Allow calculator to be customized as a parameter

src/math_eval.rs

@@ -3,13 +3,25 @@ use kakplugin::{get_selections, set_selections, KakError};
 use std::borrow::Cow;
 
 #[derive(clap::Args, Debug)]
-pub struct Options;
-pub fn math_eval(_options: &Options) -> Result<String, KakError> {
+pub struct Options {
+    /// Additional arguments to pass to the math evaluator
+    ///
+    /// For example, you can run `kakutils-rs bc + 5` to add 5 to all selections
+    extra_math_args: Option<Vec<String>>,
+}
+pub fn math_eval(options: &Options) -> Result<String, KakError> {
     let mut err_count: usize = 0;
 
     let selections = get_selections(None)?;
 
-    set_selections(selections.iter().map(|s| match eval(s) {
+    let extra = options.extra_math_args.as_ref().map(|v| v.join(" "));
+
+    set_selections(selections.iter().map(|s| {
+        match eval(&if let Some(e) = &extra {
+            Cow::Owned(format!("{s} {e}"))
+        } else {
+            Cow::Borrowed(s)
+        }) {
             Ok(Value::Float(f)) => Cow::Owned(f.to_string()),
             Ok(Value::Int(f)) => Cow::Owned(f.to_string()),
             Ok(_) => Cow::Borrowed(""),
@@ -19,6 +31,7 @@ pub fn math_eval(_options: &Options) -> Result<String, KakError> {
                 // Set the selection to empty
                 Cow::Borrowed("")
             }
+        }
     }))?;
 
     Ok(if err_count == 0 {