diff options
| -rw-r--r-- | dhall/src/parser.rs | 138 | ||||
| -rw-r--r-- | dhall/tests/macros.rs | 1 |
2 files changed, 108 insertions, 31 deletions
diff --git a/dhall/src/parser.rs b/dhall/src/parser.rs index 6fb6e1d..c4f4ce2 100644 --- a/dhall/src/parser.rs +++ b/dhall/src/parser.rs @@ -1,5 +1,5 @@ use std::collections::BTreeMap; -use itertools::*; +// use itertools::*; use lalrpop_util; use pest::Parser; use pest::iterators::Pair; @@ -24,6 +24,36 @@ pub fn custom_parse_error(pair: &Pair<Rule>, msg: String) -> ParseError { pest::error::Error::new_from_span(e, pair.as_span()) } +fn debug_pair(pair: Pair<Rule>) -> String { + use std::fmt::Write; + let mut s = String::new(); + fn aux(s: &mut String, indent: usize, prefix: String, pair: Pair<Rule>) { + let indent_str = "| ".repeat(indent); + let rule = pair.as_rule(); + let contents = pair.as_str().clone(); + let mut inner = pair.into_inner(); + let mut first = true; + while let Some(p) = inner.next() { + if first { + first = false; + let last = inner.peek().is_none(); + if last && p.as_str() == contents { + let prefix = format!("{}{:?} > ", prefix, rule); + aux(s, indent, prefix, p); + continue; + } else { + writeln!(s, r#"{}{}{:?}: "{}""#, indent_str, prefix, rule, contents).unwrap(); + } + } + aux(s, indent+1, "".into(), p); + } + if first { + writeln!(s, r#"{}{}{:?}: "{}""#, indent_str, prefix, rule, contents).unwrap(); + } + } + aux(&mut s, 0, "".into(), pair); + s +} /* Macro to pattern-match iterators. * Panics if the sequence doesn't match; @@ -45,7 +75,13 @@ pub fn custom_parse_error(pair: &Pair<Rule>, msg: String) -> ParseError { * }) * ``` * - */ +*/ +#[derive(Debug)] +enum IterMatchError<T> { + NotEnoughItems, + TooManyItems, + Other(T), // Allow other macros to inkect their own errors +} macro_rules! match_iter { // Everything else pattern (@match 0, $iter:expr, $x:ident* $($rest:tt)*) => { @@ -63,11 +99,17 @@ macro_rules! match_iter { (@match 0, $iter:expr, $x:ident? $($rest:tt)*) => { match_iter!(@match 1, $iter $($rest)*); let $x = $iter.next(); - $iter.next().ok_or(()).expect_err("Some values remain unused"); + match $iter.next() { + Some(_) => break Err(IterMatchError::TooManyItems), + None => {}, + }; }; // Normal pattern (@match 0, $iter:expr, $x:ident $($rest:tt)*) => { - let $x = $iter.next().unwrap(); + let $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 @@ -78,17 +120,29 @@ macro_rules! match_iter { // Check no elements remain (@match 0, $iter:expr) => { - $iter.next().ok_or(()).expect_err("Some values remain unused"); + match $iter.next() { + Some(_) => break Err(IterMatchError::TooManyItems), + None => {}, + }; }; (@match $_:expr, $iter:expr) => {}; - // Entrypoint - ($iter:expr; ($($args:tt)*) => $body:expr) => { + // Entrypoints + (@get_err, $iter:expr; ($($args:tt)*) => $body:expr) => { { #[allow(unused_mut)] let mut iter = $iter; - match_iter!(@match 0, iter, $($args)*); - $body + let ret: Result<_, IterMatchError<_>> = loop { + match_iter!(@match 0, iter, $($args)*); + break Ok($body); + }; + ret + } + }; + ($($args:tt)*) => { + { + let ret: Result<_, IterMatchError<()>> = match_iter!(@get_err, $($args)*); + ret.unwrap() } }; } @@ -115,38 +169,61 @@ macro_rules! match_children { match_children!(@collect, $pairs, ($($args)*), $body, ($($acc)*, $x??), ($($rest)*)) }; (@collect, $pairs:expr, ($($args:tt)*), $body:expr, (,$($acc:tt)*), ()) => { - match_iter!($pairs; ($($acc)*) => { - match_children!(@parse, $pairs, $($args)*); - Ok($body) - }) + let matched: Result<_, IterMatchError<ParseError>> = + match_iter!(@get_err, $pairs; ($($acc)*) => { + match_children!(@parse, $pairs, $($args)*); + Ok($body) + }); + match matched { + Ok(v) => break v, + Err(_) => {}, + }; }; (@parse, $pairs:expr, $x:ident : $ty:ident $($rest:tt)*) => { - let $x = $ty($x)?; + let $x = $ty($x); + let $x = match $x { + Ok(x) => x, + Err(e) => break Err(IterMatchError::Other(e)), + }; match_children!(@parse, $pairs $($rest)*); }; (@parse, $pairs:expr, $x:ident? : $ty:ident $($rest:tt)*) => { - let $x = $x.map($ty).transpose()?; + let $x = $x.map($ty).transpose(); + let $x = match $x { + Ok(x) => x, + Err(e) => break Err(IterMatchError::Other(e)), + }; match_children!(@parse, $pairs $($rest)*); }; (@parse, $pairs:expr, $x:ident* : $ty:ident $($rest:tt)*) => { + let $x = $x.map($ty).collect::<ParseResult<Vec<_>>>(); #[allow(unused_mut)] - let mut $x = $x.map($ty); + let mut $x = match $x { + Ok(x) => x.into_iter(), + Err(e) => break Err(IterMatchError::Other(e)), + }; match_children!(@parse, $pairs $($rest)*); }; (@parse, $pairs:expr) => {}; - // Entrypoints - ($pair:expr; $($rest:tt)*) => { + // Entrypoint + ($pair:expr; $( ($($args:tt)*) => $body:expr ),* $(,)*) => { { + let pair = $pair; #[allow(unused_mut)] - let mut pairs = $pair.into_inner(); - match_children!(@pairs; pairs; $($rest)*) + let mut pairs = pair.clone().into_inner(); + // Would use loop labels but they create warnings + #[allow(unreachable_code)] + loop { + $( + match_children!(@collect, pairs.clone(), ($($args)*), $body, (), ($($args)*,)); + )* + // break Err(TODO); + panic!("No match found while matching on:\n{}", debug_pair(pair)); + } } }; - (@pairs; $pairs:expr; ($($args:tt)*) => $body:expr) => { - match_children!(@collect, $pairs, ($($args)*), $body, (), ($($args)*,)) - }; } macro_rules! with_captured_str { @@ -189,7 +266,7 @@ macro_rules! binop { { let f = $f; match_children!($pair; (first: expression, rest*: expression) => { - rest.fold_results(first, |acc, e| bx(f(acc, e)))? + rest.fold(first, |acc, e| bx(f(acc, e))) }) } }; @@ -245,11 +322,10 @@ named!(record_entry<(&'a str, BoxExpr<'a>)>; ); named!(partial_record_entries<(Rule, BoxExpr<'a>, BTreeMap<&'a str, ParsedExpr<'a>>)>; - with_rule!(rule; + 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?; + for (n, e) in entries { map.insert(n, *e); } (rule, expr, map) @@ -287,7 +363,7 @@ named!(expression<BoxExpr<'a>>; match_rule!( 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)))? + bindings.fold(final_expr, |acc, x| bx(Expr::Let(x.0, x.1, x.2, acc))) }), Rule::forall_expression => @@ -317,7 +393,7 @@ named!(expression<BoxExpr<'a>>; match_rule!( Rule::selector_expression_raw => match_children!((first: expression, rest*: str) => { - rest.fold_results(first, |acc, e| bx(Expr::Field(acc, e)))? + rest.fold(first, |acc, e| bx(Expr::Field(acc, e))) }), Rule::empty_record_type => plain_value!(bx(Expr::Record(BTreeMap::new()))), @@ -335,9 +411,9 @@ named!(expression<BoxExpr<'a>>; match_rule!( _ => with_rule!(rule; match_children!((exprs*: expression) => { - // panic!(); let rulename = format!("{:?}", rule); - bx(Expr::FailedParse(rulename, exprs.map_results(|x| *x).collect::<ParseResult<_>>()?)) + // panic!(rulename); + bx(Expr::FailedParse(rulename, exprs.map(|x| *x).collect())) }) ), )); diff --git a/dhall/tests/macros.rs b/dhall/tests/macros.rs index a9bc770..956fa1f 100644 --- a/dhall/tests/macros.rs +++ b/dhall/tests/macros.rs @@ -18,6 +18,7 @@ macro_rules! parse_str { Ok(larlpop_expr) => assert_eq!(pest_expr, larlpop_expr), Err(_) => {}, }; + // panic!("{:?}", pest_expr); pest_expr } }; |