tamer: asg::graph::object: ObjectIndex::try_map_obj_inner

Continuing to clean house and make things more concise, not just for `tpl`
but for all future changes.

DEV-13163

tamer/src/asg/graph/object.rs

@@ -123,7 +123,7 @@ use super::{Asg, AsgError};
 use crate::{
     diagnose::{panic::DiagnosticPanic, Annotate, AnnotatedSpan},
     diagnostic_panic,
-    f::Map,
+    f::{Map, TryMap},
     parse::util::SPair,
     span::{Span, UNKNOWN_SPAN},
 };
@@ -735,6 +735,26 @@ impl<O: ObjectKind> ObjectIndex<O> {
         asg.try_map_obj(self, f)
     }
 
+    /// Resolve the identifier and map over an inner `T` of the resulting
+    ///   [`Object`] narrowed to [`ObjectKind`] `O`,
+    ///     replacing the object on the given [`Asg`].
+    ///
+    /// This uses [`Self::try_map_obj`] to retrieve the object from
+    ///   the [`Asg`].
+    ///
+    /// If this operation is [`Infallible`],
+    ///   see [`Self::map_obj_inner`].
+    pub fn try_map_obj_inner<T, E>(
+        self,
+        asg: &mut Asg,
+        f: impl FnOnce(T) -> <O as TryMap<T>>::FnResult<E>,
+    ) -> Result<Self, E>
+    where
+        O: TryMap<T, Result<E> = Result<O, (O, E)>>,
+    {
+        self.try_map_obj(asg, O::try_fmap(f))
+    }
+
     /// Resolve the identifier and infallibly map over the resulting
     ///   [`Object`] narrowed to [`ObjectKind`] `O`,
     ///     replacing the object on the given [`Asg`].
@@ -751,6 +771,22 @@ impl<O: ObjectKind> ObjectIndex<O> {
         }
     }
 
+    /// Resolve the identifier and map over an inner `T` of the resulting
+    ///   [`Object`] narrowed to [`ObjectKind`] `O`,
+    ///     replacing the object on the given [`Asg`].
+    ///
+    /// This uses [`Self::map_obj`] to retrieve the object from
+    ///   the [`Asg`].
+    ///
+    /// If this operation is _not_ [`Infallible`],
+    ///   see [`Self::try_map_obj_inner`].
+    pub fn map_obj_inner<T>(self, asg: &mut Asg, f: impl FnOnce(T) -> T) -> Self
+    where
+        O: Map<T, Target = O>,
+    {
+        self.map_obj(asg, O::fmap(f))
+    }
+
     /// Lift [`Self`] into [`Option`] and [`filter`](Option::filter) based
     ///   on whether the [`ObjectRelatable::rel_ty`] of [`Self`]'s `O`
     ///   matches that of `OB`.

tamer/src/asg/graph/object/tpl.rs

@@ -22,11 +22,7 @@
 use std::fmt::Display;
 
 use super::{prelude::*, Doc, Expr, Ident};
-use crate::{
-    f::{Map, TryMap},
-    parse::util::SPair,
-    span::Span,
-};
+use crate::{f::Map, parse::util::SPair, span::Span};
 
 /// Template with associated name.
 #[derive(Debug, PartialEq, Eq)]
@@ -193,6 +189,17 @@ impl TplShape {
     }
 }
 
+/// Attempt to adapt a template shape to that of another.
+///
+/// This returns a partially applied [`TplShape::try_adapt_to`],
+///   where the remaining argument is `self`.
+fn try_adapt_to(
+    other: TplShape,
+    tpl_name: Option<SPair>,
+) -> impl FnOnce(TplShape) -> Result<TplShape, (TplShape, AsgError)> {
+    move |s| s.try_adapt_to(other, tpl_name)
+}
+
 impl Display for TplShape {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         // phrase as "template with ..."
@@ -221,11 +228,10 @@ object_rel! {
                 let tpl_name = from_oi.name(asg);
                 let span = to_oi.resolve(asg).span();
 
-                from_oi.try_map_obj(asg, |tpl| {
-                    tpl.try_map(|shape: TplShape| {
-                        shape.try_adapt_to(TplShape::Expr(span), tpl_name)
-                    })
-                })?;
+                from_oi.try_map_obj_inner(
+                    asg,
+                    try_adapt_to(TplShape::Expr(span), tpl_name),
+                )?;
 
                 Ok(commit(asg))
             }
@@ -250,12 +256,10 @@ object_rel! {
                     .shape()
                     .overwrite_span_if_any(apply.span());
 
-                // TODO: Refactor; very similar to Expr edge above.
-                from_oi.try_map_obj(asg, |tpl| {
-                    tpl.try_map(|shape: TplShape| {
-                        shape.try_adapt_to(apply_shape, tpl_name)
-                    })
-                })?;
+                from_oi.try_map_obj_inner(
+                    asg,
+                    try_adapt_to(apply_shape, tpl_name),
+                )?;
 
                 Ok(commit(asg))
             }