Refactor selection functions into a module, one function per file

1 files changed, 77 insertions, 0 deletions

diff --git a/rprt-engine/src/selection_functions/result_transformation.rs b/rprt-engine/src/selection_functions/result_transformation.rs
new file mode 100644
index 0000000..89a071a
--- /dev/null
+++ b/rprt-engine/src/selection_functions/result_transformation.rs
@@ -0,0 +1,77 @@
+use crate::buffer::BufferID;
+use crate::selection::{Interval, Selection};
+use crate::selection_functions::types::{SFArguments, SFError, SFResult};
+use crate::state::EditorState;
+
+pub fn complement_transform(es: &EditorState, result: Selection, _: &SFArguments) -> SFResult {
+    fn complement_rank0(
+        es: &EditorState,
+        buffer_id: BufferID,
+        pos: usize,
+    ) -> Result<Selection, SFError> {
+        if let Some(buf) = es.get_buffer(buffer_id) {
+            let mut ranges = Vec::new();
+            if pos > 0 {
+                ranges.push(Interval::new(0, pos));
+            }
+            let max_pos = buf.max_pos();
+            if pos + 1 < max_pos {
+                ranges.push(Interval::new(pos + 1, max_pos));
+            }
+            Ok(Selection::Ranges { buffer_id, ranges })
+        } else {
+            Err(SFError::BufferNotFound(buffer_id))
+        }
+    }
+
+    fn complement_rank1(
+        es: &EditorState,
+        buffer_id: BufferID,
+        interval: &Interval,
+    ) -> Result<Selection, SFError> {
+        if let Some(buf) = es.get_buffer(buffer_id) {
+            let max_pos = buf.max_pos();
+            if interval.start == 0 && interval.end >= max_pos {
+                return Ok(Selection::empty());
+            }
+
+            let mut ranges = Vec::new();
+            if interval.start == 0 {
+                if interval.end < max_pos {
+                    ranges.push(Interval::new(interval.end, max_pos));
+                }
+            } else if interval.end == max_pos {
+                ranges.push(Interval::new(0, interval.start));
+            } else {
+                ranges.push(Interval::new(0, interval.start));
+                ranges.push(Interval::new(interval.end, max_pos));
+            }
+            Ok(Selection::Ranges { buffer_id, ranges })
+        } else {
+            Err(SFError::BufferNotFound(buffer_id))
+        }
+    }
+
+    result.vectorise(es, complement_rank0, complement_rank1)
+}
+
+pub fn conditional_transform(
+    _: &EditorState,
+    mut result: Selection,
+    arg: &SFArguments,
+) -> SFResult {
+    if !result.is_empty() {
+        Ok(match arg {
+            // TODO: think about this niladic case?
+            SFArguments::Niladic { .. } => Selection::empty(),
+            SFArguments::Monadic { es: _, left } => left.clone(),
+            SFArguments::Dyadic {
+                es: _,
+                left,
+                right: _,
+            } => left.clone(),
+        })
+    } else {
+        Ok(result)
+    }
+}