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refactor: replace imperative parsing loop with functional combinators #230

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Merged
merged 1 commit into from
Sep 15, 2025
Merged

refactor: replace imperative parsing loop with functional combinators #230

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25 changes: 24 additions & 1 deletion src/items/builder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@

use jiff::{civil, Span, Zoned};

use super::{date, epoch, error, relative, time, timezone, weekday, year};
use super::{date, epoch, error, relative, time, timezone, weekday, year, Item};

/// The builder is used to construct a DateTime object from various components.
/// The parser creates a `DateTimeBuilder` object with the parsed components,
Expand Down Expand Up @@ -248,3 +248,26 @@ impl DateTimeBuilder {
Ok(dt)
}
}

impl TryFrom<Vec<Item>> for DateTimeBuilder {
type Error = &'static str;

fn try_from(items: Vec<Item>) -> Result<Self, Self::Error> {
let mut builder = DateTimeBuilder::new();

for item in items {
builder = match item {
Item::Timestamp(ts) => builder.set_timestamp(ts)?,
Item::DateTime(dt) => builder.set_date(dt.date)?.set_time(dt.time)?,
Item::Date(d) => builder.set_date(d)?,
Item::Time(t) => builder.set_time(t)?,
Item::Weekday(weekday) => builder.set_weekday(weekday)?,
Item::TimeZone(tz) => builder.set_timezone(tz)?,
Item::Relative(rel) => builder.push_relative(rel)?,
Item::Pure(pure) => builder.set_pure(pure)?,
}
}

Ok(builder)
}
}
85 changes: 24 additions & 61 deletions src/items/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,7 @@ pub(crate) mod error;
use jiff::Zoned;
use primitive::space;
use winnow::{
combinator::{alt, eof, terminated, trace},
combinator::{alt, eof, preceded, repeat_till, terminated, trace},
error::{AddContext, ContextError, ErrMode, StrContext, StrContextValue},
stream::Stream,
ModalResult, Parser,
Expand All @@ -70,7 +70,8 @@ enum Item {
Pure(String),
}

/// Parse a date and time string based on a specific date.
/// Parse a date and time string and build a `Zoned` object. The parsed result
/// is resolved against the given base date and time.
pub(crate) fn parse_at_date<S: AsRef<str> + Clone>(base: Zoned, input: S) -> Result<Zoned, Error> {
let input = input.as_ref().to_ascii_lowercase();
match parse(&mut input.as_str()) {
Expand All @@ -79,11 +80,12 @@ pub(crate) fn parse_at_date<S: AsRef<str> + Clone>(base: Zoned, input: S) -> Res
}
}

/// Parse a date and time string based on the current local time.
/// Parse a date and time string and build a `Zoned` object. The parsed result
/// is resolved against the current local date and time.
pub(crate) fn parse_at_local<S: AsRef<str> + Clone>(input: S) -> Result<Zoned, Error> {
let input = input.as_ref().to_ascii_lowercase();
match parse(&mut input.as_str()) {
Ok(builder) => builder.build(),
Ok(builder) => builder.build(), // the builder uses current local date and time if no base is given.
Err(e) => Err(e.into()),
}
}
Expand Down Expand Up @@ -196,7 +198,7 @@ fn parse(input: &mut &str) -> ModalResult<DateTimeBuilder> {
fn parse_timestamp(input: &mut &str) -> ModalResult<DateTimeBuilder> {
trace(
"parse_timestamp",
terminated(epoch::parse.map(Item::Timestamp), eof),
terminated(epoch::parse.map(Item::Timestamp), preceded(space, eof)),
)
.verify_map(|ts: Item| {
if let Item::Timestamp(ts) = ts {
Expand All @@ -210,59 +212,13 @@ fn parse_timestamp(input: &mut &str) -> ModalResult<DateTimeBuilder> {

/// Parse a sequence of items.
fn parse_items(input: &mut &str) -> ModalResult<DateTimeBuilder> {
let mut builder = DateTimeBuilder::new();

loop {
match parse_item.parse_next(input) {
Ok(item) => match item {
Item::Timestamp(ts) => {
builder = builder
.set_timestamp(ts)
.map_err(|e| expect_error(input, e))?;
}
Item::DateTime(dt) => {
builder = builder
.set_date(dt.date)
.map_err(|e| expect_error(input, e))?
.set_time(dt.time)
.map_err(|e| expect_error(input, e))?;
}
Item::Date(d) => {
builder = builder.set_date(d).map_err(|e| expect_error(input, e))?;
}
Item::Time(t) => {
builder = builder.set_time(t).map_err(|e| expect_error(input, e))?;
}
Item::Weekday(weekday) => {
builder = builder
.set_weekday(weekday)
.map_err(|e| expect_error(input, e))?;
}
Item::TimeZone(tz) => {
builder = builder
.set_timezone(tz)
.map_err(|e| expect_error(input, e))?;
}
Item::Relative(rel) => {
builder = builder
.push_relative(rel)
.map_err(|e| expect_error(input, e))?;
}
Item::Pure(pure) => {
builder = builder.set_pure(pure).map_err(|e| expect_error(input, e))?;
}
},
Err(ErrMode::Backtrack(_)) => break,
Err(e) => return Err(e),
}
}

space.parse_next(input)?;
if !input.is_empty() {
return Err(expect_error(input, "unexpected input"));
}
let (items, _): (Vec<Item>, _) = trace(
"parse_items",
repeat_till(0.., parse_item, preceded(space, eof)),
)
.parse_next(input)?;

Ok(builder)
items.try_into().map_err(|e| expect_error(input, e))
}

/// Parse an item.
Expand Down Expand Up @@ -346,6 +302,11 @@ mod tests {
test_eq_fmt("%Y-%m-%dT%H:%M:%S%:z", "@1690466034")
);

assert_eq!(
"2023-07-27T13:53:54+00:00",
test_eq_fmt("%Y-%m-%dT%H:%M:%S%:z", " @1690466034 ")
);

// https://github.com/uutils/coreutils/issues/6398
// TODO: make this work
// assert_eq!("1111 1111 00", test_eq_fmt("%m%d %H%M %S", "11111111"));
Expand All @@ -371,6 +332,12 @@ mod tests {
);
}

#[test]
fn empty() {
let result = parse(&mut "");
assert!(result.is_ok());
}

#[test]
fn invalid() {
let result = parse(&mut "2025-05-19 2024-05-20 06:14:49");
Expand All @@ -396,7 +363,6 @@ mod tests {

let result = parse(&mut "2025-05-19 +00:00 +01:00");
assert!(result.is_err());
assert!(result.unwrap_err().to_string().contains("unexpected input"));

let result = parse(&mut "m1y");
assert!(result.is_err());
Expand All @@ -407,15 +373,12 @@ mod tests {

let result = parse(&mut "2025-05-19 abcdef");
assert!(result.is_err());
assert!(result.unwrap_err().to_string().contains("unexpected input"));

let result = parse(&mut "@1690466034 2025-05-19");
assert!(result.is_err());
assert!(result.unwrap_err().to_string().contains("unexpected input"));

let result = parse(&mut "2025-05-19 @1690466034");
assert!(result.is_err());
assert!(result.unwrap_err().to_string().contains("unexpected input"));

// Pure number as year (too large).
let result = parse(&mut "jul 18 12:30 10000");
Expand Down
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