflow fixed
+fn parse_binop<'a, F>(pair: Pair<'a, Rule>, mut f: F) -> ParseResult<BoxExpr<'a>>
+where F: FnMut(BoxExpr<'a>, BoxExpr<'a>) -> ParsedExpr<'a> {
+ match_children!(pair; (first: expression, rest*: expression) => {
+ rest.fold_results(first, |acc, e| bx(f(acc, e)))?
})
}
+macro_rules! binop {
+ ($pair:expr; $f:expr) => {
+ parse_binop($pair, $f)
+ };
+}
+// macro_rules! binop {
+// ($pair:expr; $f:expr) => {
+// {
+// let f = $f;
+// match_children!($pair; (first: expression, rest*: expression) => {
+// rest.fold_results(first, |acc, e| bx(f(acc, e)))?
+// })
+// }
+// };
+// }
+
+// TODO: remove when stack overflow fixed
+named!(single_expr<BoxExpr>;
+ match_children!((expr: expression) => expr)
+);
+macro_rules! single {
+ ($pair:expr; expression) => {
+ single_expr($pair)
+ };
+ ($pair:expr; $ty:ident) => {
+ match_children!($pair; (expr: $ty) => expr)
+ };
+}
-// TODO: handle stack manually
-fn parse_expression(pair: Pair<Rule>) -> ParseResult<BoxExpr> {
- match pair.as_rule() {
- Rule::natural_literal_raw => Ok(bx(Expr::NaturalLit(parse_natural(pair)?))),
- Rule::integer_literal_raw => Ok(bx(Expr::IntegerLit(parse_integer(pair)?))),
-
- Rule::identifier_raw =>
- parse!(pair; (name: str, idx?: natural) => {
- match Builtin::parse(name) {
- Some(b) => bx(Expr::Builtin(b)),
- None => match name {
- "True" => bx(Expr::BoolLit(true)),
- "False" => bx(Expr::BoolLit(false)),
- "Type" => bx(Expr::Const(Const::Type)),
- "Kind" => bx(Expr::Const(Const::Kind)),
- name => bx(Expr::Var(V(name, idx.unwrap_or(0)))),
- }
- }
- }),
-
- Rule::lambda_expression =>
- parse!(pair; (label: str, typ: expression, body: expression) => {
- bx(Expr::Lam(label, typ, body))
- }),
-
- Rule::ifthenelse_expression =>
- parse!(pair; (cond: expression, left: expression, right: expression) => {
- bx(Expr::BoolIf(cond, left, right))
- }),
-
- Rule::let_expression =>
- parse!(pair; (bindings*: letbinding, final_expr: expression) => {
- bindings.fold_results(final_expr, |acc, x| bx(Expr::Let(x.0, x.1, x.2, acc)))?
- }),
-
- Rule::forall_expression =>
- parse!(pair; (label: str, typ: expression, body: expression) => {
- bx(Expr::Pi(label, typ, body))
- }),
-
- Rule::annotated_expression => { parse_binop(pair, Expr::Annot) }
- Rule::import_alt_expression => { skip_expr(pair) }
- Rule::or_expression => { parse_binop(pair, Expr::BoolOr) }
- Rule::plus_expression => { parse_binop(pair, Expr::NaturalPlus) }
- Rule::text_append_expression => { parse_binop(pair, Expr::TextAppend) }
- Rule::list_append_expression => { skip_expr(pair) }
- Rule::and_expression => { parse_binop(pair, Expr::BoolAnd) }
- Rule::combine_expression => { skip_expr(pair) }
- Rule::prefer_expression => { skip_expr(pair) }
- Rule::combine_types_expression => { skip_expr(pair) }
- Rule::times_expression => { parse_binop(pair, Expr::NaturalTimes) }
- Rule::equal_expression => { parse_binop(pair, Expr::BoolEQ) }
- Rule::not_equal_expression => { parse_binop(pair, Expr::BoolNE) }
- Rule::application_expression => { parse_binop(pair, Expr::App) }
-
- Rule::selector_expression_raw =>
- parse!(pair; (first: expression, rest*: str) => {
- rest.fold_results(first, |acc, e| bx(Expr::Field(acc, e)))?
- }),
-
- Rule::empty_record_type => Ok(bx(Expr::Record(BTreeMap::new()))),
- Rule::empty_record_literal => Ok(bx(Expr::RecordLit(BTreeMap::new()))),
- Rule::non_empty_record_type_or_literal =>
- parse!(pair; (first_label: str, rest: partial_record_entries) => {
- let (rule, first_expr, mut map) = rest;
- map.insert(first_label, *first_expr);
- match rule {
- Rule::non_empty_record_type => bx(Expr::Record(map)),
- Rule::non_empty_record_literal => bx(Expr::RecordLit(map)),
- _ => unreachable!()
- }
- }),
+named!(eoi<()>; plain_value!(()));
+
+named!(str<&str>; with_captured_str!(s; { s.trim() }));
+
+named!(natural<usize>; with_raw_pair!(pair; {
+ pair.as_str().trim()
+ .parse()
+ .map_err(|e: std::num::ParseIntError| custom_parse_error(&pair, format!("{}", e)))?
+}));
+named!(integer<isize>; with_raw_pair!(pair; {
+ pair.as_str().trim()
+ .parse()
+ .map_err(|e: std::num::ParseIntError| custom_parse_error(&pair, format!("{}", e)))?
+}));
+
+named!(letbinding<(&str, Option<BoxExpr>, BoxExpr)>;
+ match_children!((name: str, annot?: expression, expr: expression) => (name, annot, expr))
+);
+
+named!(record_entry<(&str, BoxExpr)>;
+ match_children!((name: str, expr: expression) => (name, expr))
+);
+
+named!(partial_record_entries<(Rule, BoxExpr, BTreeMap<&str, ParsedExpr>)>;
+ with_rule!(rule;
+ match_children!((expr: expression, entries*: record_entry) => {
+ let mut map: BTreeMap<&str, ParsedExpr> = BTreeMap::new();
+ for entry in entries {
+ let (n, e) = entry?;
+ map.insert(n, *e);
+ }
+ (rule, expr, map)
+ })
+ )
+);
- _ => {
+// TODO: handle stack manually
+named!(expression<BoxExpr>; match_rule!(
+ Rule::natural_literal_raw => map!(natural; |n| bx(Expr::NaturalLit(n))),
+ Rule::integer_literal_raw => map!(integer; |n| bx(Expr::IntegerLit(n))),
+
+ Rule::identifier_raw =>
+ match_children!((name: str, idx?: natural) => {
+ match Builtin::parse(name) {
+ Some(b) => bx(Expr::Builtin(b)),
+ None => match name {
+ "True" => bx(Expr::BoolLit(true)),
+ "False" => bx(Expr::BoolLit(false)),
+ "Type" => bx(Expr::Const(Const::Type)),
+ "Kind" => bx(Expr::Const(Const::Kind)),
+ name => bx(Expr::Var(V(name, idx.unwrap_or(0)))),
+ }
+ }
+ }),
+
+ Rule::lambda_expression =>
+ match_children!((label: str, typ: expression, body: expression) => {
+ bx(Expr::Lam(label, typ, body))
+ }),
+
+ Rule::ifthenelse_expression =>
+ match_children!((cond: expression, left: expression, right: expression) => {
+ bx(Expr::BoolIf(cond, left, right))
+ }),
+
+ Rule::let_expression =>
+ match_children!((bindings*: letbinding, final_expr: expression) => {
+ bindings.fold_results(final_expr, |acc, x| bx(Expr::Let(x.0, x.1, x.2, acc)))?
+ }),
+
+ // Rule::forall_expression =>
+ // match_children!((label: str, typ: expression, body: expression) => {
+ // bx(Expr::Pi(label, typ, body))
+ // }),
+
+ Rule::annotated_expression => binop!(Expr::Annot),
+ Rule::import_alt_expression => single!(expression),
+ Rule::or_expression => binop!(Expr::BoolOr),
+ Rule::plus_expression => binop!(Expr::NaturalPlus),
+ Rule::text_append_expression => binop!(Expr::TextAppend),
+ Rule::list_append_expression => single!(expression),
+ Rule::and_expression => binop!(Expr::BoolAnd),
+ Rule::combine_expression => single!(expression),
+ Rule::prefer_expression => single!(expression),
+ Rule::combine_types_expression => single!(expression),
+ Rule::times_expression => binop!(Expr::NaturalTimes),
+ Rule::equal_expression => binop!(Expr::BoolEQ),
+ Rule::not_equal_expression => binop!(Expr::BoolNE),
+ Rule::application_expression => binop!(Expr::App),
+
+ Rule::selector_expression_raw =>
+ match_children!((first: expression, rest*: str) => {
+ rest.fold_results(first, |acc, e| bx(Expr::Field(acc, e)))?
+ }),
+
+ Rule::empty_record_type => plain_value!(bx(Expr::Record(BTreeMap::new()))),
+ Rule::empty_record_literal => plain_value!(bx(Expr::RecordLit(BTreeMap::new()))),
+ Rule::non_empty_record_type_or_literal =>
+ match_children!((first_label: str, rest: partial_record_entries) => {
+ let (rule, first_expr, mut map) = rest;
+ map.insert(first_label, *first_expr);
+ match rule {
+ Rule::non_empty_record_type => bx(Expr::Record(map)),
+ Rule::non_empty_record_literal => bx(Expr::RecordLit(map)),
+ _ => unreachable!()
+ }
+ }),
+
+ _ => with_rule!(rule;
+ match_children!((exprs*: expression) => {
// panic!();
- let rulename = format!("{:?}", pair.as_rule());
- parse!(pair; (exprs*: expression) => {
- bx(Expr::FailedParse(rulename, exprs.map_results(|x| *x).collect::<ParseResult<_>>()?))
- })
- }
- }
-}
+ let rulename = format!("{:?}", rule);
+ bx(Expr::FailedParse(rulename, exprs.map_results(|x| *x).collect::<ParseResult<_>>()?))
+ })
+ ),
+));
pub fn parse_expr_pest(s: &str) -> ParseResult<BoxExpr> {
- let parsed_expr = DhallParser::parse(Rule::final_expression, s)?.next().unwrap();
-
- parse_expression(parsed_expr)
+ let mut pairs = DhallParser::parse(Rule::final_expression, s)?;
+ match_children!(@pairs; pairs; (e: expression, _eoi: eoi) => e)
}