add the value combinator as a function

src/combinator/macros.rs

@@ -683,19 +683,10 @@ macro_rules! verify (
 #[macro_export(local_inner_macros)]
 macro_rules! value (
   ($i:expr, $res:expr, $submac:ident!( $($args:tt)* )) => (
-    {
-      use $crate::lib::std::result::Result::*;
-
-      match $submac!($i, $($args)*) {
-        Ok((i,_)) => {
-          Ok((i, $res))
-        },
-        Err(e) => Err(e),
-      }
-    }
+    $crate::combinator::valuec($i, $res, |i| $submac!(i, $($args)*))
   );
   ($i:expr, $res:expr, $f:expr) => (
-    value!($i, $res, call!($f))
+    $crate::combinator::valuec($i, $res, $f)
   );
   ($i:expr, $res:expr) => (
     {

src/combinator/mod.rs

@@ -486,6 +486,38 @@ where
   verify(first, second)(input)
 }
 
+/// returns the provided value if the child parser succeeds
+///
+/// ```rust
+/// # #[macro_use] extern crate nom;
+/// # use nom::{Err,error::ErrorKind, IResult};
+/// use nom::combinator::value;
+/// use nom::character::complete::alpha1;
+/// # fn main() {
+///
+/// let parser = value(1234, alpha1);
+///
+/// assert_eq!(parser("abcd"), Ok(("", 1234)));
+/// assert_eq!(parser("123abcd;"), Err(Err::Error(("123abcd;", ErrorKind::Alpha))));
+/// # }
+/// ```
+pub fn value<I, O1: Clone, O2, E: ParseError<I>, F>(val: O1, parser: F) -> impl Fn(I) -> IResult<I, O1, E>
+where
+  F: Fn(I) -> IResult<I, O2, E>,
+{
+  move |input: I| {
+    parser(input).map(|(i, _)| (i, val.clone()))
+  }
+}
+
+#[doc(hidden)]
+pub fn valuec<I, O1: Clone, O2, E: ParseError<I>, F>(input: I, val: O1, parser: F) -> IResult<I, O1, E>
+where
+  F: Fn(I) -> IResult<I, O2, E>,
+{
+  value(val, parser)(input)
+}
+
 /// succeeds if the child parser returns an error
 ///
 /// ```rust