From 5745299a328462f0a60e56a9d11cbc60a0e4380d Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Wed, 20 Mar 2019 20:24:58 +0100 Subject: Cleanup parser code --- dhall_core/src/lib.rs | 1 - dhall_core/src/parser.rs | 173 ++++++++++++++--------------------------------- 2 files changed, 49 insertions(+), 125 deletions(-) (limited to 'dhall_core') diff --git a/dhall_core/src/lib.rs b/dhall_core/src/lib.rs index 508ad3a..6215456 100644 --- a/dhall_core/src/lib.rs +++ b/dhall_core/src/lib.rs @@ -1,6 +1,5 @@ #![feature(trace_macros)] #![feature(slice_patterns)] -#![recursion_limit = "128"] #![allow( clippy::many_single_char_names, clippy::should_implement_trait, diff --git a/dhall_core/src/parser.rs b/dhall_core/src/parser.rs index 30e3367..cbba8ca 100644 --- a/dhall_core/src/parser.rs +++ b/dhall_core/src/parser.rs @@ -107,7 +107,7 @@ macro_rules! match_pair { { let pair = $pair.clone(); let rule = pair.as_rule(); - let parsed: Vec<_> = pair.clone().into_inner().map(ParseWrapped::parse_any_fast).collect::>()?; + let parsed: Vec<_> = pair.clone().into_inner().map(parse_any).collect::>()?; #[allow(unreachable_code)] iter_patterns::match_vec!(parsed; $($acc)* @@ -119,48 +119,32 @@ macro_rules! match_pair { ($pair:expr; $( $submac:ident!($($args:tt)*) => $body:expr ),* $(,)*) => { match_pair!(@make_matches, $pair, (), $( $submac!($($args)*) => $body ),* ,) }; - ($pair:expr; $($args:tt)*) => { - { - let pair = $pair; - let result = match_iter_branching!(@noclone, match_pair; pair; $($args)*); - result.map_err(|e| match e { - IterMatchError::Other(e) => e, - _ => custom_parse_error(&pair, "No match found".to_owned()), - }) - } - }; } macro_rules! make_parser { - (@branch_rules, $pair:expr, ($($acc:tt)*), rule!( $name:ident<$o:ty>; $($args:tt)* ); $($rest:tt)*) => ( - make_parser!(@branch_rules, $pair, ($($acc)* Rule::$name => { - ParseWrapped::$name($pair) - },), $($rest)*) - ); - (@branch_rules, $pair:expr, ($($acc:tt)*), rule_in_group!( $name:ident<$o:ty>; $group:ident; $($args:tt)* ); $($rest:tt)*) => ( - make_parser!(@branch_rules, $pair, ($($acc)* Rule::$name => { - ParseWrapped::$name($pair).map(|x| x.$name()).map(ParsedValue::$group) - },), $($rest)*) - ); - (@branch_rules, $pair:expr, ($($acc:tt)*), binop!( $name:ident<$o:ty>; $op:ident ); $($rest:tt)*) => ( - make_parser!(@branch_rules, $pair, ($($acc)* Rule::$name => { - parse_binop($pair, BinOp::$op).map(ParsedValue::expression) - },), $($rest)*) + // Filter out definitions that should not be matched on + (@filter, rule) => (true); + (@filter, rule_in_group) => (true); + (@filter, binop) => (true); + (@filter, rule_group) => (false); + + (@body, $pair:expr, rule!( $name:ident<$o:ty>; $($args:tt)* )) => ( { + let res: $o = match_pair!($pair; $($args)*)?; + Ok(ParsedValue::$name(res)) + }); + (@body, $pair:expr, rule_in_group!( $name:ident<$o:ty>; $group:ident; $($args:tt)* )) => ( { + let res: $o = match_pair!($pair; $($args)*)?; + Ok(ParsedValue::$group(res)) + }); + (@body, $pair:expr, binop!( $name:ident<$o:ty>; $op:ident )) => ( { + parse_binop($pair, BinOp::$op) + }); + (@body, $pair:expr, rule_group!( $name:ident<$o:ty> )) => ( + unreachable!() ); - // (@branch_rules, $pair:expr, ($($acc:tt)*), rule_group!( $name:ident<$o:ty>; $($ty:ident),* ); $($rest:tt)*) => ( - // make_parser!(@branch_rules, $pair, ($($acc)* $( Rule::$ty => ParseUnwrapped::$ty($pair).map(ParsedValue::$name),)* ), $($rest)*) - // ); - (@branch_rules, $pair:expr, ($($acc:tt)*), $submac:ident!( $name:ident<$o:ty>; $($args:tt)* ); $($rest:tt)*) => ( - make_parser!(@branch_rules, $pair, ($($acc)*), $($rest)*) - ); - (@branch_rules, $pair:expr, ($($acc:tt)*),) => ( - #[allow(unreachable_patterns)] - match $pair.as_rule() { - $($acc)* - r => Err(custom_parse_error(&$pair, format!("parse_any_fast: Unexpected {:?}", r))), - } - ); - ($( $submac:ident!( $name:ident<$o:ty>; $($args:tt)* ); )*) => ( + + + ($( $submac:ident!( $name:ident<$o:ty> $($args:tt)* ); )*) => ( // #[allow(non_camel_case_types, dead_code)] // enum ParsedType { // $( $name, )* @@ -182,8 +166,6 @@ macro_rules! make_parser { // // } // // } // } - struct ParseWrapped; - struct ParseUnwrapped; #[allow(non_camel_case_types, dead_code)] #[derive(Debug)] @@ -203,71 +185,22 @@ macro_rules! make_parser { )* } - impl ParseWrapped { - #[allow(non_snake_case, dead_code)] - fn parse_any_fast(pair: Pair) -> ParseResult { - make_parser!(@branch_rules, pair, (), $( $submac!( $name<$o>; $($args)* ); )*) + #[allow(non_snake_case, dead_code)] + fn parse_any<'a>(pair: Pair<'a, Rule>) -> ParseResult> { + #[allow(unreachable_patterns)] + match pair.as_rule() { + $( + Rule::$name if make_parser!(@filter, $submac) + => + make_parser!(@body, pair, $submac!( $name<$o> $($args)* )) + , + )* + r => Err(custom_parse_error(&pair, format!("parse_any: Unexpected {:?}", r))), } } - - impl ParseUnwrapped { - #[allow(unused_variables, non_snake_case, dead_code, clippy::all)] - fn expression<'a>(pair: Pair<'a, Rule>) -> ParseResult { - ParseWrapped::expression(pair).map(|x| x.expression()) - } - } - impl ParseWrapped { - #[allow(unused_variables, non_snake_case, dead_code, clippy::all)] - fn expression<'a>(pair: Pair<'a, Rule>) -> ParseResult> { - ParseWrapped::parse_any_fast(pair) - } - } - - // fn do_the_parse(s: &str, r: Rule, ty: ParsedType) -> ParseResult { - // let pairs = DhallParser::parse(r, s)?; - // match_iter!(pairs; (e) => ty.parse(e)) - // } - - $( - $submac!($name<$o>; $($args)*); - )* ); } -macro_rules! make_pest_parse_function { - ($name:ident<$o:ty>; $submac:ident!( $($args:tt)* )) => ( - impl ParseUnwrapped { - #[allow(unused_variables, non_snake_case, dead_code, clippy::all)] - fn $name<'a>(pair: Pair<'a, Rule>) -> ParseResult<$o> { - ParseWrapped::$name(pair).map(|x| x.$name()) - } - } - impl ParseWrapped { - #[allow(unused_variables, non_snake_case, dead_code, clippy::all)] - fn $name<'a>(pair: Pair<'a, Rule>) -> ParseResult> { - let res: ParseResult<$o> = $submac!(pair; $($args)*); - Ok(ParsedValue::$name(res?)) - } - } - ); -} - -macro_rules! rule { - ($name:ident<$o:ty>; $($args:tt)*) => ( - make_pest_parse_function!($name<$o>; match_pair!( $($args)* )); - ); -} - -macro_rules! rule_in_group { - ($name:ident<$o:ty>; $group:ident; $($args:tt)*) => ( - make_pest_parse_function!($name<$o>; match_pair!( $($args)* )); - ); -} - -macro_rules! rule_group { - ($name:ident<$o:ty>; $($ty:ident),*) => (); -} - // List of rules that can be shortcutted as implemented in parse_binop fn can_be_shortcutted(rule: Rule) -> bool { use Rule::*; @@ -291,21 +224,25 @@ fn can_be_shortcutted(rule: Rule) -> bool { } } -fn parse_binop(pair: Pair, o: BinOp) -> ParseResult { +fn parse_binop(pair: Pair, o: BinOp) -> ParseResult { // This all could be a trivial fold, but to avoid stack explosion // we try to cut down on the recursion level here, by consuming // chains of blah_expression > ... > blih_expression in one go. let mut pair = pair; let mut pairs = pair.into_inner(); let first = pairs.next().unwrap(); - let rest: Vec<_> = pairs.map(ParseUnwrapped::expression).collect::>()?; + let rest: Vec<_> = pairs + .map(|p| parse_any(p).map(|x| x.expression())) + .collect::>()?; if !rest.is_empty() { // If there is more than one subexpression, handle it normally - let first = ParseUnwrapped::expression(first)?; - Ok(rest.into_iter().fold(first, |acc, e| bx(Expr::BinOp(o, acc, e)))) + let first = parse_any(first)?.expression(); + Ok(ParsedValue::expression( + rest.into_iter() + .fold(first, |acc, e| bx(Expr::BinOp(o, acc, e))), + )) } else { // Otherwise, consume short-cuttable rules as long as they contain only one subexpression. - // println!("short-cutting {}", debug_pair(pair.clone())); pair = first; while can_be_shortcutted(pair.as_rule()) { let mut pairs = pair.clone().into_inner(); @@ -316,22 +253,10 @@ fn parse_binop(pair: Pair, o: BinOp) -> ParseResult { } pair = first; } - // println!("short-cutted {}", debug_pair(pair.clone())); - // println!(); - Ok(ParseUnwrapped::expression(pair)?) + parse_any(pair) } } -macro_rules! binop { - ($rule:ident<$ty:ty>; $op:ident) => { - rule!($rule<$ty>; - raw_pair!(pair) => { - parse_binop(pair, BinOp::$op)? - } - ); - }; -} - make_parser! { rule!(EOI<()>; children!() => ()); @@ -450,7 +375,7 @@ rule!(path; captured_str!(s) => (".".to_owned() + s).into() ); -rule_group!(local_raw<(FilePrefix, PathBuf)>;); +rule_group!(local_raw<(FilePrefix, PathBuf)>); rule_in_group!(parent_path<(FilePrefix, PathBuf)>; local_raw; children!(p: path) => (FilePrefix::Parent, p) @@ -492,7 +417,7 @@ rule!(import_hashed_raw<(ImportLocation, Option<()>)>; } ); -rule_group!(expression;); +rule_group!(expression); rule_in_group!(import_raw; expression; // TODO: handle "as Text" @@ -746,11 +671,11 @@ pub fn parse_expr(s: &str) -> ParseResult { let pairs = DhallParser::parse(Rule::final_expression, s)?; // Match the only item in the pairs iterator // println!("{}", debug_pair(pairs.clone().next().unwrap())); - let expr = iter_patterns::destructure_iter!(pairs; [p] => ParseUnwrapped::expression(p)) + let expr = iter_patterns::destructure_iter!(pairs; [p] => parse_any(p)) .unwrap()?; // expr.expression() - // Ok(expr.expression()) - Ok(expr) + Ok(expr.expression()) + // Ok(expr) // Ok(bx(Expr::BoolLit(false))) } -- cgit v1.2.3