Rewrite doc_comment_contents without macros

Author: dtolnay

src/fallback.rs

@@ -1,4 +1,4 @@
-use crate::strnom::{block_comment, skip_whitespace, whitespace, word_break, Cursor, PResult};
+use crate::strnom::{block_comment, skip_whitespace, word_break, Cursor, PResult};
 use crate::{Delimiter, Punct, Spacing, TokenTree};
 #[cfg(span_locations)]
 use std::cell::RefCell;
@@ -1435,31 +1435,33 @@ fn doc_comment(input: Cursor) -> PResult<Vec<TokenTree>> {
     Ok((rest, trees))
 }
 
-named!(doc_comment_contents -> (&str, bool), alt!(
-    do_parse!(
-        punct!("//!") >>
-        s: take_until_newline_or_eof!() >>
-        ((s, true))
-    )
-    |
-    do_parse!(
-        option!(whitespace) >>
-        peek!(tag!("/*!")) >>
-        s: block_comment >>
-        ((s, true))
-    )
-    |
-    do_parse!(
-        punct!("///") >>
-        not!(tag!("/")) >>
-        s: take_until_newline_or_eof!() >>
-        ((s, false))
-    )
-    |
-    do_parse!(
-        option!(whitespace) >>
-        peek!(pair!(tag!("/**"), not!(tag!("*")))) >>
-        s: block_comment >>
-        ((s, false))
-    )
-));
+fn doc_comment_contents(input: Cursor) -> PResult<(&str, bool)> {
+    let input = skip_whitespace(input);
+    if input.starts_with("//!") {
+        let input = input.advance(3);
+        let (input, s) = take_until_newline_or_eof(input);
+        Ok((input, (s, true)))
+    } else if input.starts_with("/*!") {
+        let (input, s) = block_comment(input)?;
+        Ok((input, (s, true)))
+    } else if input.starts_with("///") {
+        let input = input.advance(3);
+        if input.starts_with("/") {
+            return Err(LexError);
+        }
+        let (input, s) = take_until_newline_or_eof(input);
+        Ok((input, (s, false)))
+    } else if input.starts_with("/**") && !input.advance(3).starts_with("*") {
+        let (input, s) = block_comment(input)?;
+        Ok((input, (s, false)))
+    } else {
+        Err(LexError)
+    }
+}
+
+fn take_until_newline_or_eof(input: Cursor) -> (Cursor, &str) {
+    match input.find('\n') {
+        Some(i) => (input.advance(i), &input.rest[..i]),
+        None => (input.advance(input.len()), input.rest),
+    }
+}

src/strnom.rs

@@ -237,15 +237,6 @@ macro_rules! do_parse {
     };
 }
 
-macro_rules! peek {
-    ($i:expr, $submac:ident!( $($args:tt)* )) => {
-        match $submac!($i, $($args)*) {
-            Ok((_, o)) => Ok(($i, o)),
-            Err(LexError) => Err(LexError),
-        }
-    };
-}
-
 macro_rules! call {
     ($i:expr, $fun:expr $(, $args:expr)*) => {
         $fun($i $(, $args)*)
@@ -261,36 +252,6 @@ macro_rules! option {
     };
 }
 
-macro_rules! take_until_newline_or_eof {
-    ($i:expr,) => {
-        match $i.find('\n') {
-            Some(i) => Ok(($i.advance(i), &$i.rest[..i])),
-            None => Ok(($i.advance($i.len()), $i.rest)),
-        }
-    };
-}
-
-macro_rules! pair {
-    ($i:expr, $first:ident!( $($arg1:tt)* ), $second:ident!( $($arg2:tt)* )) => {
-        match $first!($i, $($arg1)*) {
-            Err(LexError) => Err(LexError),
-            Ok((i, o1)) => match $second!(i, $($arg2)*) {
-                Err(LexError) => Err(LexError),
-                Ok((i, o2)) => Ok((i, (o1, o2))),
-            },
-        }
-    };
-}
-
-macro_rules! not {
-    ($i:expr, $submac:ident!( $($args:tt)* )) => {
-        match $submac!($i, $($args)*) {
-            Ok((_, _)) => Err(LexError),
-            Err(LexError) => Ok(($i, ())),
-        }
-    };
-}
-
 macro_rules! tag {
     ($i:expr, $tag:expr) => {
         if $i.starts_with($tag) {