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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /third_party/rust/nom/tests/arithmetic.rs | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/nom/tests/arithmetic.rs')
-rw-r--r-- | third_party/rust/nom/tests/arithmetic.rs | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/third_party/rust/nom/tests/arithmetic.rs b/third_party/rust/nom/tests/arithmetic.rs new file mode 100644 index 0000000000..5b627a97a5 --- /dev/null +++ b/third_party/rust/nom/tests/arithmetic.rs @@ -0,0 +1,94 @@ +use nom::{ + branch::alt, + bytes::complete::tag, + character::complete::char, + character::complete::{digit1 as digit, space0 as space}, + combinator::map_res, + multi::fold_many0, + sequence::{delimited, pair}, + IResult, +}; + +// Parser definition + +use std::str::FromStr; + +// We parse any expr surrounded by parens, ignoring all whitespaces around those +fn parens(i: &str) -> IResult<&str, i64> { + delimited(space, delimited(tag("("), expr, tag(")")), space)(i) +} + +// We transform an integer string into a i64, ignoring surrounding whitespaces +// We look for a digit suite, and try to convert it. +// If either str::from_utf8 or FromStr::from_str fail, +// we fallback to the parens parser defined above +fn factor(i: &str) -> IResult<&str, i64> { + alt(( + map_res(delimited(space, digit, space), FromStr::from_str), + parens, + ))(i) +} + +// We read an initial factor and for each time we find +// a * or / operator followed by another factor, we do +// the math by folding everything +fn term(i: &str) -> IResult<&str, i64> { + let (i, init) = factor(i)?; + + fold_many0( + pair(alt((char('*'), char('/'))), factor), + move || init, + |acc, (op, val): (char, i64)| { + if op == '*' { + acc * val + } else { + acc / val + } + }, + )(i) +} + +fn expr(i: &str) -> IResult<&str, i64> { + let (i, init) = term(i)?; + + fold_many0( + pair(alt((char('+'), char('-'))), term), + move || init, + |acc, (op, val): (char, i64)| { + if op == '+' { + acc + val + } else { + acc - val + } + }, + )(i) +} + +#[test] +fn factor_test() { + assert_eq!(factor("3"), Ok(("", 3))); + assert_eq!(factor(" 12"), Ok(("", 12))); + assert_eq!(factor("537 "), Ok(("", 537))); + assert_eq!(factor(" 24 "), Ok(("", 24))); +} + +#[test] +fn term_test() { + assert_eq!(term(" 12 *2 / 3"), Ok(("", 8))); + assert_eq!(term(" 2* 3 *2 *2 / 3"), Ok(("", 8))); + assert_eq!(term(" 48 / 3/2"), Ok(("", 8))); +} + +#[test] +fn expr_test() { + assert_eq!(expr(" 1 + 2 "), Ok(("", 3))); + assert_eq!(expr(" 12 + 6 - 4+ 3"), Ok(("", 17))); + assert_eq!(expr(" 1 + 2*3 + 4"), Ok(("", 11))); +} + +#[test] +fn parens_test() { + assert_eq!(expr(" ( 2 )"), Ok(("", 2))); + assert_eq!(expr(" 2* ( 3 + 4 ) "), Ok(("", 14))); + assert_eq!(expr(" 2*2 / ( 5 - 1) + 3"), Ok(("", 4))); +} |