Add keep_every command

src/keep_every.rs

@@ -0,0 +1,65 @@
+use itertools::Itertools;
+use kakplugin::{get_selections_desc_unordered, set_selections_desc, KakError, SelectionDesc};
+
+#[derive(Debug, clap::Args)]
+pub struct Options {
+    #[clap(index = 1, value_parser = clap::value_parser!(u16).range(2..))]
+    keep_every: u16,
+}
+
+pub fn keep_every(options: &Options) -> Result<String, KakError> {
+    let selections_desc = get_selections_desc_unordered(None)?;
+    let old_count = selections_desc.len();
+
+    let new_selections_desc = apply(options, &selections_desc);
+
+    set_selections_desc(new_selections_desc.iter())?;
+
+    let new_count = new_selections_desc.len();
+
+    Ok(format!("{} kept from {}", new_count, old_count))
+}
+
+fn apply(options: &Options, selections_desc: &[SelectionDesc]) -> Vec<SelectionDesc> {
+    selections_desc
+        .iter()
+        .chunks(options.keep_every.into())
+        .into_iter()
+        .flat_map(|mut it| it.next())
+        .copied()
+        .collect::<Vec<_>>()
+}
+
+#[cfg(test)]
+mod tests {
+    // Selection desc creator
+    macro_rules! sd {
+        ($a:expr) => {{
+            sd!($a, $a)
+        }};
+        ($b:expr, $d:expr) => {{
+            sd!(1, $b, 1, $d)
+        }};
+        ($a:expr, $b:expr,$c:expr,$d:expr) => {{
+            SelectionDesc {
+                left: AnchorPosition { row: $a, col: $b },
+                right: AnchorPosition { row: $c, col: $d },
+            }
+        }};
+    }
+
+    use kakplugin::{AnchorPosition, SelectionDesc};
+
+    use super::*;
+    #[test]
+    fn test() {
+        assert_eq!(apply(&Options { keep_every: 2 }, &[sd!(1),]), &[sd!(1),]);
+        assert_eq!(
+            apply(
+                &Options { keep_every: 2 },
+                &[sd!(1), sd!(2), sd!(3), sd!(4), sd!(5), sd!(6), sd!(7),]
+            ),
+            &[sd!(1), sd!(3), sd!(5), sd!(7),]
+        );
+    }
+}

src/main.rs

@@ -14,6 +14,7 @@ mod errors;
 mod incr;
 mod invert;
 mod join;
+mod keep_every;
 mod math_eval;
 mod pad;
 mod rev;
@@ -75,6 +76,8 @@ enum Commands {
     Rev(rev::Options),
     #[clap(about = "Join selections")]
     Join(join::Options),
+    #[clap(about = "Keep a subset of selections", visible_aliases = &["keep"])]
+    KeepEvery(keep_every::Options),
 }
 
 fn main() {
@@ -127,5 +130,6 @@ fn run() -> Result<String, KakError> {
         Commands::Decr(o) => incr::incr(o, false),
         Commands::Rev(o) => rev::rev(o),
         Commands::Join(o) => join::join(o),
+        Commands::KeepEvery(o) => keep_every::keep_every(o),
     }
 }