build: update flake (late commit)

I think this is more readable, too

flake.lock

@@ -20,18 +20,15 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1780749050,
+        "lastModified": 1791260994,
-        "narHash": "sha256-3av0pIjlOWQ6rDbNOmpUSvbNnJkGORQKKjb4LtCZsIY=",
+        "narHash": "sha256-MFBjw66d4h06MvpW6lIl7RwarLteD0sk859CncGwb1Q=",
-        "owner": "NixOS",
+        "rev": "151fa4e8ddfdd8dd25d945ad94ed54a13de9f6e4",
-        "repo": "nixpkgs",
+        "type": "tarball",
-        "rev": "a799d3e3886da994fa307f817a6bc705ae538eeb",
+        "url": "https://releases.nixos.org/nixos/unstable/nixos-26.11pre1086391.151fa4e8ddfd/nixexprs.tar.zst?lastModified=1791260994&rev=151fa4e8ddfdd8dd25d945ad94ed54a13de9f6e4"
-        "type": "github"
       },
       "original": {
-        "owner": "NixOS",
+        "type": "tarball",
-        "ref": "nixos-unstable",
+        "url": "https://channels.nixos.org/nixos-unstable/nixexprs.tar.zst"
-        "repo": "nixpkgs",
-        "type": "github"
       }
     },
     "root": {

flake.nix

@@ -1,6 +1,6 @@
 {
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    nixpkgs.url = "https://channels.nixos.org/nixos-unstable/nixexprs.tar.zst";
 
     flake-utils.url = "github:numtide/flake-utils";
   };

src/formatting.rs

@@ -2,19 +2,20 @@ use rug::Float;
 
 use crate::nodes::{self, Error};
 
-pub fn pretty_eval(mut input: String, max_digits: usize) -> Result<String, Error> {
+pub fn pretty_eval(input: &str, max_digits: usize) -> Result<String, Error> {
-    // no need to remove the characters here,
+    let (prefix, deliminator, input) = input
-    // as we ignore the them in all other logic already
+        .rsplit_once('=')
-    let should_add_back_alignment = input.contains('&');
+        .map(|(p, i)| (p, "= ", i))
-    let should_add_back_backslash = input.contains('\\');
+        .unwrap_or_else(|| {
-    let leading_spaces = input.chars().take_while(|c| *c == ' ').count();
+            input
+                .rsplit_once('&')
+                .map(|(p, i)| (p, "& ", i))
+                .unwrap_or(("", "", input))
+        });
 
-    let should_add_back_equals = input
+    // no need to remove the character here,
-        .find('=')
+    // as we ignore it in all other logic already
-        .inspect(|i| {
+    let should_add_back_backslash = input.contains('\\');
-            input.remove(*i);
-        })
-        .is_some();
 
     let result = nodes::eval(&input)?;
     let display_digits =
@@ -32,38 +33,11 @@ pub fn pretty_eval(mut input: String, max_digits: usize) -> Result<String, Error
             });
 
     Ok(format!(
-        "{}{}{result:.display_digits$}{}",
+        "{prefix}{deliminator}{result:.display_digits$}{}",
-        " ".repeat(leading_spaces),
-        if should_add_back_equals && should_add_back_alignment {
-            "& = "
-        } else if should_add_back_equals {
-            "= "
-        } else if should_add_back_alignment {
-            "& "
-        } else {
-            ""
-        },
         if should_add_back_backslash { " \\" } else { "" }
     )
     .replace('e', " * 10^"))
 }
-#[test]
-fn test_character_readdition() {
-    assert_eq!(pretty_eval(" = 11".into(), 10).unwrap(), " = 11");
-    assert_eq!(pretty_eval(" &= 11".into(), 10).unwrap(), " & = 11");
-    assert_eq!(pretty_eval(" & 11".into(), 10).unwrap(), " & 11");
-    assert_eq!(pretty_eval(" & 11 \\".into(), 10).unwrap(), " & 11 \\");
-}
-#[test]
-fn test_basic_up_to_999() {
-    assert_eq!(pretty_eval("1".into(), 10).unwrap(), "1");
-    assert_eq!(pretty_eval("10".into(), 10).unwrap(), "10");
-    assert_eq!(pretty_eval("100".into(), 10).unwrap(), "100");
-    assert_eq!(pretty_eval("999".into(), 10).unwrap(), "999");
-    assert_eq!(pretty_eval("1000".into(), 10).unwrap(), "1 * 10^3");
-
-    assert_eq!(pretty_eval("11.111111".into(), 10).unwrap(), "11.111111");
-}
 
 pub fn get_significant_digits(n: &Float) -> usize {
     let raw_string = n.to_string().replace('.', "");
@@ -99,12 +73,33 @@ pub fn get_significant_digits(n: &Float) -> usize {
 }
 
 #[cfg(test)]
+mod tests {
+    use super::*;
     fn eval(s: &str) -> Float {
         crate::nodes::eval(s).unwrap()
     }
 
     #[test]
-fn test_get_significant_digits() {
+    fn character_readdition() {
+        assert_eq!(pretty_eval(" = 11", 10).unwrap(), " = 11");
+        assert_eq!(pretty_eval(" &= 11", 10).unwrap(), " &= 11");
+        assert_eq!(pretty_eval(" & 11", 10).unwrap(), " & 11");
+        assert_eq!(pretty_eval(" & 11 \\", 10).unwrap(), " & 11 \\");
+    }
+
+    #[test]
+    fn basic_output_up_to_999() {
+        assert_eq!(pretty_eval("1", 10).unwrap(), "1");
+        assert_eq!(pretty_eval("10", 10).unwrap(), "10");
+        assert_eq!(pretty_eval("100", 10).unwrap(), "100");
+        assert_eq!(pretty_eval("999", 10).unwrap(), "999");
+        assert_eq!(pretty_eval("1000", 10).unwrap(), "1 * 10^3");
+
+        assert_eq!(pretty_eval("11.111111", 10).unwrap(), "11.111111");
+    }
+
+    #[test]
+    fn basic_get_significant_digits() {
         let many_zeros = eval("14.00643 + 1.00784 * 4 + 35.446 + 15.9994 * 4");
         assert_eq!(many_zeros.to_f64(), 117.48139);
         let many_nines = eval("12.0096 + 15.9994 * 2");
@@ -119,3 +114,4 @@ fn test_get_significant_digits() {
         assert_eq!(get_significant_digits(&zero_nine_zero), 6);
         assert_eq!(get_significant_digits(&test_4), 7);
     }
+}

src/main.rs

@@ -17,7 +17,7 @@ fn main() -> ExitCode {
             buf
         });
 
-    match lib::formatting::pretty_eval(input, 10) {
+    match lib::formatting::pretty_eval(&input, 10) {
         Ok(s) => println!("{s}"),
 
         Err(e) => {