Migrated AndThenParser to MapDecorator

Author: ngeor

rusty_pc/src/and_then.rs

@@ -1,3 +1,4 @@
+use crate::map_decorator::{MapDecorator, MapDecoratorMarker};
 use crate::{InputTrait, Parser};
 
 pub struct AndThenParser<P, F> {
@@ -11,19 +12,25 @@ impl<P, F> AndThenParser<P, F> {
     }
 }
 
-impl<I, C, P, F, U> Parser<I, C> for AndThenParser<P, F>
+impl<I, C, P, F, U> MapDecorator<I, C> for AndThenParser<P, F>
 where
     I: InputTrait,
     P: Parser<I, C>,
     F: Fn(P::Output) -> Result<U, P::Error>,
 {
+    type OriginalOutput = P::Output;
     type Output = U;
     type Error = P::Error;
-    fn parse(&mut self, tokenizer: &mut I) -> Result<Self::Output, Self::Error> {
-        self.parser.parse(tokenizer).and_then(&self.mapper)
+
+    fn decorated(
+        &mut self,
+    ) -> &mut impl Parser<I, C, Output = Self::OriginalOutput, Error = Self::Error> {
+        &mut self.parser
     }
 
-    fn set_context(&mut self, ctx: &C) {
-        self.parser.set_context(ctx)
+    fn map_ok(&self, ok: Self::OriginalOutput) -> Result<Self::Output, Self::Error> {
+        (self.mapper)(ok)
     }
 }
+
+impl<P, F> MapDecoratorMarker for AndThenParser<P, F> {}

rusty_pc/src/and_then_err.rs

@@ -28,8 +28,8 @@ where
         &mut self.parser
     }
 
-    fn map_ok(&self, ok: Self::OriginalOutput) -> Self::Output {
-        ok
+    fn map_ok(&self, ok: Self::OriginalOutput) -> Result<Self::Output, Self::Error> {
+        Ok(ok)
     }
 
     fn map_soft_error(&self, err: Self::Error) -> Result<Self::Output, Self::Error> {

rusty_pc/src/map.rs

@@ -26,8 +26,8 @@ where
         &mut self.parser
     }
 
-    fn map_ok(&self, ok: P::Output) -> U {
-        (self.mapper)(ok)
+    fn map_ok(&self, ok: P::Output) -> Result<Self::Output, Self::Error> {
+        Ok((self.mapper)(ok))
     }
 }
 
@@ -57,7 +57,9 @@ where
         &mut self.parser
     }
 
-    fn map_ok(&self, _ok: P::Output) {}
+    fn map_ok(&self, _ok: P::Output) -> Result<Self::Output, Self::Error> {
+        Ok(())
+    }
 }
 
 impl<P> MapDecoratorMarker for MapToUnitParser<P> {}

rusty_pc/src/map_decorator.rs

@@ -1,6 +1,8 @@
 use crate::{InputTrait, Parser, ParserErrorTrait};
 
-/// A parser decorator that maps the result of the decorated parser.
+/// A parser decorator that maps the successful result
+/// and optionally the soft error
+/// of the decorated parser.
 pub trait MapDecorator<I, C>
 where
     I: InputTrait,
@@ -15,7 +17,7 @@ where
     ) -> &mut impl Parser<I, C, Output = Self::OriginalOutput, Error = Self::Error>;
 
     /// Maps the successful result of the parser.
-    fn map_ok(&self, ok: Self::OriginalOutput) -> Self::Output;
+    fn map_ok(&self, ok: Self::OriginalOutput) -> Result<Self::Output, Self::Error>;
 
     /// Maps the soft error of the parser.
     /// By default, the error is returned as-is. However, it is possible to override this behavior.
@@ -38,7 +40,7 @@ where
 
     fn parse(&mut self, input: &mut I) -> Result<Self::Output, Self::Error> {
         match self.decorated().parse(input) {
-            Ok(ok) => Ok(self.map_ok(ok)),
+            Ok(ok) => self.map_ok(ok),
             Err(err) if err.is_soft() => self.map_soft_error(err),
             Err(err) => Err(err),
         }

rusty_pc/src/or_default.rs

@@ -27,8 +27,8 @@ where
         &mut self.parser
     }
 
-    fn map_ok(&self, ok: Self::OriginalOutput) -> Self::Output {
-        ok
+    fn map_ok(&self, ok: Self::OriginalOutput) -> Result<Self::Output, Self::Error> {
+        Ok(ok)
     }
 
     fn map_soft_error(&self, _err: Self::Error) -> Result<Self::Output, Self::Error> {

rusty_pc/src/to_option.rs

@@ -26,8 +26,8 @@ where
         &mut self.parser
     }
 
-    fn map_ok(&self, ok: Self::OriginalOutput) -> Self::Output {
-        Some(ok)
+    fn map_ok(&self, ok: Self::OriginalOutput) -> Result<Self::Output, Self::Error> {
+        Ok(Some(ok))
     }
 
     fn map_soft_error(&self, _err: Self::Error) -> Result<Self::Output, Self::Error> {