300826

src/engineering.rs

@@ -389,6 +389,26 @@ impl Engineering {
         self.sync_expr();
     }
 
+    /// Insert `× 10 ^` for scientific-notation entry: `1.5 [×10ˣ] 3 = 1500`.
+    /// Exponent may be negated with ± before `=` (`10 ^ −3` parses correctly).
+    pub fn mul_pow10(&mut self) {
+        if self.error.is_some() {
+            return;
+        }
+        if self.done {
+            // Continue from the result: 1500 [×10ˣ] 2 = 150000.
+            self.formula.clear();
+            self.done = false;
+            self.typing = true;
+        }
+        self.flush_entry();
+        self.formula.push_str(" × 10 ^ ");
+        self.entry = "0".into();
+        self.typing = false;
+        self.second = false;
+        self.sync_expr();
+    }
+
     pub fn equals(&mut self) {
         if self.error.is_some() {
             return;
@@ -884,6 +904,47 @@ mod tests {
         assert_eq!(e.display(), "1024");
     }
 
+    #[test]
+    fn mul_pow10_basic() {
+        // 1.5 ×10ˣ 3 = 1500 (× 10 ^ с приоритетом ^ над ×).
+        let mut e = Engineering::new();
+        e.input_digit('1');
+        e.input_dot();
+        e.input_digit('5');
+        e.mul_pow10();
+        e.input_digit('3');
+        e.equals();
+        assert_eq!(e.display(), "1500");
+    }
+
+    #[test]
+    fn mul_pow10_negative_exponent() {
+        // 2.5 ×10ˣ ±2 = 0.025.
+        let mut e = Engineering::new();
+        e.input_digit('2');
+        e.input_dot();
+        e.input_digit('5');
+        e.mul_pow10();
+        e.input_digit('2');
+        e.negate();
+        e.equals();
+        assert_eq!(e.display(), "0.025");
+    }
+
+    #[test]
+    fn mul_pow10_continues_result() {
+        // 2 × 3 = 6, затем 6 ×10ˣ 2 = 600.
+        let mut e = Engineering::new();
+        e.input_digit('2');
+        e.set_op("×");
+        e.input_digit('3');
+        e.equals();
+        e.mul_pow10();
+        e.input_digit('2');
+        e.equals();
+        assert_eq!(e.display(), "600");
+    }
+
     #[test]
     fn ten_pow_negative_not_zero() {
         // 10 ^ −50 ≈ 1e-50 was snapped to "0" by format_num.

src/main.rs

@@ -532,6 +532,7 @@ fn handle_engineering(calc: &mut Engineering, id: &str) {
         "eng:fact" => calc.insert_func("fact"),
         "eng:exp" => calc.insert_func("exp"),
         "eng:tenpow" => calc.insert_func("tenpow"),
+        "eng:mul10pow" => calc.mul_pow10(),
         "eng:log" => calc.insert_func("log"),
         "eng:ln" => calc.insert_func("ln"),
         "MC" => calc.memory_clear(),