🙃

src/cell.rs

@@ -4,13 +4,13 @@ use crate::evaluator::*;
 
 #[derive(Clone)]
 pub struct Cell {
-    eval: Option<Eval>,
+    eval: Eval,
     raw: String,
     deps: HashSet<CellRef>,
 }
 
 impl Cell {
-    pub fn new(eval: Option<Eval>, raw: String) -> Self {
+    pub fn new(eval: Eval, raw: String) -> Self {
         Self {
             eval,
             raw,
@@ -22,9 +22,21 @@ impl Cell {
         self.raw.clone()
     }
 
-    pub fn eval(&self) -> Option<Eval> {
+    pub fn eval(&self) -> Eval {
         self.eval.clone()
     }
+
+    pub fn add_dep(&mut self, dep: CellRef) {
+        self.deps.insert(dep);
+    }
+
+    pub fn clear_deps(&mut self) {
+        self.deps.clear();
+    }
+
+    pub fn set_eval(&mut self, eval: Eval) {
+        self.eval = eval;
+    }
 }
 
 #[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]

src/evaluator.rs

@@ -7,14 +7,12 @@ use std::fmt;
 #[derive(Debug, PartialEq, Clone)]
 pub enum Eval {
     Literal(Literal),
-    Expr(Expr),
 }
 
 impl fmt::Display for Eval {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Eval::Literal(lit) => write!(f, "{lit:?}"),
-            Eval::Expr(expr) => write!(f, "({expr})"),
         }
     }
 }
@@ -35,20 +33,26 @@ impl Evaluator {
             return Ok(());
         }
 
-        let mut eval: Option<Eval> = None;
+        let eval: Eval;
+
         if let Some(c) = raw_val.chars().nth(0)
             && c == '='
         {
-            if let Ok(e) = self.evaluate(raw_val[1..].to_owned()) {
-                eval = Some(e);
-            };
+            eval = self.evaluate(raw_val[1..].to_owned())?;
+        } else {
+            match self.evaluate(raw_val.to_owned()) {
+                Ok(e) => {
+                    eval = e;
+                }
+                Err(_) => eval = Eval::Literal(Literal::String(raw_val.to_owned())),
+            }
         }
 
         self.cells.insert(cell_ref, Cell::new(eval, raw_val));
         Ok(())
     }
 
-    pub fn get_cell(&mut self, cell_ref: CellRef) -> Result<(String, Option<Eval>), String> {
+    pub fn get_cell(&mut self, cell_ref: CellRef) -> Result<(String, Eval), String> {
         if !self.cells.contains_key(&cell_ref) {
             return Err(format!("Cell at {:?} not found.", cell_ref));
         }
@@ -58,14 +62,16 @@ impl Evaluator {
         Ok((cell.raw(), cell.eval()))
     }
 
-    pub fn evaluate(&self, str: String) -> Result<Eval, String> {
-        let mut expr = parse(&str)?;
+    pub fn evaluate(&mut self, str: String) -> Result<Eval, String> {
+        let (mut expr, mut deps) = parse(&str)?;
+
         self.evaluate_expr(&mut expr)
     }
 
-    fn evaluate_expr(&self, expr: &mut Expr) -> Result<Eval, String> {
+    fn evaluate_expr(&mut self, expr: &mut Expr) -> Result<Eval, String> {
         let res = match expr {
             Expr::Literal(lit) => Eval::Literal(lit.clone()),
+            Expr::CellRef(re) => self.get_cell(re.to_owned())?.1,
             Expr::Infix { op, lhs, rhs } => {
                 let lval = self.evaluate_expr(lhs)?;
                 let rval = self.evaluate_expr(rhs)?;
@@ -101,7 +107,6 @@ fn eval_add(lval: &Eval, rval: &Eval) -> Result<Eval, String> {
 
             Err("Evaluation error: expected string or numeric types for ADD function.".to_string())
         }
-        _ => return Err("Evalutation error: expected literals for ADD function.".to_string()),
     }
 }
 
@@ -114,7 +119,6 @@ fn eval_sub(lval: &Eval, rval: &Eval) -> Result<Eval, String> {
 
             Err("Evaluation error: expected string or numeric types for SUB function.".to_string())
         }
-        _ => return Err("Evalutation error: expected literals for SUB function.".to_string()),
     }
 }
 fn eval_mul(lval: &Eval, rval: &Eval) -> Result<Eval, String> {
@@ -126,7 +130,6 @@ fn eval_mul(lval: &Eval, rval: &Eval) -> Result<Eval, String> {
 
             Err("Evaluation error: expected string or numeric types for MUL function.".to_string())
         }
-        _ => return Err("Evalutation error: expected literals for MUL function.".to_string()),
     }
 }
 fn eval_div(lval: &Eval, rval: &Eval) -> Result<Eval, String> {
@@ -138,7 +141,6 @@ fn eval_div(lval: &Eval, rval: &Eval) -> Result<Eval, String> {
 
             Err("Evaluation error: expected string or numeric types for DIV function.".to_string())
         }
-        _ => return Err("Evalutation error: expected literals for DIV function.".to_string()),
     }
 }
 

src/parser.rs

@@ -1,5 +1,5 @@
 use crate::{cell::CellRef, tokenizer::*};
-use std::fmt;
+use std::{collections::HashSet, fmt};
 
 #[derive(Debug, PartialEq, Clone)]
 pub enum PrefixOp {
@@ -154,19 +154,24 @@ impl Expr {
     }
 }
 
-pub fn parse(input: &str) -> Result<Expr, String> {
+pub fn parse(input: &str) -> Result<(Expr, HashSet<CellRef>), String> {
     let mut tokenizer = Tokenizer::new(input)?;
     // println!("{:?}", tokenizer.tokens);
-    _parse(&mut tokenizer, 0)
+    let mut deps = HashSet::new();
+    Ok((_parse(&mut tokenizer, 0, &mut deps)?, deps))
 }
 
-pub fn _parse(input: &mut Tokenizer, min_prec: u8) -> Result<Expr, String> {
+pub fn _parse(
+    input: &mut Tokenizer,
+    min_prec: u8,
+    deps: &mut HashSet<CellRef>,
+) -> Result<Expr, String> {
     let mut lhs = match input.next() {
         Token::Literal(it) => Expr::Literal(it),
         Token::Identifier(id) if id == "true" => Expr::Literal(Literal::Boolean(true)),
         Token::Identifier(id) if id == "false" => Expr::Literal(Literal::Boolean(false)),
         Token::Paren('(') => {
-            let lhs = _parse(input, 0)?;
+            let lhs = _parse(input, 0, deps)?;
             if input.next() != Token::Paren(')') {
                 return Err(format!("Parse error: expected closing paren."));
             }
@@ -180,7 +185,7 @@ pub fn _parse(input: &mut Tokenizer, min_prec: u8) -> Result<Expr, String> {
                 it => return Err(format!("Parse error: unknown prefix operator {:?}.", it)),
             };
 
-            let rhs = _parse(input, prefix_op.prec().1)?;
+            let rhs = _parse(input, prefix_op.prec().1, deps)?;
 
             Expr::Prefix {
                 op: prefix_op,
@@ -209,7 +214,7 @@ pub fn _parse(input: &mut Tokenizer, min_prec: u8) -> Result<Expr, String> {
                         input.next(); // Skip comma
                     }
 
-                    let arg = _parse(input, 0)?;
+                    let arg = _parse(input, 0, deps)?;
                     args.push(arg);
                 }
 
@@ -218,7 +223,11 @@ pub fn _parse(input: &mut Tokenizer, min_prec: u8) -> Result<Expr, String> {
                     args: args,
                 }
             }
-            _ => Expr::CellRef(CellRef::new(id)?),
+            _ => {
+                let cell_ref = CellRef::new(id)?;
+                deps.insert(cell_ref);
+                Expr::CellRef(cell_ref)
+            }
         },
 
         it => return Err(format!("Parse error: did not expect token {:?}.", it)),
@@ -246,7 +255,7 @@ pub fn _parse(input: &mut Tokenizer, min_prec: u8) -> Result<Expr, String> {
             }
 
             input.next();
-            let rhs = _parse(input, r_prec)?;
+            let rhs = _parse(input, r_prec, deps)?;
             lhs = Expr::Infix {
                 op: infix_op,
                 lhs: Box::new(lhs),