divide atom parser into sub-parsers with context

src/bng/score/lex/lexer.rs

@@ -16,8 +16,6 @@ use nom::{
     Err, IResult, Parser,
 };
 
-use crate::bng::score::{modifier, quick_modifier, slope_modifier};
-
 use super::{
     super::super::Expression as Instruction, Atom, FlatAtom, Modifier, QuickModifier, SlopeModifier,
 };
@@ -45,21 +43,61 @@ where
     ))(i)
 }
 
-fn atom<'a, E>(notes: &'a str) -> impl Parser<&'a str, FlatAtom, E>
+fn note<'a, E>(notes: &'a str) -> impl Parser<&'a str, FlatAtom, E>
 where
-    E: ParseError<&'a str>
-        + ContextError<&'a str>
-        + FromExternalError<&'a str, TryFromIntError>
-        + FromExternalError<&'a str, E>,
+    E: ParseError<&'a str> + ContextError<&'a str> + FromExternalError<&'a str, TryFromIntError>,
 {
     context(
-        "atom",
-        alt((
+        "note",
         map_res(map_opt(one_of(notes), |c| notes.find(c)), u8::try_from).map(FlatAtom::Note),
-            value(FlatAtom::Rest, char(Atom::REST)),
+    )
+}
+
+fn rest<'a, E>(i: &'a str) -> IResult<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str> + ContextError<&'a str>,
+{
+    context("rest", value(FlatAtom::Rest, char(Atom::REST)))(i)
+}
+
+fn start_here<'a, E>(i: &'a str) -> IResult<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str> + ContextError<&'a str>,
+{
+    context(
+        "start_here",
         value(FlatAtom::StartHere, char(Atom::START_HERE)),
+    )(i)
+}
+
+fn modifier<'a, E>(i: &'a str) -> IResult<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str> + ContextError<&'a str>,
+{
+    use super::super::modifier;
+    context(
+        "modifier",
         preceded(char(Atom::MODIFIER), modifier).map(FlatAtom::Modifier),
+    )(i)
+}
+
+fn quick_modifier<'a, E>(i: &'a str) -> IResult<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str> + ContextError<&'a str>,
+{
+    use super::super::quick_modifier;
+    context(
+        "quick_modifier",
         quick_modifier.map(FlatAtom::QuickModifier),
+    )(i)
+}
+
+fn loop_starts<'a, E>(i: &'a str) -> IResult<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str> + ContextError<&'a str>,
+{
+    context(
+        "loop_starts",
         preceded(
             char(Atom::LOOP.0),
             map_opt(opt(u8), |n| {
@@ -71,9 +109,43 @@ where
             }),
         )
         .map(FlatAtom::LoopStarts),
-            value(FlatAtom::LoopEnds, char(Atom::LOOP.1)),
+    )(i)
+}
+
+fn loop_ends<'a, E>(i: &'a str) -> IResult<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str> + ContextError<&'a str>,
+{
+    context("loop_ends", value(FlatAtom::LoopEnds, char(Atom::LOOP.1)))(i)
+}
+
+fn tuple_starts<'a, E>(i: &'a str) -> IResult<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str> + ContextError<&'a str>,
+{
+    context(
+        "tuple_starts",
         value(FlatAtom::TupleStarts, char(Atom::TUPLE.0)),
+    )(i)
+}
+
+fn tuple_ends<'a, E>(i: &'a str) -> IResult<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str> + ContextError<&'a str>,
+{
+    context(
+        "tuple_ends",
         value(FlatAtom::TupleEnds, char(Atom::TUPLE.1)),
+    )(i)
+}
+
+fn slope_starts<'a, E>(i: &'a str) -> IResult<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str> + ContextError<&'a str> + FromExternalError<&'a str, E>,
+{
+    use super::super::slope_modifier;
+    context(
+        "slope_starts",
         terminated(
             preceded(
                 char(Atom::SLOPE.0),
@@ -89,7 +161,25 @@ where
             char(','),
         )
         .map(|(sm, i)| FlatAtom::SlopeStarts(sm, i)),
+    )(i)
+}
+
+fn slope_ends<'a, E>(i: &'a str) -> IResult<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str> + ContextError<&'a str>,
+{
+    context(
+        "slope_ends",
         value(FlatAtom::SlopeEnds, char(Atom::SLOPE.1)),
+    )(i)
+}
+
+fn comment<'a, E>(i: &'a str) -> IResult<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str> + ContextError<&'a str>,
+{
+    context(
+        "comment",
         value(
             FlatAtom::Comment,
             delimited(
@@ -98,6 +188,31 @@ where
                 char(Atom::COMMENT.1),
             ),
         ),
+    )(i)
+}
+
+fn atom<'a, E>(notes: &'a str) -> impl Parser<&'a str, FlatAtom, E>
+where
+    E: ParseError<&'a str>
+        + ContextError<&'a str>
+        + FromExternalError<&'a str, TryFromIntError>
+        + FromExternalError<&'a str, E>,
+{
+    context(
+        "atom",
+        alt((
+            note(notes),
+            rest,
+            start_here,
+            modifier,
+            quick_modifier,
+            loop_starts,
+            loop_ends,
+            tuple_starts,
+            tuple_ends,
+            slope_starts,
+            slope_ends,
+            comment,
         )),
     )
 }