diff options
author | Greg Brown <gmb60@cam.ac.uk> | 2021-04-20 13:22:49 +0100 |
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committer | Greg Brown <gmb60@cam.ac.uk> | 2021-04-20 13:22:49 +0100 |
commit | bb3c8d1455f7a102a0c0abffd757ccace94f77d5 (patch) | |
tree | 5c2793598c781c648c4d9cd103414ff47d88adc1 /chomp-bench/src/arith/mod.rs | |
parent | 15f5491028b11bd821bd141183e8b5bf8c1c46af (diff) |
Add LALRPOP arithmetic parser.
Diffstat (limited to 'chomp-bench/src/arith/mod.rs')
-rw-r--r-- | chomp-bench/src/arith/mod.rs | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/chomp-bench/src/arith/mod.rs b/chomp-bench/src/arith/mod.rs index 37432d5..38556fe 100644 --- a/chomp-bench/src/arith/mod.rs +++ b/chomp-bench/src/arith/mod.rs @@ -1,39 +1,51 @@ use chewed::{ParseError, TakeError}; +use lalrpop_util::lalrpop_mod; pub mod nibble; +lalrpop_mod!(pub lalr, "/arith/lalr.rs"); pub fn take_number<P: chewed::Parser + ?Sized>(input: &mut P) -> Result<i64, TakeError> { let mut out = None; loop { - match input.next() { + match input.peek() { Some('0') => { + input.consume_str("0")?; out = Some(out.unwrap_or_default() * 10); } Some('1') => { + input.consume_str("1")?; out = Some(out.unwrap_or_default() * 10 + 1); } Some('2') => { + input.consume_str("2")?; out = Some(out.unwrap_or_default() * 10 + 2); } Some('3') => { + input.consume_str("3")?; out = Some(out.unwrap_or_default() * 10 + 3); } Some('4') => { + input.consume_str("4")?; out = Some(out.unwrap_or_default() * 10 + 4); } Some('5') => { + input.consume_str("5")?; out = Some(out.unwrap_or_default() * 10 + 5); } Some('6') => { + input.consume_str("6")?; out = Some(out.unwrap_or_default() * 10 + 6); } Some('7') => { + input.consume_str("7")?; out = Some(out.unwrap_or_default() * 10 + 7); } Some('8') => { + input.consume_str("8")?; out = Some(out.unwrap_or_default() * 10 + 8); } Some('9') => { + input.consume_str("9")?; out = Some(out.unwrap_or_default() * 10 + 9); } Some(c) => { @@ -80,13 +92,15 @@ pub fn take_product<P: chewed::Parser + ?Sized>(input: &mut P) -> Result<i64, Ta let mut out = take_term(input)?; while let Some(c) = input.peek() { if c == '*' { + input.consume_str("*")?; input.skip_while(|c| c == ' '); out *= take_term(input)?; } else if c == '/' { + input.consume_str("/")?; input.skip_while(|c| c == ' '); - out -= take_term(input)?; + out /= take_term(input)?; } else { - return Err(TakeError::BadBranch(input.pos(), c, &['*', '/'])); + break } } Ok(out) @@ -96,13 +110,15 @@ pub fn take_expr<P: chewed::Parser + ?Sized>(input: &mut P) -> Result<i64, TakeE let mut out = take_product(input)?; while let Some(c) = input.peek() { if c == '+' { + input.consume_str("+")?; input.skip_while(|c| c == ' '); out += take_product(input)?; } else if c == '-' { + input.consume_str("-")?; input.skip_while(|c| c == ' '); out -= take_product(input)?; } else { - return Err(TakeError::BadBranch(input.pos(), c, &['+', '-'])); + break } } Ok(out) |