1 files changed, 43 insertions, 0 deletions
diff --git a/rprt-engine/src/selection_function.rs b/rprt-engine/src/selection_function.rs
new file mode 100644
index 0000000..6f05650
--- /dev/null
+++ b/rprt-engine/src/selection_function.rs
@@ -0,0 +1,43 @@
+use crate::buffer::BufferID;
+use crate::selection::{Interval, Selection, VectoriseError};
+use crate::state::EditorState;
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum SFError {}
+
+struct SFComponents {
+    niladic: Box<dyn Fn(&EditorState) -> Result<Selection, SFError>>,
+    monadic_rank0: Box<dyn Fn(&EditorState, &BufferID, usize) -> Result<Selection, SFError>>,
+    monadic_rank1: Box<dyn Fn(&EditorState, &BufferID, &Interval) -> Result<Selection, SFError>>,
+    dyadic: Option<Box<dyn Fn(&EditorState, &Selection, &Selection) -> Result<Selection, SFError>>>,
+}
+
+pub struct SelectionFunction<E> {
+    niladic: Box<dyn Fn(&EditorState) -> Result<Selection, E>>,
+    monadic: Box<dyn Fn(&EditorState, &Selection) -> Result<Selection, E>>,
+    dyadic: Option<Box<dyn Fn(&EditorState, &Selection, &Selection) -> Result<Selection, E>>>,
+}
+
+impl From<SFComponents> for SelectionFunction<VectoriseError<SFError>> {
+    fn from(sfc: SFComponents) -> Self {
+        let dyadic: Option<Box<dyn Fn(&EditorState, &Selection, &Selection) -> _>> =
+            if let Some(func) = sfc.dyadic {
+                Some(Box::new(
+                    move |editor_state: &EditorState, left: &Selection, right: &Selection| {
+                        (func)(editor_state, left, right).map_err(VectoriseError::ProcessingError)
+                    },
+                ))
+            } else {
+                None
+            };
+
+        Self {
+            niladic: Box::new(move |editor_state: &EditorState| {
+                (sfc.niladic)(editor_state).map_err(VectoriseError::ProcessingError)
+            }),
+            monadic: Box::new(Selection::vectorise(sfc.monadic_rank0, sfc.monadic_rank1)),
+            dyadic: dyadic,
+        }
+    }
+}