1 files changed, 52 insertions, 12 deletions

diff --git a/rprt-engine/src/selection_functions/function_character.rs b/rprt-engine/src/selection_functions/function_character.rs
index 3d9695f..0d0699f 100644
--- a/rprt-engine/src/selection_functions/function_character.rs
+++ b/rprt-engine/src/selection_functions/function_character.rs
@@ -4,7 +4,7 @@ use crate::selection_functions::types::{get_buffer, SFArguments, SFError, SFResu
 use crate::state::EditorState;
 
 selection_function_param! {
-    name: character_structural,
+    name: character,
     param_type: usize,
     niladic: |(param, es): (usize, &EditorState)| {
         let buf = get_buffer(es, es.current_buffer_id)?;
@@ -14,19 +14,15 @@ selection_function_param! {
 
         }) },
     monadic_rank0: |_, buffer_id, pos| Ok(Selection::Position {buffer_id, pos}),
-    monadic_rank1: |(param, _), buffer_id, int| Ok(Selection::Position {buffer_id, pos: usize::min(int.end, *param)})
+    monadic_rank1: |(param, _), buffer_id, int| Ok(
+        Selection::Position {buffer_id, pos: usize::min(int.end, *param)}
+    )
 }
 
-selection_function_param! {
-    name: character_sequential,
+selection_function_param!(
+    name: sequential_character,
     param_type: usize,
-    niladic: |(param, es): (usize, &EditorState)| {
-        let buf = get_buffer(es, es.current_buffer_id)?;
-        Ok(Selection::Position {
-            buffer_id: es.current_buffer_id,
-            pos: usize::min(param, buf.max_pos()),
-        })
-    },
+    niladic: |_| Err(SFError::NoNiladicForm(";n").into()),
     monadic_rank0: |(param, es), buffer_id, pos| {
         let buf = get_buffer(es, buffer_id)?;
         Ok(Selection::Position {buffer_id, pos: usize::min(pos+*param, buf.max_pos())})
@@ -35,4 +31,48 @@ selection_function_param! {
         let buf = get_buffer(es, buffer_id)?;
         Ok(Selection::Position {buffer_id, pos: usize::min(int.end+*param, buf.max_pos())})
     }
-}
+);
+
+selection_function_param!(
+    name: reverse_character,
+    param_type: usize,
+    niladic: |(param, es): (usize, &EditorState)| {
+        let buf = get_buffer(es, es.current_buffer_id)?;
+        Ok(Selection::Position {
+            buffer_id: es.current_buffer_id,
+            pos: if buf.max_pos() < param {
+                0
+            } else {
+                buf.max_pos() - param
+            },
+        })
+    },
+    monadic_rank0: |_, buffer_id, pos| Ok(Selection::Position {buffer_id, pos}),
+    monadic_rank1: |(param, _), buffer_id, int| Ok(
+        Selection::Position {buffer_id, pos: usize::min(int.end, *param)}
+    )
+);
+
+selection_function_param!(
+    name: sequential_reverse_character,
+    param_type: usize,
+    niladic: |_| Err(SFError::NoNiladicForm(";'n").into()),
+    monadic_rank0: |(param, _), buffer_id, pos| {
+        Ok(Selection::Position {buffer_id, pos: if *param<pos {pos - *param} else {0}})
+    },
+    monadic_rank1: |(param, _), buffer_id, int| {
+        Ok(Selection::Position {buffer_id, pos: if *param<int.end {int.end - *param} else {0}})
+    }
+);
+
+selection_function_param!(
+    name: reverse_sequential_character,
+    param_type: usize,
+    niladic: |_| Err(SFError::NoNiladicForm("';n").into()),
+    monadic_rank0: |(param, _), buffer_id, pos| {
+        Ok(Selection::Position {buffer_id, pos: if *param<pos {pos - *param} else {0}})
+    },
+    monadic_rank1: |(param, _), buffer_id, int| {
+        Ok(Selection::Position {buffer_id, pos: if *param<int.start {int.start - *param} else {0}})
+    }
+);