General cleanup.

Cargo.toml

@@ -18,6 +18,7 @@ include = [
 num-traits = "*"
 
 [features]
+#default = ["no_index", "no_float", "only_i32", "no_stdlib", "unchecked"]
 default = []
 debug_msgs = []
 unchecked = []

src/builtin.rs

@@ -2,45 +2,23 @@
 //! _standard library_ of utility functions.
 
 use crate::any::Any;
-use crate::engine::Engine;
-use crate::fn_register::RegisterFn;
-use crate::parser::INT;
-
-#[cfg(not(feature = "unchecked"))]
-use crate::{parser::Position, result::EvalAltResult, RegisterResultFn};
-
 #[cfg(not(feature = "no_index"))]
 use crate::engine::Array;
-
+use crate::engine::Engine;
-#[cfg(not(feature = "no_float"))]
+use crate::fn_register::{RegisterFn, RegisterResultFn};
+use crate::parser::{Position, INT};
+use crate::result::EvalAltResult;
 use crate::FLOAT;
 
+use num_traits::{
+    identities::Zero, CheckedAdd, CheckedDiv, CheckedMul, CheckedNeg, CheckedRem, CheckedShl,
+    CheckedShr, CheckedSub,
+};
+
 use std::{
     fmt::{Debug, Display},
-    ops::{BitAnd, BitOr, BitXor, Range},
+    ops::{Add, BitAnd, BitOr, BitXor, Div, Mul, Neg, Range, Rem, Shl, Shr, Sub},
-};
+    {i32, i64, u32},
-
-#[cfg(feature = "unchecked")]
-use std::ops::{Shl, Shr};
-
-#[cfg(not(feature = "unchecked"))]
-#[cfg(not(feature = "no_float"))]
-use std::{i32, i64};
-
-#[cfg(not(feature = "unchecked"))]
-#[cfg(not(feature = "only_i32"))]
-use std::u32;
-
-#[cfg(any(feature = "unchecked", not(feature = "no_float")))]
-use std::ops::{Add, Div, Mul, Neg, Rem, Sub};
-
-#[cfg(not(feature = "unchecked"))]
-use {
-    num_traits::{
-        CheckedAdd, CheckedDiv, CheckedMul, CheckedNeg, CheckedRem, CheckedShl, CheckedShr,
-        CheckedSub,
-    },
-    std::convert::TryFrom,
 };
 
 macro_rules! reg_op {
@@ -162,12 +140,9 @@ impl Engine<'_> {
         #[cfg(not(feature = "unchecked"))]
         fn div<T>(x: T, y: T) -> Result<T, EvalAltResult>
         where
-            T: Display + CheckedDiv + PartialEq + TryFrom<i8>,
+            T: Display + CheckedDiv + PartialEq + Zero,
-        {
-            if y == <T as TryFrom<i8>>::try_from(0)
-                .map_err(|_| ())
-                .expect("zero should always succeed")
         {
+            if y == T::zero() {
                 return Err(EvalAltResult::ErrorArithmetic(
                     format!("Division by zero: {} / {}", x, y),
                     Position::none(),
@@ -191,8 +166,10 @@ impl Engine<'_> {
             })
         }
         #[cfg(not(feature = "unchecked"))]
-        fn abs<T: Display + CheckedNeg + PartialOrd + From<i8>>(x: T) -> Result<T, EvalAltResult> {
+        fn abs<T: Display + CheckedNeg + PartialOrd + Zero>(x: T) -> Result<T, EvalAltResult> {
-            if x >= 0.into() {
+            // FIX - We don't use Signed::abs() here because, contrary to documentation, it panics
+            //       when the number is ::MIN instead of returning ::MIN itself.
+            if x >= <T as Zero>::zero() {
                 Ok(x)
             } else {
                 x.checked_neg().ok_or_else(|| {
@@ -224,14 +201,15 @@ impl Engine<'_> {
             -x
         }
         #[cfg(any(feature = "unchecked", not(feature = "no_float")))]
-        fn abs_u<T: Neg + PartialOrd + From<i8>>(x: T) -> T
+        fn abs_u<T>(x: T) -> <T as Neg>::Output
         where
-            <T as Neg>::Output: Into<T>,
+            T: Neg + PartialOrd + Default + Into<<T as Neg>::Output>,
         {
-            if x < 0.into() {
+            // Numbers should default to zero
-                (-x).into()
+            if x < Default::default() {
+                -x
             } else {
-                x
+                x.into()
             }
         }
         fn lt<T: PartialOrd>(x: T, y: T) -> bool {

src/engine.rs

@@ -4,8 +4,6 @@ use crate::any::{Any, AnyExt, Dynamic, Variant};
 use crate::parser::{Expr, FnDef, Position, Stmt};
 use crate::result::EvalAltResult;
 use crate::scope::Scope;
-
-#[cfg(not(feature = "no_index"))]
 use crate::INT;
 
 use std::{
@@ -788,6 +786,9 @@ impl Engine<'_> {
                 .eval_index_expr(scope, lhs, idx_expr, *idx_pos)
                 .map(|(_, _, _, x)| x),
 
+            #[cfg(feature = "no_index")]
+            Expr::Index(_, _, _) => panic!("encountered an index expression during no_index!"),
+
             // Statement block
             Expr::Stmt(stmt, _) => self.eval_stmt(scope, stmt),
 
@@ -855,6 +856,8 @@ impl Engine<'_> {
 
                 Ok(Box::new(arr))
             }
+            #[cfg(feature = "no_index")]
+            Expr::Array(_, _) => panic!("encountered an array during no_index!"),
 
             Expr::FunctionCall(fn_name, args, def_val, pos) => {
                 let mut args = args

src/fn_register.rs

@@ -120,8 +120,9 @@ macro_rules! def_register {
                     const NUM_ARGS: usize = count_args!($($par)*);
 
                     if args.len() != NUM_ARGS {
-                        Err(EvalAltResult::ErrorFunctionArgsMismatch(fn_name.clone(), NUM_ARGS, args.len(), pos))
+                        return Err(EvalAltResult::ErrorFunctionArgsMismatch(fn_name.clone(), NUM_ARGS, args.len(), pos));
-                    } else {
+                    }
+
                     #[allow(unused_variables, unused_mut)]
                     let mut drain = args.drain(..);
                     $(
@@ -133,7 +134,6 @@ macro_rules! def_register {
                     // potentially clone the value, otherwise pass the reference.
                     let r = f($(($clone)($par)),*);
                     Ok(Box::new(r) as Dynamic)
-                    }
                 };
                 self.register_fn_raw(name, Some(vec![$(TypeId::of::<$par>()),*]), Box::new(fun));
             }
@@ -152,8 +152,9 @@ macro_rules! def_register {
                     const NUM_ARGS: usize = count_args!($($par)*);
 
                     if args.len() != NUM_ARGS {
-                        Err(EvalAltResult::ErrorFunctionArgsMismatch(fn_name.clone(), NUM_ARGS, args.len(), pos))
+                        return Err(EvalAltResult::ErrorFunctionArgsMismatch(fn_name.clone(), NUM_ARGS, args.len(), pos));
-                    } else {
+                    }
+
                     #[allow(unused_variables, unused_mut)]
                     let mut drain = args.drain(..);
                     $(
@@ -164,7 +165,6 @@ macro_rules! def_register {
                     // Call the user-supplied function using ($clone) to
                     // potentially clone the value, otherwise pass the reference.
                     Ok(f($(($clone)($par)),*))
-                    }
                 };
                 self.register_fn_raw(name, Some(vec![$(TypeId::of::<$par>()),*]), Box::new(fun));
             }
@@ -184,8 +184,9 @@ macro_rules! def_register {
                     const NUM_ARGS: usize = count_args!($($par)*);
 
                     if args.len() != NUM_ARGS {
-                        Err(EvalAltResult::ErrorFunctionArgsMismatch(fn_name.clone(), NUM_ARGS, args.len(), pos))
+                        return Err(EvalAltResult::ErrorFunctionArgsMismatch(fn_name.clone(), NUM_ARGS, args.len(), pos));
-                    } else {
+                    }
+
                     #[allow(unused_variables, unused_mut)]
                     let mut drain = args.drain(..);
                     $(
@@ -202,7 +203,6 @@ macro_rules! def_register {
                             Err(err)
                         }
                     }
-                    }
                 };
                 self.register_fn_raw(name, Some(vec![$(TypeId::of::<$par>()),*]), Box::new(fun));
             }

src/optimize.rs

@@ -141,6 +141,7 @@ fn optimize_expr(expr: Expr, changed: &mut bool) -> Expr {
             Box::new(optimize_expr(*rhs, changed)),
             pos,
         ),
+
         #[cfg(not(feature = "no_index"))]
         Expr::Index(lhs, rhs, pos) => match (*lhs, *rhs) {
             (Expr::Array(mut items, _), Expr::IntegerConstant(i, _))
@@ -158,6 +159,9 @@ fn optimize_expr(expr: Expr, changed: &mut bool) -> Expr {
                 pos,
             ),
         },
+        #[cfg(feature = "no_index")]
+        Expr::Index(_, _, _) => panic!("encountered an index expression during no_index!"),
+
         #[cfg(not(feature = "no_index"))]
         Expr::Array(items, pos) => {
             let original_len = items.len();
@@ -172,6 +176,9 @@ fn optimize_expr(expr: Expr, changed: &mut bool) -> Expr {
             Expr::Array(items, pos)
         }
 
+        #[cfg(feature = "no_index")]
+        Expr::Array(_, _) => panic!("encountered an array during no_index!"),
+
         Expr::And(lhs, rhs) => match (*lhs, *rhs) {
             (Expr::True(_), rhs) => {
                 *changed = true;
@@ -208,7 +215,6 @@ fn optimize_expr(expr: Expr, changed: &mut bool) -> Expr {
                 Box::new(optimize_expr(rhs, changed)),
             ),
         },
-
         Expr::FunctionCall(id, args, def_value, pos) => {
             let original_len = args.len();
 

src/parser.rs

@@ -3,13 +3,18 @@
 use crate::any::Dynamic;
 use crate::error::{LexError, ParseError, ParseErrorType};
 use crate::optimize::optimize;
+
 use std::{borrow::Cow, char, fmt, iter::Peekable, str::Chars, str::FromStr, usize};
 
-/// The system integer type
+/// The system integer type.
+///
+/// If the `only_i32` feature is enabled, this will be `i32` instead.
 #[cfg(not(feature = "only_i32"))]
 pub type INT = i64;
 
 /// The system integer type
+///
+/// If the `only_i32` feature is not enabled, this will be `i64` instead.
 #[cfg(feature = "only_i32")]
 pub type INT = i32;
 
@@ -179,9 +184,7 @@ pub enum Expr {
     FunctionCall(String, Vec<Expr>, Option<Dynamic>, Position),
     Assignment(Box<Expr>, Box<Expr>, Position),
     Dot(Box<Expr>, Box<Expr>, Position),
-    #[cfg(not(feature = "no_index"))]
     Index(Box<Expr>, Box<Expr>, Position),
-    #[cfg(not(feature = "no_index"))]
     Array(Vec<Expr>, Position),
     And(Box<Expr>, Box<Expr>),
     Or(Box<Expr>, Box<Expr>),
@@ -197,24 +200,21 @@ impl Expr {
             | Expr::Identifier(_, pos)
             | Expr::CharConstant(_, pos)
             | Expr::StringConstant(_, pos)
-            | Expr::FunctionCall(_, _, _, pos)
             | Expr::Stmt(_, pos)
+            | Expr::FunctionCall(_, _, _, pos)
+            | Expr::Array(_, pos)
             | Expr::True(pos)
             | Expr::False(pos)
             | Expr::Unit(pos) => *pos,
 
-            Expr::Assignment(e, _, _) | Expr::Dot(e, _, _) | Expr::And(e, _) | Expr::Or(e, _) => {
+            Expr::Assignment(e, _, _)
-                e.position()
+            | Expr::Dot(e, _, _)
-            }
+            | Expr::Index(e, _, _)
+            | Expr::And(e, _)
+            | Expr::Or(e, _) => e.position(),
 
             #[cfg(not(feature = "no_float"))]
             Expr::FloatConstant(_, pos) => *pos,
-
-            #[cfg(not(feature = "no_index"))]
-            Expr::Index(e, _, _) => e.position(),
-
-            #[cfg(not(feature = "no_index"))]
-            Expr::Array(_, pos) => *pos,
         }
     }
 

src/result.rs

@@ -3,6 +3,7 @@
 use crate::any::Dynamic;
 use crate::error::ParseError;
 use crate::parser::{Position, INT};
+
 use std::{error::Error, fmt};
 
 /// Evaluation result.
@@ -75,12 +76,12 @@ impl Error for EvalAltResult {
             Self::ErrorArrayBounds(_, index, _) if *index < 0 => {
                 "Array access expects non-negative index"
             }
-            Self::ErrorArrayBounds(max, _, _) if *max == 0 => "Access of empty array",
+            Self::ErrorArrayBounds(0, _, _) => "Access of empty array",
             Self::ErrorArrayBounds(_, _, _) => "Array index out of bounds",
             Self::ErrorStringBounds(_, index, _) if *index < 0 => {
                 "Indexing a string expects a non-negative index"
             }
-            Self::ErrorStringBounds(max, _, _) if *max == 0 => "Indexing of empty string",
+            Self::ErrorStringBounds(0, _, _) => "Indexing of empty string",
             Self::ErrorStringBounds(_, _, _) => "String index out of bounds",
             Self::ErrorIfGuard(_) => "If guard expects boolean expression",
             Self::ErrorFor(_) => "For loop expects array or range",
@@ -128,6 +129,16 @@ impl fmt::Display for EvalAltResult {
                 write!(f, "{} '{}': {}", desc, filename, err)
             }
             Self::ErrorParsing(p) => write!(f, "Syntax error: {}", p),
+            Self::ErrorFunctionArgsMismatch(fun, 0, n, pos) => write!(
+                f,
+                "Function '{}' expects no argument but {} found ({})",
+                fun, n, pos
+            ),
+            Self::ErrorFunctionArgsMismatch(fun, 1, n, pos) => write!(
+                f,
+                "Function '{}' expects one argument but {} found ({})",
+                fun, n, pos
+            ),
             Self::ErrorFunctionArgsMismatch(fun, need, n, pos) => write!(
                 f,
                 "Function '{}' expects {} argument(s) but {} found ({})",
@@ -142,26 +153,30 @@ impl fmt::Display for EvalAltResult {
             Self::ErrorArrayBounds(_, index, pos) if *index < 0 => {
                 write!(f, "{}: {} < 0 ({})", desc, index, pos)
             }
-            Self::ErrorArrayBounds(max, _, pos) if *max == 0 => write!(f, "{} ({})", desc, pos),
+            Self::ErrorArrayBounds(0, _, pos) => write!(f, "{} ({})", desc, pos),
+            Self::ErrorArrayBounds(1, index, pos) => write!(
+                f,
+                "Array index {} is out of bounds: only one element in the array ({})",
+                index, pos
+            ),
             Self::ErrorArrayBounds(max, index, pos) => write!(
                 f,
-                "Array index {} is out of bounds: only {} element{} in the array ({})",
+                "Array index {} is out of bounds: only {} elements in the array ({})",
-                index,
+                index, max, pos
-                max,
-                if *max > 1 { "s" } else { "" },
-                pos
             ),
             Self::ErrorStringBounds(_, index, pos) if *index < 0 => {
                 write!(f, "{}: {} < 0 ({})", desc, index, pos)
             }
-            Self::ErrorStringBounds(max, _, pos) if *max == 0 => write!(f, "{} ({})", desc, pos),
+            Self::ErrorStringBounds(0, _, pos) => write!(f, "{} ({})", desc, pos),
+            Self::ErrorStringBounds(1, index, pos) => write!(
+                f,
+                "String index {} is out of bounds: only one character in the string ({})",
+                index, pos
+            ),
             Self::ErrorStringBounds(max, index, pos) => write!(
                 f,
-                "String index {} is out of bounds: only {} character{} in the string ({})",
+                "String index {} is out of bounds: only {} characters in the string ({})",
-                index,
+                index, max, pos
-                max,
-                if *max > 1 { "s" } else { "" },
-                pos
             ),
         }
     }

src/scope.rs

@@ -1,6 +1,7 @@
 //! Module that defines the `Scope` type representing a function call-stack scope.
 
 use crate::any::{Any, Dynamic};
+
 use std::borrow::Cow;
 
 /// A type containing information about current scope.

tests/math.rs

@@ -24,6 +24,10 @@ fn test_math() -> Result<(), EvalAltResult> {
     {
         #[cfg(not(feature = "only_i32"))]
         {
+            match engine.eval::<INT>("(-9223372036854775808).abs()") {
+                Err(EvalAltResult::ErrorArithmetic(_, _)) => (),
+                r => panic!("should return overflow error: {:?}", r),
+            }
             match engine.eval::<INT>("9223372036854775807 + 1") {
                 Err(EvalAltResult::ErrorArithmetic(_, _)) => (),
                 r => panic!("should return overflow error: {:?}", r),