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-rw-r--r--Cargo.lock5
-rw-r--r--Cargo.toml3
-rw-r--r--dhall_core/Cargo.toml1
-rw-r--r--dhall_core/src/parser.rs176
-rw-r--r--iter_patterns/Cargo.toml8
-rw-r--r--iter_patterns/src/lib.rs190
6 files changed, 252 insertions, 131 deletions
diff --git a/Cargo.lock b/Cargo.lock
index 6e218fb..fa37a5e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -82,6 +82,7 @@ name = "dhall_core"
version = "0.1.0"
dependencies = [
"dhall_parser 0.1.0",
+ "iter_patterns 0.1.0",
"itertools 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
"pest 2.1.0 (git+https://github.com/pest-parser/pest)",
"term-painter 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -144,6 +145,10 @@ version = "1.3.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
+name = "iter_patterns"
+version = "0.1.0"
+
+[[package]]
name = "itertools"
version = "0.8.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/Cargo.toml b/Cargo.toml
index 74388cb..c2c0fae 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,6 +5,9 @@ members = [
"abnf_to_pest",
"dhall",
"dhall_parser",
+ "dhall_core",
+ "dhall_generator",
+ "iter_patterns",
]
# # Parser is super slow when not optimized
diff --git a/dhall_core/Cargo.toml b/dhall_core/Cargo.toml
index 4010f4a..c3c417a 100644
--- a/dhall_core/Cargo.toml
+++ b/dhall_core/Cargo.toml
@@ -12,3 +12,4 @@ itertools = "0.8.0"
term-painter = "0.2.3"
pest = { git = "https://github.com/pest-parser/pest" }
dhall_parser = { path = "../dhall_parser" }
+iter_patterns = { path = "../iter_patterns" }
diff --git a/dhall_core/src/parser.rs b/dhall_core/src/parser.rs
index 6f84abe..45930d4 100644
--- a/dhall_core/src/parser.rs
+++ b/dhall_core/src/parser.rs
@@ -71,102 +71,11 @@ fn debug_pair(pair: Pair<Rule>) -> String {
s
}
-/* Macro to pattern-match iterators.
- * Returns `Result<_, IterMatchError<_>>`.
- *
- * Example:
- * ```
- * let vec = vec![1, 2, 3];
- *
- * match_iter!(vec.into_iter(); (x, y?, z) => {
- * // x: T
- * // y: Option<T>
- * // z: T
- * })
- *
- * // or
- * match_iter!(vec.into_iter(); (x, y, z*) => {
- * // x, y: T
- * // z: impl Iterator<T>
- * })
- * ```
- *
-*/
#[derive(Debug)]
enum IterMatchError<T> {
- NotEnoughItems,
- TooManyItems,
NoMatchFound,
Other(T), // Allow other macros to inject their own errors
}
-macro_rules! match_iter {
- // Everything else pattern
- (@match 0, $iter:expr, $x:ident* $($rest:tt)*) => {
- match_iter!(@match 2, $iter $($rest)*);
- #[allow(unused_mut)]
- let mut $x = $iter;
- };
- // Alias to use in macros
- (@match 0, $iter:expr, $x:ident?? $($rest:tt)*) => {
- match_iter!(@match 2, $iter $($rest)*);
- #[allow(unused_mut)]
- let mut $x = $iter;
- };
- // Optional pattern
- (@match 0, $iter:expr, $x:ident? $($rest:tt)*) => {
- match_iter!(@match 1, $iter $($rest)*);
- #[allow(unused_mut)]
- let mut $x = $iter.next();
- if $iter.next().is_some() {
- break Err(IterMatchError::TooManyItems);
- }
- };
- // Normal pattern
- (@match 0, $iter:expr, $x:ident $($rest:tt)*) => {
- #[allow(unused_mut)]
- let mut $x = match $iter.next() {
- Some(x) => x,
- None => break Err(IterMatchError::NotEnoughItems),
- };
- match_iter!(@match 0, $iter $($rest)*);
- };
- // Normal pattern after a variable length one: declare reversed and take from the end
- (@match $w:expr, $iter:expr, $x:ident $($rest:tt)*) => {
- match_iter!(@match $w, $iter $($rest)*);
- #[allow(unused_mut)]
- let mut $x = match $iter.next_back() {
- Some(x) => x,
- None => break Err(IterMatchError::NotEnoughItems),
- };
- };
-
- // Check no elements remain
- (@match 0, $iter:expr $(,)*) => {
- if $iter.next().is_some() {
- break Err(IterMatchError::TooManyItems);
- }
- };
- (@match $_:expr, $iter:expr) => {};
-
- (@panic; $($args:tt)*) => {
- {
- let ret: Result<_, IterMatchError<()>> = match_iter!($($args)*);
- ret.unwrap()
- }
- };
- ($iter:expr; ($($args:tt)*) => $body:expr) => {
- {
- #[allow(unused_mut)]
- let mut iter = $iter;
- // Not a real loop; used for error handling
- let ret: Result<_, IterMatchError<_>> = loop {
- match_iter!(@match 0, iter, $($args)*);
- break Ok($body);
- };
- ret
- }
- };
-}
/* Extends match_iter with typed matches. Takes a callback that determines
* when a capture matches.
@@ -200,21 +109,21 @@ macro_rules! match_iter_typed {
(@collect, ($($vars:tt)*), ($($args:tt)*), ($($acc:tt)*), ($x:ident : $ty:ident, $($rest:tt)*)) => {
match_iter_typed!(@collect, ($($vars)*), ($($args)*), ($($acc)*, $x), ($($rest)*))
};
- (@collect, ($($vars:tt)*), ($($args:tt)*), ($($acc:tt)*), ($x:ident? : $ty:ident, $($rest:tt)*)) => {
- match_iter_typed!(@collect, ($($vars)*), ($($args)*), ($($acc)*, $x?), ($($rest)*))
- };
- (@collect, ($($vars:tt)*), ($($args:tt)*), ($($acc:tt)*), ($x:ident* : $ty:ident, $($rest:tt)*)) => {
- match_iter_typed!(@collect, ($($vars)*), ($($args)*), ($($acc)*, $x??), ($($rest)*))
+ (@collect, ($($vars:tt)*), ($($args:tt)*), ($($acc:tt)*), ($x:ident.. : $ty:ident, $($rest:tt)*)) => {
+ match_iter_typed!(@collect, ($($vars)*), ($($args)*), ($($acc)*, $x..), ($($rest)*))
};
// Catch extra comma if exists
(@collect, ($($vars:tt)*), ($($args:tt)*), (,$($acc:tt)*), ($(,)*)) => {
match_iter_typed!(@collect, ($($vars)*), ($($args)*), ($($acc)*), ())
};
(@collect, ($iter:expr, $body:expr, $callback:ident, $error:ident), ($($args:tt)*), ($($acc:tt)*), ($(,)*)) => {
- match_iter!($iter; ($($acc)*) => {
- match_iter_typed!(@callback, $callback, $iter, $($args)*);
- $body
- })
+ {
+ let res = iter_patterns::destructure_iter!($iter; [$($acc)*] => {
+ match_iter_typed!(@callback, $callback, $iter, $($args)*);
+ $body
+ });
+ res.ok_or(IterMatchError::NoMatchFound)
+ }
};
// Pass the matches through the callback
@@ -227,17 +136,7 @@ macro_rules! match_iter_typed {
};
match_iter_typed!(@callback, $callback, $iter $($rest)*);
};
- (@callback, $callback: ident, $iter:expr, $x:ident? : $ty:ident $($rest:tt)*) => {
- let $x = $x.map(|x| $callback!(@type_callback, $ty, x));
- #[allow(unused_mut)]
- let mut $x = match $x {
- Some(Ok(x)) => Some(x),
- Some(Err(e)) => break Err(IterMatchError::Other(e)),
- None => None,
- };
- match_iter_typed!(@callback, $callback, $iter $($rest)*);
- };
- (@callback, $callback: ident, $iter:expr, $x:ident* : $ty:ident $($rest:tt)*) => {
+ (@callback, $callback: ident, $iter:expr, $x:ident.. : $ty:ident $($rest:tt)*) => {
let $x = $x.map(|x| $callback!(@type_callback, $ty, x)).collect();
let $x: Vec<_> = match $x {
Ok(x) => x,
@@ -253,10 +152,13 @@ macro_rules! match_iter_typed {
{
#[allow(unused_mut)]
let mut iter = $iter;
- match_iter_typed!(@collect,
- (iter, $body, $callback, last_error),
- ($($args)*), (), ($($args)*,)
- )
+ let res: Result<_, IterMatchError<_>> = loop {
+ break match_iter_typed!(@collect,
+ (iter, $body, $callback, last_error),
+ ($($args)*), (), ($($args)*,)
+ )
+ };
+ res
}
};
}
@@ -430,7 +332,7 @@ named!(raw_str<&'a str>; captured_str!(s) => s);
named!(label<Label>; captured_str!(s) => Label::from(s.trim().to_owned()));
rule!(double_quote_literal<ParsedText>;
- children!(chunks*: double_quote_chunk) => {
+ children!(chunks..: double_quote_chunk) => {
chunks.collect()
}
);
@@ -639,13 +541,14 @@ rule!(ifthenelse_expression<RcExpr>;
);
rule!(let_expression<RcExpr>;
- children!(bindings*: let_binding, final_expr: expression) => {
+ children!(bindings..: let_binding, final_expr: expression) => {
bindings.fold(final_expr, |acc, x| bx(Expr::Let(x.0, x.1, x.2, acc)))
}
);
rule!(let_binding<(Label, Option<RcExpr>, RcExpr)>;
- children!(name: label, annot?: expression, expr: expression) => (name, annot, expr)
+ children!(name: label, annot: expression, expr: expression) => (name, Some(annot), expr),
+ children!(name: label, expr: expression) => (name, None, expr),
);
rule!(forall_expression<RcExpr>;
@@ -661,9 +564,8 @@ rule!(arrow_expression<RcExpr>;
);
rule!(merge_expression<RcExpr>;
- children!(x: expression, y: expression, z?: expression) => {
- bx(Expr::Merge(x, y, z))
- }
+ children!(x: expression, y: expression, z: expression) => bx(Expr::Merge(x, y, Some(z))),
+ children!(x: expression, y: expression) => bx(Expr::Merge(x, y, None)),
);
rule!(empty_collection<RcExpr>;
@@ -738,7 +640,7 @@ macro_rules! binop {
expression(pair)?
}
}
- // children!(first: expression, rest*: expression) => {
+ // children!(first: expression, rest..: expression) => {
// rest.fold(first, |acc, e| bx(Expr::BinOp(BinOp::$op, acc, e)))
// }
);
@@ -766,7 +668,7 @@ rule!(annotated_expression<RcExpr>;
);
rule!(application_expression<RcExpr>;
- children!(first: expression, rest*: expression) => {
+ children!(first: expression, rest..: expression) => {
let rest: Vec<_> = rest.collect();
if rest.is_empty() {
first
@@ -777,7 +679,7 @@ rule!(application_expression<RcExpr>;
);
rule!(selector_expression_raw<RcExpr>;
- children!(first: expression, rest*: label) => {
+ children!(first: expression, rest..: label) => {
rest.fold(first, |acc, e| bx(Expr::Field(acc, e)))
}
);
@@ -795,7 +697,7 @@ rule!(literal_expression_raw<RcExpr>;
);
rule!(identifier_raw<RcExpr>;
- children!(name: str, idx?: natural_literal_raw) => {
+ children!(name: str, idx: natural_literal_raw) => {
match Builtin::parse(name) {
Some(b) => bx(Expr::Builtin(b)),
None => match name {
@@ -803,10 +705,22 @@ rule!(identifier_raw<RcExpr>;
"False" => bx(Expr::BoolLit(false)),
"Type" => bx(Expr::Const(Const::Type)),
"Kind" => bx(Expr::Const(Const::Kind)),
- name => bx(Expr::Var(V(Label::from(name.to_owned()), idx.unwrap_or(0)))),
+ name => bx(Expr::Var(V(Label::from(name.to_owned()), idx))),
}
}
- }
+ },
+ children!(name: str) => {
+ 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(Label::from(name.to_owned()), 0))),
+ }
+ }
+ },
);
rule!(empty_record_literal<RcExpr>;
@@ -835,7 +749,7 @@ rule!(non_empty_record_type<(RcExpr, BTreeMap<Label, RcExpr>)>;
);
named!(partial_record_entries<(RcExpr, BTreeMap<Label, RcExpr>)>;
- children!(expr: expression, entries*: record_entry) => {
+ children!(expr: expression, entries..: record_entry) => {
(expr, entries.collect())
}
);
@@ -880,7 +794,7 @@ rule!(non_empty_union_type_or_literal
);
rule!(union_type_entries<BTreeMap<Label, RcExpr>>;
- children!(entries*: union_type_entry) => {
+ children!(entries..: union_type_entry) => {
entries.collect()
}
);
@@ -890,7 +804,7 @@ rule!(union_type_entry<(Label, RcExpr)>;
);
rule!(non_empty_list_literal_raw<RcExpr>;
- children!(items*: expression) => {
+ children!(items..: expression) => {
bx(Expr::NEListLit(items.collect()))
}
);
@@ -903,7 +817,7 @@ pub fn parse_expr(s: &str) -> ParseResult<RcExpr> {
let pairs = DhallParser::parse(Rule::final_expression, s)?;
// Match the only item in the pairs iterator
// println!("{}", debug_pair(pairs.clone().next().unwrap()));
- match_iter!(@panic; pairs; (p) => expression(p))
+ iter_patterns::destructure_iter!(pairs; [p] => expression(p)).unwrap()
// Ok(bx(Expr::BoolLit(false)))
}
diff --git a/iter_patterns/Cargo.toml b/iter_patterns/Cargo.toml
new file mode 100644
index 0000000..d63669d
--- /dev/null
+++ b/iter_patterns/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "iter_patterns"
+version = "0.1.0"
+authors = ["Nadrieril <nadrieril@users.noreply.github.com>"]
+edition = "2018"
+
+[lib]
+doctest = false
diff --git a/iter_patterns/src/lib.rs b/iter_patterns/src/lib.rs
new file mode 100644
index 0000000..75fe51c
--- /dev/null
+++ b/iter_patterns/src/lib.rs
@@ -0,0 +1,190 @@
+#![feature(slice_patterns)]
+
+/* Destructure an iterator using the syntax of slice_patterns.
+ * Wraps the match body in `Some` if there was a match; returns
+ * `None` otherwise.
+ * Contrary to slice_patterns, this allows moving out
+ * of the iterator.
+ * A variable length pattern (`x..`) is only allowed as the last
+ * pattern, unless the iterator is double-ended.
+ *
+ * Example:
+ * ```
+ * let vec = vec![Some(1), Some(2), None];
+ *
+ * destructure_iter!(vec.into_iter();
+ * [Some(x), y.., z] => {
+ * // x: usize
+ * // y: impl Iterator<Option<usize>>
+ * // z: Option<usize>
+ * }
+ * )
+ * ```
+ *
+*/
+#[macro_export]
+macro_rules! destructure_iter {
+ // Variable length pattern
+ (@match 0, $iter:expr, ($body:expr), $x:ident.., $($rest:tt)*) => {
+ $crate::destructure_iter!(@match 1, $iter, ({
+ let $x = $iter;
+ $body
+ }), $($rest)*)
+ };
+ // Variable length pattern without a binder
+ (@match 0, $iter:expr, ($body:expr), .., $($rest:tt)*) => {
+ $crate::destructure_iter!(@match 1, $iter, ($body), $($rest)*)
+ };
+ // Single item pattern
+ (@match 0, $iter:expr, ($body:expr), $x:pat, $($rest:tt)*) => {
+ if let Some($x) = $iter.next() {
+ $crate::destructure_iter!(@match 0, $iter, ($body), $($rest)*)
+ } else {
+ None
+ }
+ };
+ // Single item pattern after a variable length one: declare reversed and take from the end
+ (@match 1, $iter:expr, ($body:expr), $x:pat, $($rest:tt)*) => {
+ $crate::destructure_iter!(@match 1, $iter, (
+ if let Some($x) = $iter.next_back() {
+ $body
+ } else {
+ None
+ }
+ ), $($rest)*)
+ };
+
+ // Check no elements remain
+ (@match 0, $iter:expr, ($body:expr) $(,)*) => {
+ if $iter.next().is_some() {
+ None
+ } else {
+ $body
+ }
+ };
+ // After a variable length pattern, everything has already been consumed
+ (@match 1, $iter:expr, ($body:expr) $(,)*) => {
+ $body
+ };
+
+ ($iter:expr; [$($args:tt)*] => $body:expr) => {
+ {
+ #[allow(unused_mut)]
+ let mut iter = $iter;
+ $crate::destructure_iter!(@match 0, iter, (Some($body)), $($args)*,)
+ }
+ };
+}
+
+
+/* Pattern-match on a vec using the syntax of slice_patterns.
+ * Wraps the match body in `Some` if there was a match; returns
+ * `None` otherwise.
+ * A variable length pattern (`x..`) returns an iterator.
+ *
+ * Example:
+ * ```
+ * let vec = vec![Some(1), Some(2), None];
+ *
+ * match_vec!(vec;
+ * [Some(x), y.., z] => {
+ * // x: usize
+ * // y: impl Iterator<Option<usize>>
+ * // z: Option<usize>
+ * }
+ * [x, Some(0)] => {
+ * // x: Option<usize>
+ * },
+ * [..] => { }
+ * )
+ * ```
+ *
+*/
+#[macro_export]
+macro_rules! match_vec {
+ ($arg:expr; $( [$($args:tt)*] => $body:expr ),* $(,)*) => {
+ {
+ let vec = $arg;
+ // Match as references to decide which branch to take
+ // I think `match_default_bindings` should make this always work but
+ // there may be some patterns this doesn't capture.
+ #[allow(unused_variables, unreachable_patterns)]
+ match vec.as_slice() {
+ $(
+ [$($args)*] => {
+ // Actually consume the values
+ #[allow(unused_mut)]
+ let mut iter = vec.into_iter();
+ $crate::destructure_iter!(iter; [$($args)*] => $body)
+ }
+ )*
+ _ => None,
+ }
+ }
+ };
+}
+
+
+/* Pattern-match on an iterator using the syntax of slice_patterns.
+ * Wraps the match body in `Some` if there was a match; returns
+ * `None` otherwise.
+ *
+ * Example:
+ * ```
+ * let vec = vec![Some(1), Some(2), None];
+ *
+ * match_iter!(vec.into_iter();
+ * [Some(x), y.., z] => {
+ * // x: usize
+ * // y: impl Iterator<Option<usize>>
+ * // z: Option<usize>
+ * }
+ * [x, Some(0)] => {
+ * // x: Option<usize>
+ * },
+ * [..] => {
+ * )
+ * ```
+ *
+*/
+#[macro_export]
+macro_rules! match_iter {
+ ($arg:expr; $($args:tt)*) => {
+ {
+ let vec: Vec<_> = $arg.collect();
+ $crate::match_vec!(vec, $($args)*)
+ }
+ };
+}
+
+
+#[test]
+fn test() {
+ let test = |v: Vec<Option<isize>>| {
+ match_vec!(v.into_iter();
+ [Some(_x), None, None] => 4,
+ [Some(_x), None] => 2,
+ [None, Some(y)] => 1,
+ [None, _y..] => 3,
+ [_x.., Some(y), Some(z)] => y - z,
+ [] => 0,
+ [..] => -1,
+ )
+ .unwrap()
+ };
+
+ assert_eq!(test(vec![Some(0), None, None]), 4);
+ assert_eq!(test(vec![Some(0), None]), 2);
+ assert_eq!(test(vec![None, Some(0)]), 1);
+ assert_eq!(test(vec![Some(1), Some(2), Some(5), Some(14)]), -9);
+ assert_eq!(test(vec![None]), 3);
+ assert_eq!(test(vec![]), 0);
+ assert_eq!(test(vec![Some(0)]), -1);
+
+ // Test move out of pattern
+ struct Foo;
+ let _: (Foo, Foo) = match_vec!(vec![Some(Foo), Some(Foo)].into_iter();
+ [Some(f1), Some(f2)] => (f1, f2),
+ )
+ .unwrap();
+}