Length by empty square braces

Reviewed-on: https://git.ablecorp.us:443/AbleScript/able-script/pulls/2

ablescript/src/ast.rs

@@ -190,6 +190,7 @@ pub enum ExprKind {
         expr: Box<Expr>,
         index: Box<Expr>,
     },
+    Len(Box<Expr>),
     Variable(String),
 }
 

ablescript/src/interpret.rs

@@ -175,6 +175,7 @@ impl ExecEnv {
                     .map(|x| x.borrow().clone())
                     .unwrap_or(Value::Nul)
             }
+            Len(expr) => Value::Int(self.eval_expr(expr)?.len()),
 
             // TODO: not too happy with constructing an artificial
             // Ident here.

ablescript/src/parser.rs

@@ -195,10 +195,7 @@ impl<'source> Parser<'source> {
 
             Token::LeftBracket => match buf.take() {
                 Some(buf) => Ok(Expr::new(
-                    ExprKind::Index {
-                        expr: Box::new(buf),
-                        index: Box::new(self.expr_flow(Token::RightBracket)?),
-                    },
+                    self.index_flow(buf)?,
                     start..self.lexer.span().end,
                 )),
                 None => Ok(Expr::new(self.cart_flow()?, start..self.lexer.span().end)),
@@ -279,6 +276,27 @@ impl<'source> Parser<'source> {
         Ok(ExprKind::Cart(cart))
     }
 
+    /// Flow for indexing operations
+    ///
+    /// Indexing with empty index resolves to length of expression, else it indexes
+    fn index_flow(&mut self, expr: Expr) -> Result<ExprKind, Error> {
+        let mut buf = None;
+        Ok(loop {
+            match self.checked_next()? {
+                Token::RightBracket => match buf {
+                    Some(index) => {
+                        break ExprKind::Index {
+                            expr: Box::new(expr),
+                            index: Box::new(index),
+                        }
+                    }
+                    None => break ExprKind::Len(Box::new(expr)),
+                },
+                token => buf = Some(self.parse_expr(token, &mut buf)?),
+            }
+        })
+    }
+
     /// Flow for operators
     ///
     /// Generates operation from LHS buffer and next expression as RHS

ablescript/src/variables.rs

@@ -122,36 +122,36 @@ impl Value {
         match self {
             Value::Abool(a) => a as _,
             Value::Bool(b) => b as _,
-            Value::Functio(func) => match func {
-                // Compares lengths of functions:
-                // BfFunctio - Sum of lengths of instructions and length of tape
-                // AbleFunctio - Sum of argument count and body length
-                // Eval - Length of input code
+            Value::Functio(f) => match f {
                 Functio::Bf {
                     instructions,
                     tape_len,
-                } => (instructions.len() + tape_len) as _,
-                Functio::Able { params, body } => (params.len() + format!("{:?}", body).len()) as _,
+                } => instructions.into_iter().map(|x| x as i32).sum::<i32>() * tape_len as i32,
+                Functio::Able { params, body } => {
+                    params
+                        .into_iter()
+                        .map(|x| x.bytes().map(|x| x as i32).sum::<i32>())
+                        .sum::<i32>()
+                        + body.len() as i32
+                }
                 Functio::Chain { functios, kind } => {
-                    let (lhs, rhs) = *functios;
-                    match kind {
-                        FunctioChainKind::Equal => {
-                            Value::Int(Value::Functio(lhs).into_i32())
-                                + Value::Int(Value::Functio(rhs).into_i32())
-                        }
-                        FunctioChainKind::ByArity => {
-                            Value::Int(Value::Functio(lhs).into_i32())
-                                * Value::Int(Value::Functio(rhs).into_i32())
+                    let (lf, rf) = *functios;
+                    Value::Functio(lf).into_i32()
+                        + Value::Functio(rf).into_i32()
+                            * match kind {
+                                FunctioChainKind::Equal => -1,
+                                FunctioChainKind::ByArity => 1,
                             }
                 }
-                    .into_i32()
-                }
-                Functio::Eval(s) => s.len() as _,
+                Functio::Eval(code) => code.bytes().map(|x| x as i32).sum(),
             },
             Value::Int(i) => i,
             Value::Nul => consts::ANSWER,
             Value::Str(text) => text.parse().unwrap_or(consts::ANSWER),
-            Value::Cart(c) => c.len() as _,
+            Value::Cart(c) => c
+                .into_iter()
+                .map(|(i, v)| i.into_i32() * v.borrow().clone().into_i32())
+                .sum(),
         }
     }
 
@@ -410,6 +410,55 @@ impl Value {
             Value::Cart(c) => c,
         }
     }
+
+    /// Get a lenght of a value
+    pub fn len(&self) -> i32 {
+        match self {
+            Value::Nul => 0,
+            Value::Str(s) => s.len() as _,
+            Value::Int(i) => i.count_zeros() as _,
+            Value::Bool(b) if *b => -2,
+            Value::Bool(_) => 2,
+            Value::Abool(a) => match a {
+                Abool::Never => -3,
+                Abool::Sometimes => {
+                    if rand::thread_rng().gen() {
+                        3
+                    } else {
+                        -3
+                    }
+                }
+                Abool::Always => 3,
+            },
+            Value::Functio(f) => match f {
+                // Compares lengths of functions:
+                // BfFunctio - Sum of lengths of instructions and length of tape
+                // AbleFunctio - Sum of argument count and body length
+                // Eval - Length of input code
+                Functio::Bf {
+                    instructions,
+                    tape_len,
+                } => (instructions.len() + tape_len) as _,
+                Functio::Able { params, body } => (params.len() + format!("{:?}", body).len()) as _,
+                Functio::Chain { functios, kind } => {
+                    let (lhs, rhs) = *functios.clone();
+                    match kind {
+                        FunctioChainKind::Equal => {
+                            Value::Int(Value::Functio(lhs).into_i32())
+                                + Value::Int(Value::Functio(rhs).into_i32())
+                        }
+                        FunctioChainKind::ByArity => {
+                            Value::Int(Value::Functio(lhs).into_i32())
+                                * Value::Int(Value::Functio(rhs).into_i32())
+                        }
+                    }
+                    .into_i32()
+                }
+                Functio::Eval(s) => s.len() as _,
+            },
+            Value::Cart(c) => c.len() as _,
+        }
+    }
 }
 
 impl ops::Add for Value {