Brought code up to point where it can run and fill in and print a grid.

src/main.rs

@@ -1,4 +1,12 @@
-use std::borrow::BorrowMut;
+use std::rc::Rc;
+use std::cell::RefCell;
+
+struct Grid {
+
+    rows: Vec<Vec<Rc<RefCell<CellValue>>>>, // Read from top to bottom
+    columns: Vec<Vec<Rc<RefCell<CellValue>>>>,
+    sections: Vec<Vec<Rc<RefCell<CellValue>>>>
+}
 
 enum CellValue {
     FIXED(u8),
@@ -6,33 +14,28 @@ enum CellValue {
     UNKNOWN(Vec<u8>)
 }
 
-struct Cell(CellValue);
+impl Grid {
-
+    fn get(&self, r: usize, c: usize) -> Result<Rc<RefCell<CellValue>>, &str> {
-struct Grid<'a> {
+        if (r > 9) | (c > 9) {
-    rows: Vec<[&'a mut Cell; 9]>, // Read from top to bottom
+            return Err("Row or column indices are out of bounds");
-    columns: Vec<[&'a Cell; 9]>, // Left to right
-    sections: Vec<[&'a Cell; 9]> // left to right, top to bottom
-}
-
-impl<'a> Grid<'a> {
-    fn get(&self, r: usize, c: usize) -> Option<&Cell> {
-        let row = self.rows.get(r)?;
-        let cell = &row[c];
-
-        return Some(&cell);
         }
 
-    fn get_mut(&'a mut self, r: usize, c: usize) -> Option<&'a mut Cell> {
+        let row = match self.rows.get(r) {
-        let row : &'a mut [&'a mut Cell; 9] = self.rows.get_mut(r)?;
+            Some(x) => x,
-        let cell : &'a mut Cell = row[c].borrow_mut();
+            None => {return Err("Row index is out of bounds")}
+        };
 
-        return Some(cell);
+        let cell = match row.get(c) {
+            Some(x) => x,
+            None => {return Err("Column index is out of bounds")}
+        };
 
+        return Ok(Rc::clone(cell));
     }
 
     fn print(&self) {
         for r in 0..9 {
-            if (r & 3 == 0) && (r > 0) {
+            if (r % 3 == 0) && (r > 0) {
                 println!("---+---+---");
             }
 
@@ -41,65 +44,55 @@ impl<'a> Grid<'a> {
                     print!("|");
                 }
 
-                let value = &self.get(r, c).unwrap().0;
+                let value = self.get(r, c).unwrap_or_else(|err| panic!());
-                match value {
+                match *value.borrow() {
                     CellValue::FIXED(x) => print!("{}", x),
                     _ => print!(" ")
                 };
-
             }
 
             print!("\n");
         }
     }
-}
-
-fn main() {
-    println!("Hello, world!");
-    let grid = retrieve_grid();
-    grid.print();
-
-}
-
-fn empty_grid<'a>() -> Grid<'a> {
-    let mut placeholder_cell : Cell = Cell(CellValue::FIXED(0));
 
+    fn new() -> Grid {
         // Rows first; we need to create cells for all of them
-    let mut rows : Vec<[&'a mut Cell; 9]> = Vec::new();
+        let mut rows: Vec<Vec<Rc<RefCell<CellValue>>>> = Vec::new();
         for _r in 0..9 {
-        let mut new_row : [&'a mut Cell; 9] = [&mut placeholder_cell; 9];
+            let mut new_row: Vec<Rc<RefCell<CellValue>>> = Vec::new();
-        for i in 0..9{
-            new_row[i] = &mut initial_empty_cell();
-        }
 
+            for _i in 0..9 {
+                let empty_cell = initial_empty_cell();
+                new_row.push(Rc::new(empty_cell));
+
+            }
             rows.push(new_row);
         }
 
             // Columns next; now we have to retrieve the cells from the different rows
-    let mut columns : Vec<[&'a Cell; 9]> = Vec::new();
+            let mut columns : Vec<Vec<Rc<RefCell<CellValue>>>> = Vec::new();
             for c in 0..9 {
-        let mut new_column : [&'a Cell; 9] = [&placeholder_cell; 9];
+                let mut new_column : Vec<Rc<RefCell<CellValue>>> = Vec::new();
                 for r in 0..9{
-            new_column[r] = rows.get(r).unwrap()[c]; // TODO - improve performance by using get_unchecked
+                    new_column.push(Rc::clone(&rows.get(r).unwrap()[c]));
                 }
                 columns.push(new_column);
             }
 
             // Sections next; now we have to retrieve the cells from different rows and columns
             // We read sections from left to right, top to bottom
-    let mut sections : Vec<[&'a Cell; 9]> = Vec::new();
+            let mut sections : Vec<Vec<Rc<RefCell<CellValue>>>> = Vec::new();
             for r in 0..3 {
                 for c in 0..3 {
-            let mut new_section : [&'a Cell; 9] = [&placeholder_cell; 9];
+                    let mut new_section : Vec<Rc<RefCell<CellValue>>> = Vec::new();
 
                     for internal_r in 0..3 {
                         let global_r = 3*r + internal_r;
 
                         for internal_c in 0..3 {
                             let global_c = 3*c + internal_c;
-                    let index = 3*internal_c + internal_r;
 
-                    new_section[index] = rows.get(global_r).unwrap()[global_c];
+                            new_section.push(Rc::clone(&rows.get(global_r).unwrap()[global_c]));
                         }
                     }
 
@@ -108,18 +101,67 @@ fn empty_grid<'a>() -> Grid<'a> {
                 }
             }
 
-    return Grid {rows, columns, sections};
+        return Grid { rows, columns, sections };
+    }
 }
 
-fn initial_empty_cell() -> Cell {
+fn initial_empty_cell() -> RefCell<CellValue> {
-    return Cell(CellValue::UNKNOWN(vec![1, 2, 3, 4, 5, 6, 7, 8, 9]));
+    return RefCell::new(CellValue::UNKNOWN(vec![1, 2, 3, 4, 5, 6, 7, 8, 9]));
 }
 
+
+fn main() {
+    println!("Hello, world!");
+    let grid = retrieve_grid();
+    grid.print();
+
+}
+
+
+
+
 /**
     For now this is a stub with a pre-programmed grid; later I'll add functionality to read a CSV file
  */
-fn retrieve_grid<'a>() -> Grid<'a> {
+fn retrieve_grid() -> Grid {
-    let mut grid = empty_grid();
+    let grid = Grid::new();
+    
+
+    grid.get(0, 4).unwrap().replace(CellValue::FIXED(8));
+    grid.get(0, 5).unwrap().replace(CellValue::FIXED(5));
+    grid.get(0, 6).unwrap().replace(CellValue::FIXED(6));
+
+    grid.get(2, 3).unwrap().replace(CellValue::FIXED(9));
+    grid.get(2, 4).unwrap().replace(CellValue::FIXED(4));
+    grid.get(2, 5).unwrap().replace(CellValue::FIXED(3));
+    grid.get(2, 6).unwrap().replace(CellValue::FIXED(5));
+    grid.get(2, 7).unwrap().replace(CellValue::FIXED(7));
+
+    grid.get(3, 0).unwrap().replace(CellValue::FIXED(8));
+    grid.get(3, 2).unwrap().replace(CellValue::FIXED(2));
+    grid.get(3, 3).unwrap().replace(CellValue::FIXED(6));
+    grid.get(3, 4).unwrap().replace(CellValue::FIXED(7));
+    grid.get(3, 5).unwrap().replace(CellValue::FIXED(4));
+    grid.get(3, 6).unwrap().replace(CellValue::FIXED(9));
+
+    grid.get(4, 4).unwrap().replace(CellValue::FIXED(9));
+    grid.get(4, 8).unwrap().replace(CellValue::FIXED(5));
+
+    grid.get(5, 1).unwrap().replace(CellValue::FIXED(6));
+    grid.get(5, 6).unwrap().replace(CellValue::FIXED(2));
+
+    grid.get(6, 1).unwrap().replace(CellValue::FIXED(8));
+    grid.get(6, 8).unwrap().replace(CellValue::FIXED(2));
+
+    grid.get(7, 3).unwrap().replace(CellValue::FIXED(7));
+    grid.get(7, 5).unwrap().replace(CellValue::FIXED(6));
+    grid.get(7, 7).unwrap().replace(CellValue::FIXED(5));
+    grid.get(7, 8).unwrap().replace(CellValue::FIXED(4));
+
+    grid.get(8, 2).unwrap().replace(CellValue::FIXED(7));
+    grid.get(8, 3).unwrap().replace(CellValue::FIXED(4));
+    
+    /*
     
     grid.get_mut(0, 4).unwrap().0 = CellValue::FIXED(8);
     grid.get_mut(0, 5).unwrap().0 = CellValue::FIXED(5);
@@ -155,6 +197,8 @@ fn retrieve_grid<'a>() -> Grid<'a> {
     grid.get_mut(8, 2).unwrap().0 = CellValue::FIXED(7);
     grid.get_mut(8, 3).unwrap().0 = CellValue::FIXED(4);
     
+     */
+
 
     return grid;
 }