From 2c96e1c6de13821558b5aa40212a0eb7b1b6856f Mon Sep 17 00:00:00 2001
From: John Turner <jturner.usa@gmail.com>
Date: Fri, 31 Oct 2025 22:00:42 +0000
Subject: create ParserIter trait

---
 src/lib.rs | 354 ++++++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 235 insertions(+), 119 deletions(-)

(limited to 'src/lib.rs')

diff --git a/src/lib.rs b/src/lib.rs
index 250ce9f..7221769 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,7 +6,7 @@ use core::{
     fmt,
     iter::{IntoIterator, Iterator},
     marker::Sized,
-    ops::{Bound, Range, RangeBounds},
+    ops::Range,
 };
 
 use crate::{
@@ -153,16 +153,6 @@ pub trait Parser<I: Input>: Sized {
         Recognize { parser: self }
     }
 
-    fn repeated<R>(self, range: R) -> impl Parser<I, Output = Vec<Self::Output>>
-    where
-        R: RangeBounds<usize>,
-    {
-        Repeated {
-            parser: self,
-            range,
-        }
-    }
-
     fn verify_input<C>(self, checker: C) -> impl Parser<I, Output = Self::Output>
     where
         C: Parser<I>,
@@ -195,23 +185,228 @@ pub trait Parser<I: Input>: Sized {
         Not { parser: self }
     }
 
-    fn separated_by<P, R>(
-        self,
-        delimiter: P,
-        range: R,
-    ) -> impl Parser<I, Output = Vec<Self::Output>>
+    fn repeated(self) -> impl ParserIter<I, Item = Self::Output> {
+        Repeated { parser: self }
+    }
+
+    fn separated_by<P>(self, delimiter: P) -> impl ParserIter<I, Item = Self::Output>
     where
         P: Parser<I>,
-        R: RangeBounds<usize>,
     {
         SeparatedBy {
             parser: self,
             delimiter,
-            range,
         }
     }
 }
 
+pub trait ParserIter<I: Input> {
+    type Item;
+
+    fn next<OM: Mode, EM: Mode>(
+        &self,
+        it: InputIter<I>,
+    ) -> Option<ParserResult<I, Self::Item, OM, EM>>;
+
+    fn many(self) -> impl Parser<I, Output = Vec<Self::Item>>
+    where
+        Self: Sized,
+    {
+        Many { parser: self }
+    }
+
+    fn at_least(self, count: usize) -> impl Parser<I, Output = Vec<Self::Item>>
+    where
+        Self: Sized,
+    {
+        AtLeast {
+            parser: self,
+            count,
+        }
+    }
+
+    fn at_most(self, count: usize) -> impl Parser<I, Output = Vec<Self::Item>>
+    where
+        Self: Sized,
+    {
+        AtMost {
+            parser: self,
+            count,
+        }
+    }
+}
+
+struct Repeated<P> {
+    parser: P,
+}
+
+impl<I, P> ParserIter<I> for Repeated<P>
+where
+    I: Input,
+    P: Parser<I>,
+{
+    type Item = P::Output;
+
+    fn next<OM: Mode, EM: Mode>(
+        &self,
+        it: InputIter<I>,
+    ) -> Option<ParserResult<I, Self::Item, OM, EM>> {
+        if it.is_finished() {
+            None
+        } else {
+            match self.parser.run::<OM, EM, ()>(it) {
+                Ok((rest, output)) => Some(Ok((rest, output))),
+                Err(rest) => Some(Err(rest)),
+            }
+        }
+    }
+}
+
+struct SeparatedBy<P1, P2> {
+    parser: P1,
+    delimiter: P2,
+}
+
+impl<I, P1, P2> ParserIter<I> for SeparatedBy<P1, P2>
+where
+    I: Input,
+    P1: Parser<I>,
+    P2: Parser<I>,
+{
+    type Item = P1::Output;
+
+    fn next<OM: Mode, EM: Mode>(
+        &self,
+        it: InputIter<I>,
+    ) -> Option<ParserResult<I, Self::Item, OM, EM>> {
+        if it.is_finished() {
+            None
+        } else {
+            let (rest, output) = match self.parser.run::<OM, EM, ()>(it) {
+                Ok((rest, output)) => (rest, output),
+                Err(rest) => return Some(Err(rest)),
+            };
+
+            let rest = match self.delimiter.check(rest.clone()) {
+                Ok((rest, _)) => rest,
+                _ => rest,
+            };
+
+            Some(Ok((rest, output)))
+        }
+    }
+}
+
+struct AtLeast<P> {
+    parser: P,
+    count: usize,
+}
+
+impl<I, P> Parser<I> for AtLeast<P>
+where
+    I: Input,
+    P: ParserIter<I>,
+{
+    type Output = Vec<P::Item>;
+
+    fn run<OM: Mode, EM: Mode, Tracer: Trace<I>>(
+        &self,
+        mut it: InputIter<I>,
+    ) -> ParserResult<I, Self::Output, OM, EM> {
+        let mut outputs = OM::bind(|| Vec::new());
+        let mut i = 0;
+
+        while !it.is_finished() {
+            it = match self.parser.next::<OM, EM>(it.clone()) {
+                Some(Ok((rest, output))) => {
+                    outputs = OM::combine(outputs, output, |mut acc, e| {
+                        acc.push(e);
+                        acc
+                    });
+                    rest
+                }
+                Some(Err(_)) if i >= self.count => break,
+                Some(Err(rest)) => return Err(rest),
+                None if i >= self.count => break,
+                None => return Err(EM::bind(|| it)),
+            };
+
+            i += 1;
+        }
+
+        Ok((it, outputs))
+    }
+}
+
+struct AtMost<P> {
+    parser: P,
+    count: usize,
+}
+
+impl<I, P> Parser<I> for AtMost<P>
+where
+    I: Input,
+    P: ParserIter<I>,
+{
+    type Output = Vec<P::Item>;
+
+    fn run<OM: Mode, EM: Mode, Tracer: Trace<I>>(
+        &self,
+        mut it: InputIter<I>,
+    ) -> ParserResult<I, Self::Output, OM, EM> {
+        let mut outputs = OM::bind(|| Vec::new());
+
+        for _ in 0..self.count {
+            it = match self.parser.next::<OM, EM>(it.clone()) {
+                Some(Ok((rest, output))) => {
+                    outputs = OM::combine(outputs, output, |mut acc, e| {
+                        acc.push(e);
+                        acc
+                    });
+                    rest
+                }
+                _ => break,
+            }
+        }
+
+        Ok((it, outputs))
+    }
+}
+
+struct Many<P> {
+    parser: P,
+}
+
+impl<I, P> Parser<I> for Many<P>
+where
+    I: Input,
+    P: ParserIter<I>,
+{
+    type Output = Vec<P::Item>;
+
+    fn run<OM: Mode, EM: Mode, Tracer: Trace<I>>(
+        &self,
+        mut it: InputIter<I>,
+    ) -> ParserResult<I, Self::Output, OM, EM> {
+        let mut outputs = OM::bind(|| Vec::new());
+
+        while !it.is_finished() {
+            it = match self.parser.next::<OM, EM>(it.clone()) {
+                Some(Ok((rest, output))) => {
+                    outputs = OM::combine(outputs, output, |mut acc, e| {
+                        acc.push(e);
+                        acc
+                    });
+                    rest
+                }
+                _ => break,
+            };
+        }
+
+        Ok((it, outputs))
+    }
+}
+
 impl<I, O, F> Parser<I> for F
 where
     I: Input,
@@ -387,98 +582,6 @@ where
     Take { amt }
 }
 
-struct Repeated<P, R> {
-    parser: P,
-    range: R,
-}
-
-impl<I, P, R> Parser<I> for Repeated<P, R>
-where
-    I: Input,
-    P: Parser<I>,
-    R: RangeBounds<usize>,
-{
-    type Output = Vec<P::Output>;
-
-    fn run<OM: Mode, EM: Mode, Tracer: Trace<I>>(
-        &self,
-        mut it: InputIter<I>,
-    ) -> ParserResult<I, Self::Output, OM, EM> {
-        Tracer::trace("list", it.clone());
-
-        let mut outputs = OM::bind(|| Vec::new());
-        let mut i = 0;
-
-        while (Bound::Unbounded, self.range.end_bound()).contains(&i) {
-            it = match self.parser.run::<OM, EM, Tracer>(it.clone()) {
-                Ok((rest, output)) => {
-                    outputs = OM::combine(outputs, output, |mut acc, e| {
-                        acc.push(e);
-                        acc
-                    });
-                    rest
-                }
-                Err(_) if self.range.contains(&i) => break,
-                Err(rest) => return Err(rest),
-            };
-
-            i += 1;
-        }
-
-        Ok((it, outputs))
-    }
-}
-
-struct SeparatedBy<P1, P2, R> {
-    parser: P1,
-    delimiter: P2,
-    range: R,
-}
-
-impl<I, P1, P2, R> Parser<I> for SeparatedBy<P1, P2, R>
-where
-    I: Input,
-    P1: Parser<I>,
-    P2: Parser<I>,
-    R: RangeBounds<usize>,
-{
-    type Output = Vec<P1::Output>;
-
-    fn run<OM: Mode, EM: Mode, Tracer: Trace<I>>(
-        &self,
-        mut it: InputIter<I>,
-    ) -> ParserResult<I, Self::Output, OM, EM> {
-        Tracer::trace("separated list", it.clone());
-
-        let mut outputs = OM::bind(|| Vec::new());
-        let mut i = 0usize;
-
-        while (Bound::Unbounded, self.range.end_bound()).contains(&i) {
-            it = match self.parser.run::<OM, EM, Tracer>(it.clone()) {
-                Ok((rest, output)) => {
-                    outputs = OM::combine(outputs, output, |mut acc, e| {
-                        acc.push(e);
-                        acc
-                    });
-                    rest
-                }
-                _ if self.range.contains(&i) => break,
-                _ => return Err(EM::bind(|| it)),
-            };
-
-            i += 1;
-
-            it = match self.delimiter.check(it.clone()) {
-                Ok((rest, _)) => rest,
-                _ if self.range.contains(&i) => break,
-                _ => return Err(EM::bind(|| it)),
-            };
-        }
-
-        Ok((it, outputs))
-    }
-}
-
 pub struct OneOf<It> {
     it: It,
 }
@@ -861,7 +964,8 @@ where
     I::Item: Character,
 {
     r#if(|c: &I::Item| c.is_alphabetic())
-        .repeated(0..)
+        .repeated()
+        .many()
         .recognize()
 }
 
@@ -871,7 +975,8 @@ where
     I::Item: Character,
 {
     r#if(|c: &I::Item| c.is_alphabetic())
-        .repeated(1..)
+        .repeated()
+        .at_least(1)
         .recognize()
 }
 
@@ -880,7 +985,10 @@ where
     I: Input,
     I::Item: Character,
 {
-    r#if(|c: &I::Item| c.is_numeric()).repeated(0..).recognize()
+    r#if(|c: &I::Item| c.is_numeric())
+        .repeated()
+        .many()
+        .recognize()
 }
 
 pub fn numeric1<I>() -> impl Parser<I, Output = I>
@@ -888,7 +996,10 @@ where
     I: Input,
     I::Item: Character,
 {
-    r#if(|c: &I::Item| c.is_numeric()).repeated(1..).recognize()
+    r#if(|c: &I::Item| c.is_numeric())
+        .repeated()
+        .at_least(1)
+        .recognize()
 }
 
 pub fn alphanumeric<I>() -> impl Parser<I, Output = I>
@@ -897,7 +1008,8 @@ where
     I::Item: Character,
 {
     r#if(|c: &I::Item| c.is_alphanumeric())
-        .repeated(0..)
+        .repeated()
+        .many()
         .recognize()
 }
 
@@ -907,7 +1019,8 @@ where
     I::Item: Character,
 {
     r#if(|c: &I::Item| c.is_alphanumeric())
-        .repeated(1..)
+        .repeated()
+        .at_least(1)
         .recognize()
 }
 
@@ -917,7 +1030,8 @@ where
     I::Item: Character,
 {
     r#if(|c: &I::Item| c.is_whitespace())
-        .repeated(0..)
+        .repeated()
+        .many()
         .recognize()
 }
 
@@ -927,7 +1041,8 @@ where
     I::Item: Character,
 {
     r#if(|c: &I::Item| c.is_whitespace())
-        .repeated(1..)
+        .repeated()
+        .at_least(1)
         .recognize()
 }
 
@@ -977,7 +1092,8 @@ mod test {
         let it = InputIter::new(input);
 
         alpha1()
-            .separated_by(whitespace(), 1..)
+            .separated_by(whitespace())
+            .at_least(1)
             .check_finished(it)
             .unwrap();
     }
-- 
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