display single segment prompt

src/display.rs

@@ -227,21 +227,7 @@ impl DispalyState {
         self.0 = seg;
     }
 
-    pub fn prompt(&mut self) {
+    pub fn empty(&mut self) {
-        self.set([
-            SegmentState::Prompt(false),
-            SegmentState::Prompt(true),
-            SegmentState::Prompt(false),
-            SegmentState::Prompt(false),
-            SegmentState::Prompt(false),
-            SegmentState::Prompt(false),
-            SegmentState::Prompt(false),
-            SegmentState::Prompt(false),
-            SegmentState::Prompt(false),
-        ])
-    }
-
-    pub fn error(&mut self) {
         self.set([
             SegmentState::Off,
             SegmentState::Dot,
@@ -254,6 +240,28 @@ impl DispalyState {
             SegmentState::Off,
         ])
     }
+
+    pub fn prompt(&mut self, segment: usize) {
+        self[segment] = if segment == 1 {
+            SegmentState::Prompt(true)
+        } else {
+            SegmentState::Prompt(false)
+        };
+    }
+
+    pub fn error(&mut self) {
+        self.set([
+            SegmentState::Minus,
+            SegmentState::Minus,
+            SegmentState::Minus,
+            SegmentState::Minus,
+            SegmentState::Minus,
+            SegmentState::Minus,
+            SegmentState::Minus,
+            SegmentState::Minus,
+            SegmentState::Minus,
+        ])
+    }
 }
 
 // Show data on segment display

src/main.rs

@@ -190,7 +190,12 @@ impl NumberInput {
 
 impl Show for NumberInput {
     fn show(&self, display: &mut DispalyState) {
-        display.prompt();
+        display.empty();
+        if !self.enter_exponent && self.significant_pos < DISPLAY_SEGMENTS_SIG {
+            display.prompt(self.significant_pos + 1);
+        } else if self.enter_exponent && self.exponent_pos < DISPLAY_SEGMENTS_EXP {
+            display.prompt(DISPLAY_SEGMENTS_SIG + 2 + self.exponent_pos);
+        }
         display[DISPLAY_SEGMENT_SIG_MINUS] = if self.minus {
             SegmentState::Minus
         } else {