Merge pull request #238 from epage/macro

WIP: feat(seq): 'seq' macro for easier skipping

examples/css/parser.rs

@@ -1,3 +1,4 @@
+use winnow::combinator::seq;
 use winnow::prelude::*;
 use winnow::token::take_while;
 
@@ -18,10 +19,13 @@ impl std::str::FromStr for Color {
 }
 
 pub fn hex_color(input: &mut &str) -> PResult<Color> {
-    let _ = "#".parse_next(input)?;
-    let (red, green, blue) = (hex_primary, hex_primary, hex_primary).parse_next(input)?;
-
-    Ok(Color { red, green, blue })
+    seq!(Color {
+        _: '#',
+        red: hex_primary,
+        green: hex_primary,
+        blue: hex_primary
+    })
+    .parse_next(input)
 }
 
 fn hex_primary(input: &mut &str) -> PResult<u8> {

examples/http/parser.rs

@@ -1,3 +1,4 @@
+use winnow::combinator::seq;
 use winnow::prelude::*;
 use winnow::{ascii::line_ending, combinator::repeat, token::take_while};
 
@@ -51,18 +52,15 @@ fn request<'s>(input: &mut Stream<'s>) -> PResult<(Request<'s>, Vec<Header<'s>>)
 }
 
 fn request_line<'s>(input: &mut Stream<'s>) -> PResult<Request<'s>> {
-    let method = take_while(1.., is_token).parse_next(input)?;
-    let _ = take_while(1.., is_space).parse_next(input)?;
-    let uri = take_while(1.., is_not_space).parse_next(input)?;
-    let _ = take_while(1.., is_space).parse_next(input)?;
-    let version = http_version(input)?;
-    let _ = line_ending.parse_next(input)?;
-
-    Ok(Request {
-        method,
-        uri,
-        version,
+    seq!( Request {
+        method: take_while(1.., is_token),
+        _: take_while(1.., is_space),
+        uri: take_while(1.., is_not_space),
+        _: take_while(1.., is_space),
+        version: http_version,
+        _: line_ending,
     })
+    .parse_next(input)
 }
 
 fn http_version<'s>(input: &mut Stream<'s>) -> PResult<&'s [u8]> {
@@ -81,11 +79,12 @@ fn message_header_value<'s>(input: &mut Stream<'s>) -> PResult<&'s [u8]> {
 }
 
 fn message_header<'s>(input: &mut Stream<'s>) -> PResult<Header<'s>> {
-    let name = take_while(1.., is_token).parse_next(input)?;
-    let _ = ':'.parse_next(input)?;
-    let value = repeat(1.., message_header_value).parse_next(input)?;
-
-    Ok(Header { name, value })
+    seq!(Header {
+        name: take_while(1.., is_token),
+        _: ':',
+        value: repeat(1.., message_header_value),
+    })
+    .parse_next(input)
 }
 
 #[rustfmt::skip]

examples/http/parser_streaming.rs

@@ -1,3 +1,4 @@
+use winnow::combinator::seq;
 use winnow::{
     ascii::line_ending, combinator::repeat, prelude::*, stream::Partial, token::take_while,
 };
@@ -52,18 +53,15 @@ fn request<'s>(input: &mut Stream<'s>) -> PResult<(Request<'s>, Vec<Header<'s>>)
 }
 
 fn request_line<'s>(input: &mut Stream<'s>) -> PResult<Request<'s>> {
-    let method = take_while(1.., is_token).parse_next(input)?;
-    let _ = take_while(1.., is_space).parse_next(input)?;
-    let uri = take_while(1.., is_not_space).parse_next(input)?;
-    let _ = take_while(1.., is_space).parse_next(input)?;
-    let version = http_version(input)?;
-    let _ = line_ending.parse_next(input)?;
-
-    Ok(Request {
-        method,
-        uri,
-        version,
+    seq!( Request {
+        method: take_while(1.., is_token),
+        _: take_while(1.., is_space),
+        uri: take_while(1.., is_not_space),
+        _: take_while(1.., is_space),
+        version: http_version,
+        _: line_ending,
     })
+    .parse_next(input)
 }
 
 fn http_version<'s>(input: &mut Stream<'s>) -> PResult<&'s [u8]> {
@@ -82,11 +80,12 @@ fn message_header_value<'s>(input: &mut Stream<'s>) -> PResult<&'s [u8]> {
 }
 
 fn message_header<'s>(input: &mut Stream<'s>) -> PResult<Header<'s>> {
-    let name = take_while(1.., is_token).parse_next(input)?;
-    let _ = ':'.parse_next(input)?;
-    let value = repeat(1.., message_header_value).parse_next(input)?;
-
-    Ok(Header { name, value })
+    seq!(Header {
+        name: take_while(1.., is_token),
+        _: ':',
+        value: repeat(1.., message_header_value),
+    })
+    .parse_next(input)
 }
 
 #[rustfmt::skip]

src/combinator/mod.rs

@@ -29,6 +29,7 @@
 //! | combinator | usage | input | new input | output | comment |
 //! |---|---|---|---|---|---|
 //! | [`(...)` (tuples)][crate::Parser] | `("ab", "XY", take(1))` | `"abXYZ!"` | `"!"` | `Ok(("ab", "XY", "Z"))` |Chains parsers and assemble the sub results in a tuple. You can use as many child parsers as you can put elements in a tuple|
+//! | [`seq!`] | `seq!(_: char('('), take(2), _: char(')'))` | `"(ab)cd"` | `"cd"` | `Ok("ab")` ||
 //! | [`delimited`] | `delimited(char('('), take(2), char(')'))` | `"(ab)cd"` | `"cd"` | `Ok("ab")` ||
 //! | [`preceded`] | `preceded("ab", "XY")` | `"abXYZ"` | `"Z"` | `Ok("XY")` ||
 //! | [`terminated`] | `terminated("ab", "XY")` | `"abXYZ"` | `"Z"` | `Ok("ab")` ||

src/combinator/sequence.rs

@@ -3,12 +3,17 @@ use crate::stream::Stream;
 use crate::trace::trace;
 use crate::*;
 
+#[doc(inline)]
+pub use crate::seq;
+
 /// Sequence two parsers, only returning the output from the second.
 ///
 /// # Arguments
 /// * `first` The opening parser.
 /// * `second` The second parser to get object.
 ///
+/// See also [`seq`] to generalize this across any number of fields.
+///
 /// # Example
 ///
 /// ```rust
@@ -47,6 +52,8 @@ where
 /// * `first` The first parser to apply.
 /// * `second` The second parser to match an object.
 ///
+/// See also [`seq`] to generalize this across any number of fields.
+///
 /// # Example
 ///
 /// ```rust
@@ -86,6 +93,8 @@ where
 /// * `sep` The separator parser to apply.
 /// * `second` The second parser to apply.
 ///
+/// See also [`seq`] to generalize this across any number of fields.
+///
 /// # Example
 ///
 /// ```rust
@@ -127,6 +136,8 @@ where
 /// * `second` The second parser to apply.
 /// * `third` The third parser to apply and discard.
 ///
+/// See also [`seq`] to generalize this across any number of fields.
+///
 /// # Example
 ///
 /// ```rust

src/macros/mod.rs

@@ -1,4 +1,5 @@
 mod dispatch;
+mod seq;
 
 #[cfg(test)]
 mod test;