backup commit

src/utils/mod.rs

@@ -2,8 +2,13 @@ mod cache;
 mod substack;
 mod side;
 mod merge_sorted;
-mod unwrap_or_continue;
+mod unwrap_or;
 pub mod iter;
+mod bfs;
+mod unless_let;
+mod string_from_charset;
+mod for_loop;
+mod protomap;
 
 pub use cache::Cache;
 use mappable_rc::Mrc;
@@ -11,6 +16,7 @@ pub use substack::Stackframe;
 pub use side::Side;
 pub use merge_sorted::merge_sorted;
 pub use iter::BoxedIter;
+pub use string_from_charset::string_from_charset;
 
 pub fn mrc_derive<T: ?Sized, P, U: ?Sized>(m: &Mrc<T>, p: P) -> Mrc<U>
 where P: for<'a> FnOnce(&'a T) -> &'a U {
@@ -37,3 +43,31 @@ pub fn mrc_derive_slice<T>(mv: &Mrc<Vec<T>>) -> Mrc<[T]> {
 pub fn one_mrc_slice<T>(t: T) -> Mrc<[T]> {
     Mrc::map(Mrc::new([t; 1]), |v| v.as_slice())
 }
+
+pub fn mrc_to_iter<T>(ms: Mrc<[T]>) -> impl Iterator<Item = Mrc<T>> {
+    let mut i = 0;
+    std::iter::from_fn(move || if i < ms.len() {
+        let out = Some(mrc_derive(&ms, |s| &s[i]));
+        i += 1;
+        out
+    } else {None})
+}
+
+pub fn mrc_unnest<T>(m: &Mrc<Mrc<T>>) -> Mrc<T> {
+    Mrc::clone(m.as_ref())
+}
+
+pub fn mrc_slice_to_only<T>(m: Mrc<[T]>) -> Result<Mrc<T>, ()> {
+    Mrc::try_map(m, |slice| {
+        if slice.len() != 1 {None}
+        else {Some(&slice[0])}
+    }).map_err(|_| ())
+}
+
+pub fn mrc_slice_to_only_option<T>(m: Mrc<[T]>) -> Result<Option<Mrc<T>>, ()> {
+    if m.len() > 1 {return Err(())}
+    Ok(Mrc::try_map(m, |slice| {
+        if slice.len() == 0 {None}
+        else {Some(&slice[0])}
+    }).ok())
+}