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0f46bc7725
rhai/src/engine.rs
Stephen Chung dba4510456 Better function parameter names.
2021-08-13 13:42:39 +08:00

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//! Main module defining the script evaluation [`Engine`].
use crate::ast::{Expr, FnCallExpr, Ident, OpAssignment, ReturnType, Stmt, AST_OPTION_FLAGS::*};
use crate::custom_syntax::CustomSyntax;
use crate::dynamic::{map_std_type_name, AccessMode, Union, Variant};
use crate::fn_hash::get_hasher;
use crate::fn_native::{
CallableFunction, IteratorFn, OnDebugCallback, OnPrintCallback, OnVarCallback,
};
use crate::module::NamespaceRef;
use crate::optimize::OptimizationLevel;
use crate::packages::{Package, StandardPackage};
use crate::r#unsafe::unsafe_cast_var_name_to_lifetime;
use crate::token::Token;
use crate::{
Dynamic, EvalAltResult, Identifier, ImmutableString, Module, Position, RhaiResult, Scope,
Shared, StaticVec, INT,
};
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
use std::{
any::{type_name, TypeId},
borrow::Cow,
collections::{BTreeMap, BTreeSet},
fmt,
hash::{Hash, Hasher},
iter::{FromIterator, Rev, Zip},
num::{NonZeroU8, NonZeroUsize},
ops::{Deref, DerefMut},
};
#[cfg(not(feature = "no_index"))]
use crate::Array;
#[cfg(not(feature = "no_object"))]
use crate::Map;
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
use crate::ast::FnCallHashes;
pub type Precedence = NonZeroU8;
/// _(internals)_ A stack of imported [modules][Module].
/// Exported under the `internals` feature only.
///
/// # Volatile Data Structure
///
/// This type is volatile and may change.
//
// # Implementation Notes
//
// We cannot use Cow<str> here because `eval` may load a [module][Module] and
// the module name will live beyond the AST of the eval script text.
// The best we can do is a shared reference.
//
// This implementation splits the module names from the shared modules to improve data locality.
// Most usage will be looking up a particular key from the list and then getting the module that
// corresponds to that key.
#[derive(Clone, Default)]
pub struct Imports {
keys: StaticVec<Identifier>,
modules: StaticVec<Shared<Module>>,
}
impl Imports {
/// Create a new stack of imported [modules][Module].
#[inline(always)]
#[must_use]
pub fn new() -> Self {
Self {
keys: StaticVec::new(),
modules: StaticVec::new(),
}
}
/// Get the length of this stack of imported [modules][Module].
#[inline(always)]
#[must_use]
pub fn len(&self) -> usize {
self.keys.len()
}
/// Is this stack of imported [modules][Module] empty?
#[inline(always)]
#[must_use]
pub fn is_empty(&self) -> bool {
self.keys.is_empty()
}
/// Get the imported [module][Module] at a particular index.
#[inline(always)]
#[must_use]
pub fn get(&self, index: usize) -> Option<Shared<Module>> {
self.modules.get(index).cloned()
}
/// Get the imported [module][Module] at a particular index.
#[allow(dead_code)]
#[inline(always)]
#[must_use]
pub(crate) fn get_mut(&mut self, index: usize) -> Option<&mut Shared<Module>> {
self.modules.get_mut(index)
}
/// Get the index of an imported [module][Module] by name.
#[inline(always)]
#[must_use]
pub fn find(&self, name: &str) -> Option<usize> {
self.keys
.iter()
.enumerate()
.rev()
.find_map(|(i, key)| if key == name { Some(i) } else { None })
}
/// Push an imported [module][Module] onto the stack.
#[inline(always)]
pub fn push(&mut self, name: impl Into<Identifier>, module: impl Into<Shared<Module>>) {
self.keys.push(name.into());
self.modules.push(module.into());
}
/// Truncate the stack of imported [modules][Module] to a particular length.
#[inline(always)]
pub fn truncate(&mut self, size: usize) {
self.keys.truncate(size);
self.modules.truncate(size);
}
/// Get an iterator to this stack of imported [modules][Module] in reverse order.
#[allow(dead_code)]
#[inline(always)]
pub fn iter(&self) -> impl Iterator<Item = (&str, &Module)> {
self.keys
.iter()
.zip(self.modules.iter())
.rev()
.map(|(name, module)| (name.as_str(), module.as_ref()))
}
/// Get an iterator to this stack of imported [modules][Module] in reverse order.
#[allow(dead_code)]
#[inline(always)]
pub(crate) fn iter_raw(&self) -> impl Iterator<Item = (&Identifier, &Shared<Module>)> {
self.keys.iter().rev().zip(self.modules.iter().rev())
}
/// Get an iterator to this stack of imported [modules][Module] in forward order.
#[allow(dead_code)]
#[inline(always)]
pub(crate) fn scan_raw(&self) -> impl Iterator<Item = (&Identifier, &Shared<Module>)> {
self.keys.iter().zip(self.modules.iter())
}
/// Does the specified function hash key exist in this stack of imported [modules][Module]?
#[allow(dead_code)]
#[inline(always)]
#[must_use]
pub fn contains_fn(&self, hash: u64) -> bool {
self.modules.iter().any(|m| m.contains_qualified_fn(hash))
}
/// Get the specified function via its hash key from this stack of imported [modules][Module].
#[inline(always)]
#[must_use]
pub fn get_fn(&self, hash: u64) -> Option<(&CallableFunction, Option<&Identifier>)> {
self.modules
.iter()
.rev()
.find_map(|m| m.get_qualified_fn(hash).map(|f| (f, m.id_raw())))
}
/// Does the specified [`TypeId`][std::any::TypeId] iterator exist in this stack of
/// imported [modules][Module]?
#[allow(dead_code)]
#[inline(always)]
#[must_use]
pub fn contains_iter(&self, id: TypeId) -> bool {
self.modules.iter().any(|m| m.contains_qualified_iter(id))
}
/// Get the specified [`TypeId`][std::any::TypeId] iterator from this stack of imported
/// [modules][Module].
#[inline(always)]
#[must_use]
pub fn get_iter(&self, id: TypeId) -> Option<IteratorFn> {
self.modules
.iter()
.rev()
.find_map(|m| m.get_qualified_iter(id))
}
}
impl IntoIterator for Imports {
type Item = (Identifier, Shared<Module>);
type IntoIter =
Zip<Rev<smallvec::IntoIter<[Identifier; 4]>>, Rev<smallvec::IntoIter<[Shared<Module>; 4]>>>;
#[inline(always)]
fn into_iter(self) -> Self::IntoIter {
self.keys
.into_iter()
.rev()
.zip(self.modules.into_iter().rev())
}
}
impl<K: Into<Identifier>, M: Into<Shared<Module>>> FromIterator<(K, M)> for Imports {
fn from_iter<T: IntoIterator<Item = (K, M)>>(iter: T) -> Self {
let mut lib = Self::new();
lib.extend(iter);
lib
}
}
impl<K: Into<Identifier>, M: Into<Shared<Module>>> Extend<(K, M)> for Imports {
fn extend<T: IntoIterator<Item = (K, M)>>(&mut self, iter: T) {
iter.into_iter().for_each(|(k, m)| {
self.keys.push(k.into());
self.modules.push(m.into());
})
}
}
impl fmt::Debug for Imports {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("Imports")?;
if self.is_empty() {
f.debug_map().finish()
} else {
f.debug_map()
.entries(self.keys.iter().zip(self.modules.iter()))
.finish()
}
}
}
#[cfg(not(feature = "unchecked"))]
#[cfg(debug_assertions)]
#[cfg(not(feature = "no_function"))]
pub const MAX_CALL_STACK_DEPTH: usize = 8;
#[cfg(not(feature = "unchecked"))]
#[cfg(debug_assertions)]
pub const MAX_EXPR_DEPTH: usize = 32;
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_function"))]
#[cfg(debug_assertions)]
pub const MAX_FUNCTION_EXPR_DEPTH: usize = 16;
#[cfg(not(feature = "unchecked"))]
#[cfg(not(debug_assertions))]
#[cfg(not(feature = "no_function"))]
pub const MAX_CALL_STACK_DEPTH: usize = 64;
#[cfg(not(feature = "unchecked"))]
#[cfg(not(debug_assertions))]
pub const MAX_EXPR_DEPTH: usize = 64;
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_function"))]
#[cfg(not(debug_assertions))]
pub const MAX_FUNCTION_EXPR_DEPTH: usize = 32;
pub const MAX_DYNAMIC_PARAMETERS: usize = 16;
pub const KEYWORD_PRINT: &str = "print";
pub const KEYWORD_DEBUG: &str = "debug";
pub const KEYWORD_TYPE_OF: &str = "type_of";
pub const KEYWORD_EVAL: &str = "eval";
pub const KEYWORD_FN_PTR: &str = "Fn";
pub const KEYWORD_FN_PTR_CALL: &str = "call";
pub const KEYWORD_FN_PTR_CURRY: &str = "curry";
#[cfg(not(feature = "no_closure"))]
pub const KEYWORD_IS_SHARED: &str = "is_shared";
pub const KEYWORD_IS_DEF_VAR: &str = "is_def_var";
#[cfg(not(feature = "no_function"))]
pub const KEYWORD_IS_DEF_FN: &str = "is_def_fn";
pub const KEYWORD_THIS: &str = "this";
#[cfg(not(feature = "no_function"))]
pub const KEYWORD_GLOBAL: &str = "global";
#[cfg(not(feature = "no_object"))]
pub const FN_GET: &str = "get$";
#[cfg(not(feature = "no_object"))]
pub const FN_SET: &str = "set$";
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
pub const FN_IDX_GET: &str = "index$get$";
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
pub const FN_IDX_SET: &str = "index$set$";
#[cfg(not(feature = "no_function"))]
pub const FN_ANONYMOUS: &str = "anon$";
/// Standard equality comparison operator.
pub const OP_EQUALS: &str = "==";
/// Standard method function for containment testing.
/// The `in` operator is implemented as a call to this method.
pub const OP_CONTAINS: &str = "contains";
/// Standard concatenation operator token.
pub const TOKEN_OP_CONCAT: Token = Token::PlusAssign;
/// Method of chaining.
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
enum ChainType {
/// Indexing.
#[cfg(not(feature = "no_index"))]
Indexing,
/// Dotting.
#[cfg(not(feature = "no_object"))]
Dotting,
}
/// Value of a chaining argument.
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
#[derive(Debug, Clone, Hash)]
enum ChainArgument {
/// Dot-property access.
#[cfg(not(feature = "no_object"))]
Property(Position),
/// Arguments to a dot method call.
/// Wrapped values are the arguments plus the [position][Position] of the first argument.
#[cfg(not(feature = "no_object"))]
MethodCallArgs(StaticVec<Dynamic>, Position),
/// Index value and [position][Position].
#[cfg(not(feature = "no_index"))]
IndexValue(Dynamic, Position),
}
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
impl ChainArgument {
/// Return the index value.
#[inline(always)]
#[cfg(not(feature = "no_index"))]
#[must_use]
pub fn into_index_value(self) -> Option<Dynamic> {
match self {
Self::IndexValue(value, _) => Some(value),
#[cfg(not(feature = "no_object"))]
_ => None,
}
}
/// Return the list of method call arguments.
#[inline(always)]
#[cfg(not(feature = "no_object"))]
#[must_use]
pub fn into_fn_call_args(self) -> Option<(StaticVec<Dynamic>, Position)> {
match self {
Self::MethodCallArgs(values, pos) => Some((values, pos)),
_ => None,
}
}
}
#[cfg(not(feature = "no_object"))]
impl From<(StaticVec<Dynamic>, Position)> for ChainArgument {
#[inline(always)]
fn from((values, pos): (StaticVec<Dynamic>, Position)) -> Self {
Self::MethodCallArgs(values, pos)
}
}
#[cfg(not(feature = "no_index"))]
impl From<(Dynamic, Position)> for ChainArgument {
#[inline(always)]
fn from((value, pos): (Dynamic, Position)) -> Self {
Self::IndexValue(value, pos)
}
}
/// Get the chaining type for an [`Expr`].
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
fn match_chaining_type(expr: &Expr) -> ChainType {
match expr {
#[cfg(not(feature = "no_index"))]
Expr::Index(_, _, _) => ChainType::Indexing,
#[cfg(not(feature = "no_object"))]
Expr::Dot(_, _, _) => ChainType::Dotting,
_ => unreachable!("`expr` should only be `Index` or `Dot`, but got {:?}", expr),
}
}
/// A type that encapsulates a mutation target for an expression with side effects.
#[derive(Debug)]
pub enum Target<'a> {
/// The target is a mutable reference to a `Dynamic` value somewhere.
RefMut(&'a mut Dynamic),
/// The target is a mutable reference to a Shared `Dynamic` value.
/// It holds both the access guard and the original shared value.
#[cfg(not(feature = "no_closure"))]
LockGuard((crate::dynamic::DynamicWriteLock<'a, Dynamic>, Dynamic)),
/// The target is a temporary `Dynamic` value (i.e. the mutation can cause no side effects).
TempValue(Dynamic),
/// The target is a bit inside an [`INT`][crate::INT].
/// This is necessary because directly pointing to a bit inside an [`INT`][crate::INT] is impossible.
#[cfg(not(feature = "no_index"))]
BitField(&'a mut Dynamic, usize, Dynamic),
/// The target is a character inside a String.
/// This is necessary because directly pointing to a char inside a String is impossible.
#[cfg(not(feature = "no_index"))]
StringChar(&'a mut Dynamic, usize, Dynamic),
}
impl<'a> Target<'a> {
/// Is the `Target` a reference pointing to other data?
#[allow(dead_code)]
#[inline]
#[must_use]
pub const fn is_ref(&self) -> bool {
match self {
Self::RefMut(_) => true,
#[cfg(not(feature = "no_closure"))]
Self::LockGuard(_) => true,
Self::TempValue(_) => false,
#[cfg(not(feature = "no_index"))]
Self::BitField(_, _, _) => false,
#[cfg(not(feature = "no_index"))]
Self::StringChar(_, _, _) => false,
}
}
/// Is the `Target` a temp value?
#[inline]
#[must_use]
pub const fn is_temp_value(&self) -> bool {
match self {
Self::RefMut(_) => false,
#[cfg(not(feature = "no_closure"))]
Self::LockGuard(_) => false,
Self::TempValue(_) => true,
#[cfg(not(feature = "no_index"))]
Self::BitField(_, _, _) => false,
#[cfg(not(feature = "no_index"))]
Self::StringChar(_, _, _) => false,
}
}
/// Is the `Target` a shared value?
#[cfg(not(feature = "no_closure"))]
#[inline]
#[must_use]
pub fn is_shared(&self) -> bool {
match self {
Self::RefMut(r) => r.is_shared(),
#[cfg(not(feature = "no_closure"))]
Self::LockGuard(_) => true,
Self::TempValue(r) => r.is_shared(),
#[cfg(not(feature = "no_index"))]
Self::BitField(_, _, _) => false,
#[cfg(not(feature = "no_index"))]
Self::StringChar(_, _, _) => false,
}
}
/// Is the `Target` a specific type?
#[allow(dead_code)]
#[inline]
#[must_use]
pub fn is<T: Variant + Clone>(&self) -> bool {
match self {
Self::RefMut(r) => r.is::<T>(),
#[cfg(not(feature = "no_closure"))]
Self::LockGuard((r, _)) => r.is::<T>(),
Self::TempValue(r) => r.is::<T>(),
#[cfg(not(feature = "no_index"))]
Self::BitField(_, _, _) => TypeId::of::<T>() == TypeId::of::<bool>(),
#[cfg(not(feature = "no_index"))]
Self::StringChar(_, _, _) => TypeId::of::<T>() == TypeId::of::<char>(),
}
}
/// Get the value of the `Target` as a `Dynamic`, cloning a referenced value if necessary.
#[inline]
#[must_use]
pub fn take_or_clone(self) -> Dynamic {
match self {
Self::RefMut(r) => r.clone(), // Referenced value is cloned
#[cfg(not(feature = "no_closure"))]
Self::LockGuard((_, orig)) => orig, // Original value is simply taken
Self::TempValue(v) => v, // Owned value is simply taken
#[cfg(not(feature = "no_index"))]
Self::BitField(_, _, value) => value, // Boolean is taken
#[cfg(not(feature = "no_index"))]
Self::StringChar(_, _, ch) => ch, // Character is taken
}
}
/// Take a `&mut Dynamic` reference from the `Target`.
#[inline(always)]
#[must_use]
pub fn take_ref(self) -> Option<&'a mut Dynamic> {
match self {
Self::RefMut(r) => Some(r),
_ => None,
}
}
/// Convert a shared or reference `Target` into a target with an owned value.
#[inline(always)]
#[must_use]
pub fn into_owned(self) -> Target<'static> {
self.take_or_clone().into()
}
/// Propagate a changed value back to the original source.
/// This has no effect except for string indexing.
#[inline]
pub fn propagate_changed_value(&mut self) -> Result<(), Box<EvalAltResult>> {
match self {
Self::RefMut(_) | Self::TempValue(_) => (),
#[cfg(not(feature = "no_closure"))]
Self::LockGuard(_) => (),
#[cfg(not(feature = "no_index"))]
Self::BitField(value, index, new_val) => {
// Replace the bit at the specified index position
let new_bit = new_val.as_bool().map_err(|err| {
Box::new(EvalAltResult::ErrorMismatchDataType(
"bool".to_string(),
err.to_string(),
Position::NONE,
))
})?;
let value = &mut *value
.write_lock::<crate::INT>()
.expect("never fails because `BitField` always holds an `INT`");
let index = *index;
if index < std::mem::size_of_val(value) * 8 {
let mask = 1 << index;
if new_bit {
*value |= mask;
} else {
*value &= !mask;
}
} else {
unreachable!("bit-field index out of bounds: {}", index);
}
}
#[cfg(not(feature = "no_index"))]
Self::StringChar(s, index, new_val) => {
// Replace the character at the specified index position
let new_ch = new_val.as_char().map_err(|err| {
Box::new(EvalAltResult::ErrorMismatchDataType(
"char".to_string(),
err.to_string(),
Position::NONE,
))
})?;
let s = &mut *s
.write_lock::<ImmutableString>()
.expect("never fails because `StringChar` always holds an `ImmutableString`");
let index = *index;
*s = s
.chars()
.enumerate()
.map(|(i, ch)| if i == index { new_ch } else { ch })
.collect();
}
}
Ok(())
}
}
impl<'a> From<&'a mut Dynamic> for Target<'a> {
#[inline]
fn from(value: &'a mut Dynamic) -> Self {
#[cfg(not(feature = "no_closure"))]
if value.is_shared() {
// Cloning is cheap for a shared value
let container = value.clone();
return Self::LockGuard((
value
.write_lock::<Dynamic>()
.expect("never fails when casting to `Dynamic`"),
container,
));
}
Self::RefMut(value)
}
}
impl Deref for Target<'_> {
type Target = Dynamic;
#[inline]
fn deref(&self) -> &Dynamic {
match self {
Self::RefMut(r) => *r,
#[cfg(not(feature = "no_closure"))]
Self::LockGuard((r, _)) => &**r,
Self::TempValue(ref r) => r,
#[cfg(not(feature = "no_index"))]
Self::BitField(_, _, ref r) => r,
#[cfg(not(feature = "no_index"))]
Self::StringChar(_, _, ref r) => r,
}
}
}
impl AsRef<Dynamic> for Target<'_> {
#[inline(always)]
fn as_ref(&self) -> &Dynamic {
self
}
}
impl DerefMut for Target<'_> {
#[inline]
fn deref_mut(&mut self) -> &mut Dynamic {
match self {
Self::RefMut(r) => *r,
#[cfg(not(feature = "no_closure"))]
Self::LockGuard((r, _)) => r.deref_mut(),
Self::TempValue(ref mut r) => r,
#[cfg(not(feature = "no_index"))]
Self::BitField(_, _, ref mut r) => r,
#[cfg(not(feature = "no_index"))]
Self::StringChar(_, _, ref mut r) => r,
}
}
}
impl AsMut<Dynamic> for Target<'_> {
#[inline(always)]
fn as_mut(&mut self) -> &mut Dynamic {
self
}
}
impl<T: Into<Dynamic>> From<T> for Target<'_> {
#[inline(always)]
#[must_use]
fn from(value: T) -> Self {
Self::TempValue(value.into())
}
}
/// _(internals)_ An entry in a function resolution cache.
/// Exported under the `internals` feature only.
///
/// # Volatile Data Structure
///
/// This type is volatile and may change.
#[derive(Debug, Clone)]
pub struct FnResolutionCacheEntry {
/// Function.
pub func: CallableFunction,
/// Optional source.
pub source: Option<Identifier>,
}
/// _(internals)_ A function resolution cache.
/// Exported under the `internals` feature only.
///
/// # Volatile Data Structure
///
/// This type is volatile and may change.
pub type FnResolutionCache = BTreeMap<u64, Option<Box<FnResolutionCacheEntry>>>;
/// _(internals)_ A type that holds all the current states of the [`Engine`].
/// Exported under the `internals` feature only.
///
/// # Volatile Data Structure
///
/// This type is volatile and may change.
#[derive(Debug, Clone, Default)]
pub struct EvalState {
/// Source of the current context.
pub source: Option<Identifier>,
/// Normally, access to variables are parsed with a relative offset into the [`Scope`] to avoid a lookup.
/// In some situation, e.g. after running an `eval` statement, or after a custom syntax statement,
/// subsequent offsets may become mis-aligned.
/// When that happens, this flag is turned on to force a [`Scope`] search by name.
pub always_search_scope: bool,
/// Level of the current scope. The global (root) level is zero, a new block (or function call)
/// is one level higher, and so on.
pub scope_level: usize,
/// Number of operations performed.
pub num_operations: u64,
/// Number of modules loaded.
pub num_modules: usize,
/// Embedded module resolver.
#[cfg(not(feature = "no_module"))]
pub embedded_module_resolver: Option<Shared<crate::module::resolvers::StaticModuleResolver>>,
/// Stack of function resolution caches.
fn_resolution_caches: Vec<FnResolutionCache>,
}
impl EvalState {
/// Create a new [`EvalState`].
#[inline(always)]
#[must_use]
pub const fn new() -> Self {
Self {
source: None,
always_search_scope: false,
scope_level: 0,
num_operations: 0,
num_modules: 0,
#[cfg(not(feature = "no_module"))]
embedded_module_resolver: None,
fn_resolution_caches: Vec::new(),
}
}
/// Is the state currently at global (root) level?
#[inline(always)]
#[must_use]
pub const fn is_global(&self) -> bool {
self.scope_level == 0
}
/// Get a mutable reference to the current function resolution cache.
#[inline(always)]
#[must_use]
pub fn fn_resolution_cache_mut(&mut self) -> &mut FnResolutionCache {
if self.fn_resolution_caches.is_empty() {
// Push a new function resolution cache if the stack is empty
self.fn_resolution_caches.push(Default::default());
}
self.fn_resolution_caches.last_mut().expect(
"never fails because there is at least one function resolution cache by this point",
)
}
/// Push an empty function resolution cache onto the stack and make it current.
#[allow(dead_code)]
#[inline(always)]
pub fn push_fn_resolution_cache(&mut self) {
self.fn_resolution_caches.push(Default::default());
}
/// Remove the current function resolution cache from the stack and make the last one current.
///
/// # Panics
///
/// Panics if there are no more function resolution cache in the stack.
#[inline(always)]
pub fn pop_fn_resolution_cache(&mut self) {
self.fn_resolution_caches
.pop()
.expect("there should be at least one function resolution cache");
}
}
/// _(internals)_ A type containing all the limits imposed by the [`Engine`].
/// Exported under the `internals` feature only.
///
/// # Volatile Data Structure
///
/// This type is volatile and may change.
#[cfg(not(feature = "unchecked"))]
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub struct Limits {
/// Maximum levels of call-stack to prevent infinite recursion.
///
/// Set to zero to effectively disable function calls.
///
/// Not available under `no_function`.
#[cfg(not(feature = "no_function"))]
pub max_call_stack_depth: usize,
/// Maximum depth of statements/expressions at global level.
pub max_expr_depth: Option<NonZeroUsize>,
/// Maximum depth of statements/expressions in functions.
///
/// Not available under `no_function`.
#[cfg(not(feature = "no_function"))]
pub max_function_expr_depth: Option<NonZeroUsize>,
/// Maximum number of operations allowed to run.
pub max_operations: Option<std::num::NonZeroU64>,
/// Maximum number of [modules][Module] allowed to load.
///
/// Set to zero to effectively disable loading any [module][Module].
///
/// Not available under `no_module`.
#[cfg(not(feature = "no_module"))]
pub max_modules: usize,
/// Maximum length of a [string][ImmutableString].
pub max_string_size: Option<NonZeroUsize>,
/// Maximum length of an [array][Array].
///
/// Not available under `no_index`.
#[cfg(not(feature = "no_index"))]
pub max_array_size: Option<NonZeroUsize>,
/// Maximum number of properties in an [object map][Map].
///
/// Not available under `no_object`.
#[cfg(not(feature = "no_object"))]
pub max_map_size: Option<NonZeroUsize>,
}
#[cfg(not(feature = "unchecked"))]
impl Default for Limits {
fn default() -> Self {
Self {
#[cfg(not(feature = "no_function"))]
max_call_stack_depth: MAX_CALL_STACK_DEPTH,
max_expr_depth: NonZeroUsize::new(MAX_EXPR_DEPTH),
#[cfg(not(feature = "no_function"))]
max_function_expr_depth: NonZeroUsize::new(MAX_FUNCTION_EXPR_DEPTH),
max_operations: None,
#[cfg(not(feature = "no_module"))]
max_modules: usize::MAX,
max_string_size: None,
#[cfg(not(feature = "no_index"))]
max_array_size: None,
#[cfg(not(feature = "no_object"))]
max_map_size: None,
}
}
}
/// Context of a script evaluation process.
#[derive(Debug)]
pub struct EvalContext<'a, 'x, 'px, 'm, 's, 'b, 't, 'pt> {
pub(crate) engine: &'a Engine,
pub(crate) scope: &'x mut Scope<'px>,
pub(crate) mods: &'m mut Imports,
pub(crate) state: &'s mut EvalState,
pub(crate) lib: &'b [&'b Module],
pub(crate) this_ptr: &'t mut Option<&'pt mut Dynamic>,
pub(crate) level: usize,
}
impl<'x, 'px, 'pt> EvalContext<'_, 'x, 'px, '_, '_, '_, '_, 'pt> {
/// The current [`Engine`].
#[inline(always)]
#[must_use]
pub const fn engine(&self) -> &Engine {
self.engine
}
/// The current source.
#[inline(always)]
#[must_use]
pub fn source(&self) -> Option<&str> {
self.state.source.as_ref().map(|s| s.as_str())
}
/// The current [`Scope`].
#[inline(always)]
#[must_use]
pub const fn scope(&self) -> &Scope<'px> {
self.scope
}
/// Mutable reference to the current [`Scope`].
#[inline(always)]
#[must_use]
pub fn scope_mut(&mut self) -> &mut &'x mut Scope<'px> {
&mut self.scope
}
/// Get an iterator over the current set of modules imported via `import` statements.
#[cfg(not(feature = "no_module"))]
#[inline(always)]
pub fn iter_imports(&self) -> impl Iterator<Item = (&str, &Module)> {
self.mods.iter()
}
/// _(internals)_ The current set of modules imported via `import` statements.
/// Exported under the `internals` feature only.
#[cfg(feature = "internals")]
#[cfg(not(feature = "no_module"))]
#[inline(always)]
#[must_use]
pub const fn imports(&self) -> &Imports {
self.mods
}
/// Get an iterator over the namespaces containing definition of all script-defined functions.
#[inline(always)]
pub fn iter_namespaces(&self) -> impl Iterator<Item = &Module> {
self.lib.iter().cloned()
}
/// _(internals)_ The current set of namespaces containing definitions of all script-defined functions.
/// Exported under the `internals` feature only.
#[cfg(feature = "internals")]
#[inline(always)]
#[must_use]
pub const fn namespaces(&self) -> &[&Module] {
self.lib
}
/// The current bound `this` pointer, if any.
#[inline(always)]
#[must_use]
pub fn this_ptr(&self) -> Option<&Dynamic> {
self.this_ptr.as_ref().map(|v| &**v)
}
/// Mutable reference to the current bound `this` pointer, if any.
#[inline(always)]
#[must_use]
pub fn this_ptr_mut(&mut self) -> Option<&mut &'pt mut Dynamic> {
self.this_ptr.as_mut()
}
/// The current nesting level of function calls.
#[inline(always)]
#[must_use]
pub const fn call_level(&self) -> usize {
self.level
}
}
/// Rhai main scripting engine.
///
/// # Thread Safety
///
/// [`Engine`] is re-entrant.
///
/// Currently, [`Engine`] is neither [`Send`] nor [`Sync`].
/// Use the `sync` feature to make it [`Send`] `+` [`Sync`].
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::Engine;
///
/// let engine = Engine::new();
///
/// let result = engine.eval::<i64>("40 + 2")?;
///
/// println!("Answer: {}", result); // prints 42
/// # Ok(())
/// # }
/// ```
pub struct Engine {
/// A module containing all functions directly loaded into the Engine.
pub(crate) global_namespace: Module,
/// A collection of all modules loaded into the global namespace of the Engine.
pub(crate) global_modules: StaticVec<Shared<Module>>,
/// A collection of all sub-modules directly loaded into the Engine.
pub(crate) global_sub_modules: BTreeMap<Identifier, Shared<Module>>,
/// A module resolution service.
#[cfg(not(feature = "no_module"))]
pub(crate) module_resolver: Option<Box<dyn crate::ModuleResolver>>,
/// A map mapping type names to pretty-print names.
pub(crate) type_names: BTreeMap<Identifier, Box<Identifier>>,
/// An empty [`ImmutableString`] for cloning purposes.
pub(crate) empty_string: ImmutableString,
/// A set of symbols to disable.
pub(crate) disabled_symbols: BTreeSet<Identifier>,
/// A map containing custom keywords and precedence to recognize.
pub(crate) custom_keywords: BTreeMap<Identifier, Option<Precedence>>,
/// Custom syntax.
pub(crate) custom_syntax: BTreeMap<Identifier, Box<CustomSyntax>>,
/// Callback closure for resolving variable access.
pub(crate) resolve_var: Option<OnVarCallback>,
/// Callback closure for implementing the `print` command.
pub(crate) print: Option<OnPrintCallback>,
/// Callback closure for implementing the `debug` command.
pub(crate) debug: Option<OnDebugCallback>,
/// Callback closure for progress reporting.
#[cfg(not(feature = "unchecked"))]
pub(crate) progress: Option<crate::fn_native::OnProgressCallback>,
/// Optimize the AST after compilation.
pub(crate) optimization_level: OptimizationLevel,
/// Max limits.
#[cfg(not(feature = "unchecked"))]
pub(crate) limits: Limits,
}
impl fmt::Debug for Engine {
#[inline(always)]
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("Engine")
}
}
impl Default for Engine {
#[inline(always)]
fn default() -> Self {
Self::new()
}
}
/// Make getter function
#[cfg(not(feature = "no_object"))]
#[inline]
#[must_use]
pub fn make_getter(id: &str) -> String {
format!("{}{}", FN_GET, id)
}
/// Make setter function
#[cfg(not(feature = "no_object"))]
#[inline]
#[must_use]
pub fn make_setter(id: &str) -> String {
format!("{}{}", FN_SET, id)
}
/// Is this function an anonymous function?
#[cfg(not(feature = "no_function"))]
#[inline(always)]
#[must_use]
pub fn is_anonymous_fn(fn_name: &str) -> bool {
fn_name.starts_with(FN_ANONYMOUS)
}
/// Print to `stdout`
#[inline]
#[allow(unused_variables)]
fn print_to_stdout(s: &str) {
#[cfg(not(feature = "no_std"))]
#[cfg(not(any(target_arch = "wasm32", target_arch = "wasm64")))]
println!("{}", s);
}
/// Debug to `stdout`
#[inline]
#[allow(unused_variables)]
fn debug_to_stdout(s: &str, source: Option<&str>, pos: Position) {
#[cfg(not(feature = "no_std"))]
#[cfg(not(any(target_arch = "wasm32", target_arch = "wasm64")))]
if let Some(source) = source {
println!("{}{:?} | {}", source, pos, s);
} else if pos.is_none() {
println!("{}", s);
} else {
println!("{:?} | {}", pos, s);
}
}
impl Engine {
/// Create a new [`Engine`].
#[inline]
#[must_use]
pub fn new() -> Self {
// Create the new scripting Engine
let mut engine = Self::new_raw();
#[cfg(not(feature = "no_module"))]
#[cfg(not(feature = "no_std"))]
#[cfg(not(any(target_arch = "wasm32", target_arch = "wasm64")))]
{
engine.module_resolver =
Some(Box::new(crate::module::resolvers::FileModuleResolver::new()));
}
// default print/debug implementations
engine.print = Some(Box::new(print_to_stdout));
engine.debug = Some(Box::new(debug_to_stdout));
engine.register_global_module(StandardPackage::new().as_shared_module());
engine
}
/// Create a new [`Engine`] with minimal built-in functions.
///
/// Use [`register_global_module`][Engine::register_global_module] to add packages of functions.
#[inline]
#[must_use]
pub fn new_raw() -> Self {
let mut engine = Self {
global_namespace: Default::default(),
global_modules: Default::default(),
global_sub_modules: Default::default(),
#[cfg(not(feature = "no_module"))]
module_resolver: None,
type_names: Default::default(),
empty_string: Default::default(),
disabled_symbols: Default::default(),
custom_keywords: Default::default(),
custom_syntax: Default::default(),
resolve_var: None,
print: None,
debug: None,
#[cfg(not(feature = "unchecked"))]
progress: None,
optimization_level: Default::default(),
#[cfg(not(feature = "unchecked"))]
limits: Default::default(),
};
engine.global_namespace.internal = true;
engine
}
/// Search for a module within an imports stack.
#[inline]
#[must_use]
pub(crate) fn search_imports(
&self,
mods: &Imports,
state: &mut EvalState,
namespace: &NamespaceRef,
) -> Option<Shared<Module>> {
let root = &namespace[0].name;
// Qualified - check if the root module is directly indexed
let index = if state.always_search_scope {
None
} else {
namespace.index()
};
if let Some(index) = index {
let offset = mods.len() - index.get();
Some(
mods.get(offset)
.expect("never fails because offset should be within range"),
)
} else {
mods.find(root)
.map(|n| {
mods.get(n)
.expect("never fails because the index came from `find`")
})
.or_else(|| self.global_sub_modules.get(root).cloned())
}
}
/// Search for a variable within the scope or within imports,
/// depending on whether the variable name is namespace-qualified.
pub(crate) fn search_namespace<'s>(
&self,
scope: &'s mut Scope,
mods: &mut Imports,
state: &mut EvalState,
lib: &[&Module],
this_ptr: &'s mut Option<&mut Dynamic>,
expr: &Expr,
) -> Result<(Target<'s>, Position), Box<EvalAltResult>> {
match expr {
Expr::Variable(Some(_), _, _) => {
self.search_scope_only(scope, mods, state, lib, this_ptr, expr)
}
Expr::Variable(None, var_pos, v) => match v.as_ref() {
// Normal variable access
(_, None, _) => self.search_scope_only(scope, mods, state, lib, this_ptr, expr),
// Qualified variable
(_, Some((namespace, hash_var)), var_name) => {
let module = self.search_imports(mods, state, namespace).ok_or_else(|| {
EvalAltResult::ErrorModuleNotFound(
namespace[0].name.to_string(),
namespace[0].pos,
)
})?;
let target = module.get_qualified_var(*hash_var).map_err(|mut err| {
match *err {
EvalAltResult::ErrorVariableNotFound(ref mut err_name, _) => {
*err_name = format!("{}{}", namespace, var_name);
}
_ => (),
}
err.fill_position(*var_pos)
})?;
// Module variables are constant
let mut target = target.clone();
target.set_access_mode(AccessMode::ReadOnly);
Ok((target.into(), *var_pos))
}
},
_ => unreachable!("Expr::Variable expected, but gets {:?}", expr),
}
}
/// Search for a variable within the scope
///
/// # Panics
///
/// Panics if `expr` is not [`Expr::Variable`].
pub(crate) fn search_scope_only<'s>(
&self,
scope: &'s mut Scope,
mods: &mut Imports,
state: &mut EvalState,
lib: &[&Module],
this_ptr: &'s mut Option<&mut Dynamic>,
expr: &Expr,
) -> Result<(Target<'s>, Position), Box<EvalAltResult>> {
// Make sure that the pointer indirection is taken only when absolutely necessary.
let (index, var_pos) = match expr {
// Check if the variable is `this`
Expr::Variable(None, pos, v) if v.0.is_none() && v.2 == KEYWORD_THIS => {
return if let Some(val) = this_ptr {
Ok(((*val).into(), *pos))
} else {
EvalAltResult::ErrorUnboundThis(*pos).into()
}
}
_ if state.always_search_scope => (0, expr.position()),
Expr::Variable(Some(i), pos, _) => (i.get() as usize, *pos),
Expr::Variable(None, pos, v) => (v.0.map(NonZeroUsize::get).unwrap_or(0), *pos),
_ => unreachable!("Expr::Variable expected, but gets {:?}", expr),
};
// Check the variable resolver, if any
if let Some(ref resolve_var) = self.resolve_var {
let context = EvalContext {
engine: self,
scope,
mods,
state,
lib,
this_ptr,
level: 0,
};
match resolve_var(
expr.get_variable_name(true)
.expect("`expr` should be `Variable`"),
index,
&context,
) {
Ok(Some(mut result)) => {
result.set_access_mode(AccessMode::ReadOnly);
return Ok((result.into(), var_pos));
}
Ok(None) => (),
Err(err) => return Err(err.fill_position(var_pos)),
}
}
let index = if index > 0 {
scope.len() - index
} else {
// Find the variable in the scope
let var_name = expr
.get_variable_name(true)
.expect("`expr` should be `Variable`");
scope
.get_index(var_name)
.ok_or_else(|| EvalAltResult::ErrorVariableNotFound(var_name.to_string(), var_pos))?
.0
};
let val = scope.get_mut_by_index(index);
Ok((val.into(), var_pos))
}
/// Chain-evaluate a dot/index chain.
/// [`Position`] in [`EvalAltResult`] is [`NONE`][Position::NONE] and must be set afterwards.
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
fn eval_dot_index_chain_helper(
&self,
mods: &mut Imports,
state: &mut EvalState,
lib: &[&Module],
this_ptr: &mut Option<&mut Dynamic>,
target: &mut Target,
root: (&str, Position),
rhs: &Expr,
terminate_chaining: bool,
idx_values: &mut StaticVec<ChainArgument>,
chain_type: ChainType,
level: usize,
new_val: Option<((Dynamic, Position), (Option<OpAssignment>, Position))>,
) -> Result<(Dynamic, bool), Box<EvalAltResult>> {
let is_ref_mut = target.is_ref();
let _terminate_chaining = terminate_chaining;
// Pop the last index value
let idx_val = idx_values
.pop()
.expect("never fails because an index chain is never empty");
match chain_type {
#[cfg(not(feature = "no_index"))]
ChainType::Indexing => {
let pos = rhs.position();
let idx_val = idx_val
.into_index_value()
.expect("never fails because `chain_type` is `ChainType::Index`");
match rhs {
// xxx[idx].expr... | xxx[idx][expr]...
Expr::Dot(x, term, x_pos) | Expr::Index(x, term, x_pos)
if !_terminate_chaining =>
{
let idx_pos = x.lhs.position();
let obj_ptr = &mut self.get_indexed_mut(
mods, state, lib, target, idx_val, idx_pos, false, true, level,
)?;
let rhs_chain = match_chaining_type(rhs);
self.eval_dot_index_chain_helper(
mods, state, lib, this_ptr, obj_ptr, root, &x.rhs, *term, idx_values,
rhs_chain, level, new_val,
)
.map_err(|err| err.fill_position(*x_pos))
}
// xxx[rhs] op= new_val
_ if new_val.is_some() => {
let ((new_val, new_pos), (op_info, op_pos)) =
new_val.expect("never fails because `new_val` is `Some`");
let mut idx_val_for_setter = idx_val.clone();
let try_setter = match self.get_indexed_mut(
mods, state, lib, target, idx_val, pos, true, false, level,
) {
// Indexed value is a reference - update directly
Ok(ref mut obj_ptr) => {
self.eval_op_assignment(
mods, state, lib, op_info, op_pos, obj_ptr, root, new_val,
)
.map_err(|err| err.fill_position(new_pos))?;
None
}
// Can't index - try to call an index setter
#[cfg(not(feature = "no_index"))]
Err(err) if matches!(*err, EvalAltResult::ErrorIndexingType(_, _)) => {
Some(new_val)
}
// Any other error
Err(err) => return Err(err),
};
if let Some(mut new_val) = try_setter {
// Try to call index setter
let hash_set =
FnCallHashes::from_native(crate::calc_fn_hash(FN_IDX_SET, 3));
let args = &mut [target, &mut idx_val_for_setter, &mut new_val];
let pos = Position::NONE;
self.exec_fn_call(
mods, state, lib, FN_IDX_SET, hash_set, args, is_ref_mut, true,
pos, None, level,
)?;
}
self.check_data_size(target.as_ref())
.map_err(|err| err.fill_position(root.1))?;
Ok((Dynamic::UNIT, true))
}
// xxx[rhs]
_ => self
.get_indexed_mut(mods, state, lib, target, idx_val, pos, false, true, level)
.map(|v| (v.take_or_clone(), false)),
}
}
#[cfg(not(feature = "no_object"))]
ChainType::Dotting => {
match rhs {
// xxx.fn_name(arg_expr_list)
Expr::FnCall(x, pos) if !x.is_qualified() && new_val.is_none() => {
let FnCallExpr { name, hashes, .. } = x.as_ref();
let call_args = &mut idx_val
.into_fn_call_args()
.expect("never fails because `chain_type` is `ChainType::Dot` with `Expr::FnCallExpr`");
self.make_method_call(
mods, state, lib, name, *hashes, target, call_args, *pos, level,
)
}
// xxx.fn_name(...) = ???
Expr::FnCall(_, _) if new_val.is_some() => {
unreachable!("method call cannot be assigned to")
}
// xxx.module::fn_name(...) - syntax error
Expr::FnCall(_, _) => {
unreachable!("function call in dot chain should not be namespace-qualified")
}
// {xxx:map}.id op= ???
Expr::Property(x) if target.is::<Map>() && new_val.is_some() => {
let (name, pos) = &x.2;
let ((new_val, new_pos), (op_info, op_pos)) =
new_val.expect("never fails because `new_val` is `Some`");
let index = name.into();
{
let val_target = &mut self.get_indexed_mut(
mods, state, lib, target, index, *pos, true, false, level,
)?;
self.eval_op_assignment(
mods, state, lib, op_info, op_pos, val_target, root, new_val,
)
.map_err(|err| err.fill_position(new_pos))?;
}
self.check_data_size(target.as_ref())
.map_err(|err| err.fill_position(root.1))?;
Ok((Dynamic::UNIT, true))
}
// {xxx:map}.id
Expr::Property(x) if target.is::<Map>() => {
let (name, pos) = &x.2;
let index = name.into();
let val = self.get_indexed_mut(
mods, state, lib, target, index, *pos, false, false, level,
)?;
Ok((val.take_or_clone(), false))
}
// xxx.id op= ???
Expr::Property(x) if new_val.is_some() => {
let ((getter, hash_get), (setter, hash_set), (name, pos)) = x.as_ref();
let ((mut new_val, new_pos), (op_info, op_pos)) =
new_val.expect("never fails because `new_val` is `Some`");
if op_info.is_some() {
let hash = FnCallHashes::from_native(*hash_get);
let args = &mut [target.as_mut()];
let (mut orig_val, _) = self
.exec_fn_call(
mods, state, lib, getter, hash, args, is_ref_mut, true, *pos,
None, level,
)
.or_else(|err| match *err {
// Try an indexer if property does not exist
EvalAltResult::ErrorDotExpr(_, _) => {
let prop = name.into();
self.get_indexed_mut(
mods, state, lib, target, prop, *pos, false, true,
level,
)
.map(|v| (v.take_or_clone(), false))
.map_err(
|idx_err| match *idx_err {
EvalAltResult::ErrorIndexingType(_, _) => err,
_ => idx_err,
},
)
}
_ => Err(err),
})?;
self.eval_op_assignment(
mods,
state,
lib,
op_info,
op_pos,
&mut (&mut orig_val).into(),
root,
new_val,
)
.map_err(|err| err.fill_position(new_pos))?;
self.check_data_size(target.as_ref())
.map_err(|err| err.fill_position(root.1))?;
new_val = orig_val;
}
let hash = FnCallHashes::from_native(*hash_set);
let args = &mut [target.as_mut(), &mut new_val];
self.exec_fn_call(
mods, state, lib, setter, hash, args, is_ref_mut, true, *pos, None,
level,
)
.or_else(|err| match *err {
// Try an indexer if property does not exist
EvalAltResult::ErrorDotExpr(_, _) => {
let args = &mut [target, &mut name.into(), &mut new_val];
let hash_set =
FnCallHashes::from_native(crate::calc_fn_hash(FN_IDX_SET, 3));
let pos = Position::NONE;
self.exec_fn_call(
mods, state, lib, FN_IDX_SET, hash_set, args, is_ref_mut, true,
pos, None, level,
)
.map_err(
|idx_err| match *idx_err {
EvalAltResult::ErrorIndexingType(_, _) => err,
_ => idx_err,
},
)
}
_ => Err(err),
})
}
// xxx.id
Expr::Property(x) => {
let ((getter, hash_get), _, (name, pos)) = x.as_ref();
let hash = FnCallHashes::from_native(*hash_get);
let args = &mut [target.as_mut()];
self.exec_fn_call(
mods, state, lib, getter, hash, args, is_ref_mut, true, *pos, None,
level,
)
.map_or_else(
|err| match *err {
// Try an indexer if property does not exist
EvalAltResult::ErrorDotExpr(_, _) => {
let prop = name.into();
self.get_indexed_mut(
mods, state, lib, target, prop, *pos, false, true, level,
)
.map(|v| (v.take_or_clone(), false))
.map_err(|idx_err| {
match *idx_err {
EvalAltResult::ErrorIndexingType(_, _) => err,
_ => idx_err,
}
})
}
_ => Err(err),
},
|(v, _)| Ok((v, false)),
)
}
// {xxx:map}.sub_lhs[expr] | {xxx:map}.sub_lhs.expr
Expr::Index(x, term, x_pos) | Expr::Dot(x, term, x_pos)
if target.is::<Map>() =>
{
let val_target = &mut match x.lhs {
Expr::Property(ref p) => {
let (name, pos) = &p.2;
let index = name.into();
self.get_indexed_mut(
mods, state, lib, target, index, *pos, false, true, level,
)?
}
// {xxx:map}.fn_name(arg_expr_list)[expr] | {xxx:map}.fn_name(arg_expr_list).expr
Expr::FnCall(ref x, pos) if !x.is_qualified() => {
let FnCallExpr { name, hashes, .. } = x.as_ref();
let call_args = &mut idx_val
.into_fn_call_args()
.expect("never fails because `chain_type` is `ChainType::Dot` with `Expr::FnCallExpr`");
let (val, _) = self.make_method_call(
mods, state, lib, name, *hashes, target, call_args, pos, level,
)?;
val.into()
}
// {xxx:map}.module::fn_name(...) - syntax error
Expr::FnCall(_, _) => unreachable!(
"function call in dot chain should not be namespace-qualified"
),
// Others - syntax error
ref expr => unreachable!("invalid dot expression: {:?}", expr),
};
let rhs_chain = match_chaining_type(rhs);
self.eval_dot_index_chain_helper(
mods, state, lib, this_ptr, val_target, root, &x.rhs, *term,
idx_values, rhs_chain, level, new_val,
)
.map_err(|err| err.fill_position(*x_pos))
}
// xxx.sub_lhs[expr] | xxx.sub_lhs.expr
Expr::Index(x, term, x_pos) | Expr::Dot(x, term, x_pos) => {
match x.lhs {
// xxx.prop[expr] | xxx.prop.expr
Expr::Property(ref p) => {
let ((getter, hash_get), (setter, hash_set), (name, pos)) =
p.as_ref();
let rhs_chain = match_chaining_type(rhs);
let hash_get = FnCallHashes::from_native(*hash_get);
let hash_set = FnCallHashes::from_native(*hash_set);
let mut arg_values = [target.as_mut(), &mut Default::default()];
let args = &mut arg_values[..1];
let (mut val, updated) = self
.exec_fn_call(
mods, state, lib, getter, hash_get, args, is_ref_mut, true,
*pos, None, level,
)
.or_else(|err| match *err {
// Try an indexer if property does not exist
EvalAltResult::ErrorDotExpr(_, _) => {
let prop = name.into();
self.get_indexed_mut(
mods, state, lib, target, prop, *pos, false, true,
level,
)
.map(|v| (v.take_or_clone(), false))
.map_err(
|idx_err| match *idx_err {
EvalAltResult::ErrorIndexingType(_, _) => err,
_ => idx_err,
},
)
}
_ => Err(err),
})?;
let val = &mut val;
let (result, may_be_changed) = self
.eval_dot_index_chain_helper(
mods,
state,
lib,
this_ptr,
&mut val.into(),
root,
&x.rhs,
*term,
idx_values,
rhs_chain,
level,
new_val,
)
.map_err(|err| err.fill_position(*x_pos))?;
// Feed the value back via a setter just in case it has been updated
if updated || may_be_changed {
// Re-use args because the first &mut parameter will not be consumed
let mut arg_values = [target.as_mut(), val];
let args = &mut arg_values;
self.exec_fn_call(
mods, state, lib, setter, hash_set, args, is_ref_mut, true,
*pos, None, level,
)
.or_else(
|err| match *err {
// Try an indexer if property does not exist
EvalAltResult::ErrorDotExpr(_, _) => {
let args =
&mut [target.as_mut(), &mut name.into(), val];
let hash_set = FnCallHashes::from_native(
crate::calc_fn_hash(FN_IDX_SET, 3),
);
self.exec_fn_call(
mods, state, lib, FN_IDX_SET, hash_set, args,
is_ref_mut, true, *pos, None, level,
)
.or_else(|idx_err| match *idx_err {
EvalAltResult::ErrorIndexingType(_, _) => {
// If there is no setter, no need to feed it back because
// the property is read-only
Ok((Dynamic::UNIT, false))
}
_ => Err(idx_err),
})
}
_ => Err(err),
},
)?;
self.check_data_size(target.as_ref())
.map_err(|err| err.fill_position(root.1))?;
}
Ok((result, may_be_changed))
}
// xxx.fn_name(arg_expr_list)[expr] | xxx.fn_name(arg_expr_list).expr
Expr::FnCall(ref f, pos) if !f.is_qualified() => {
let FnCallExpr { name, hashes, .. } = f.as_ref();
let rhs_chain = match_chaining_type(rhs);
let args = &mut idx_val
.into_fn_call_args()
.expect("never fails because `chain_type` is `ChainType::Dot` with `Expr::FnCallExpr`");
let (mut val, _) = self.make_method_call(
mods, state, lib, name, *hashes, target, args, pos, level,
)?;
let val = &mut val;
let target = &mut val.into();
self.eval_dot_index_chain_helper(
mods, state, lib, this_ptr, target, root, &x.rhs, *term,
idx_values, rhs_chain, level, new_val,
)
.map_err(|err| err.fill_position(pos))
}
// xxx.module::fn_name(...) - syntax error
Expr::FnCall(_, _) => unreachable!(
"function call in dot chain should not be namespace-qualified"
),
// Others - syntax error
ref expr => unreachable!("invalid dot expression: {:?}", expr),
}
}
// Syntax error
_ => EvalAltResult::ErrorDotExpr("".into(), rhs.position()).into(),
}
}
}
}
/// Evaluate a dot/index chain.
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
fn eval_dot_index_chain(
&self,
scope: &mut Scope,
mods: &mut Imports,
state: &mut EvalState,
lib: &[&Module],
this_ptr: &mut Option<&mut Dynamic>,
expr: &Expr,
level: usize,
new_val: Option<((Dynamic, Position), (Option<OpAssignment>, Position))>,
) -> RhaiResult {
let (crate::ast::BinaryExpr { lhs, rhs }, chain_type, term, op_pos) = match expr {
#[cfg(not(feature = "no_index"))]
Expr::Index(x, term, pos) => (x.as_ref(), ChainType::Indexing, *term, *pos),
#[cfg(not(feature = "no_object"))]
Expr::Dot(x, term, pos) => (x.as_ref(), ChainType::Dotting, *term, *pos),
_ => unreachable!("index or dot chain expected, but gets {:?}", expr),
};
let idx_values = &mut Default::default();
self.eval_dot_index_chain_arguments(
scope, mods, state, lib, this_ptr, rhs, term, chain_type, idx_values, 0, level,
)?;
match lhs {
// id.??? or id[???]
Expr::Variable(_, var_pos, x) => {
#[cfg(not(feature = "unchecked"))]
self.inc_operations(state, *var_pos)?;
let (mut target, _) =
self.search_namespace(scope, mods, state, lib, this_ptr, lhs)?;
let obj_ptr = &mut target;
let root = (x.2.as_str(), *var_pos);
self.eval_dot_index_chain_helper(
mods, state, lib, &mut None, obj_ptr, root, rhs, term, idx_values, chain_type,
level, new_val,
)
.map(|(v, _)| v)
.map_err(|err| err.fill_position(op_pos))
}
// {expr}.??? = ??? or {expr}[???] = ???
_ if new_val.is_some() => unreachable!("cannot assign to an expression"),
// {expr}.??? or {expr}[???]
expr => {
let value = self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?;
let obj_ptr = &mut value.into();
let root = ("", expr.position());
self.eval_dot_index_chain_helper(
mods, state, lib, this_ptr, obj_ptr, root, rhs, term, idx_values, chain_type,
level, new_val,
)
.map(|(v, _)| v)
.map_err(|err| err.fill_position(op_pos))
}
}
}
/// Evaluate a chain of indexes and store the results in a [`StaticVec`].
/// [`StaticVec`] is used to avoid an allocation in the overwhelming cases of
/// just a few levels of indexing.
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
fn eval_dot_index_chain_arguments(
&self,
scope: &mut Scope,
mods: &mut Imports,
state: &mut EvalState,
lib: &[&Module],
this_ptr: &mut Option<&mut Dynamic>,
expr: &Expr,
terminate_chaining: bool,
parent_chain_type: ChainType,
idx_values: &mut StaticVec<ChainArgument>,
size: usize,
level: usize,
) -> Result<(), Box<EvalAltResult>> {
#[cfg(not(feature = "unchecked"))]
self.inc_operations(state, expr.position())?;
let _parent_chain_type = parent_chain_type;
match expr {
#[cfg(not(feature = "no_object"))]
Expr::FnCall(x, _) if _parent_chain_type == ChainType::Dotting && !x.is_qualified() => {
let crate::ast::FnCallExpr {
args, constants, ..
} = x.as_ref();
let mut arg_values = StaticVec::with_capacity(args.len());
let mut first_arg_pos = Position::NONE;
for index in 0..args.len() {
let (value, pos) = self.get_arg_value(
scope, mods, state, lib, this_ptr, level, args, constants, index,
)?;
arg_values.push(value.flatten());
if index == 0 {
first_arg_pos = pos
}
}
idx_values.push((arg_values, first_arg_pos).into());
}
#[cfg(not(feature = "no_object"))]
Expr::FnCall(_, _) if _parent_chain_type == ChainType::Dotting => {
unreachable!("function call in dot chain should not be namespace-qualified")
}
#[cfg(not(feature = "no_object"))]
Expr::Property(x) if _parent_chain_type == ChainType::Dotting => {
idx_values.push(ChainArgument::Property((x.2).1))
}
Expr::Property(_) => unreachable!("unexpected Expr::Property for indexing"),
Expr::Index(x, term, _) | Expr::Dot(x, term, _) if !terminate_chaining => {
let crate::ast::BinaryExpr { lhs, rhs, .. } = x.as_ref();
// Evaluate in left-to-right order
let lhs_val = match lhs {
#[cfg(not(feature = "no_object"))]
Expr::Property(x) if _parent_chain_type == ChainType::Dotting => {
ChainArgument::Property((x.2).1)
}
Expr::Property(_) => unreachable!("unexpected Expr::Property for indexing"),
#[cfg(not(feature = "no_object"))]
Expr::FnCall(x, _)
if _parent_chain_type == ChainType::Dotting && !x.is_qualified() =>
{
let crate::ast::FnCallExpr {
args, constants, ..
} = x.as_ref();
let mut arg_values = StaticVec::with_capacity(args.len());
let mut first_arg_pos = Position::NONE;
for index in 0..args.len() {
let (value, pos) = self.get_arg_value(
scope, mods, state, lib, this_ptr, level, args, constants, index,
)?;
arg_values.push(value.flatten());
if index == 0 {
first_arg_pos = pos;
}
}
(arg_values, first_arg_pos).into()
}
#[cfg(not(feature = "no_object"))]
Expr::FnCall(_, _) if _parent_chain_type == ChainType::Dotting => {
unreachable!("function call in dot chain should not be namespace-qualified")
}
#[cfg(not(feature = "no_object"))]
expr if _parent_chain_type == ChainType::Dotting => {
unreachable!("invalid dot expression: {:?}", expr);
}
#[cfg(not(feature = "no_index"))]
_ if _parent_chain_type == ChainType::Indexing => self
.eval_expr(scope, mods, state, lib, this_ptr, lhs, level)
.map(|v| (v.flatten(), lhs.position()).into())?,
expr => unreachable!("unknown chained expression: {:?}", expr),
};
// Push in reverse order
let chain_type = match_chaining_type(expr);
self.eval_dot_index_chain_arguments(
scope, mods, state, lib, this_ptr, rhs, *term, chain_type, idx_values, size,
level,
)?;
idx_values.push(lhs_val);
}
#[cfg(not(feature = "no_object"))]
_ if _parent_chain_type == ChainType::Dotting => {
unreachable!("invalid dot expression: {:?}", expr);
}
#[cfg(not(feature = "no_index"))]
_ if _parent_chain_type == ChainType::Indexing => idx_values.push(
self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)
.map(|v| (v.flatten(), expr.position()).into())?,
),
_ => unreachable!("unknown chained expression: {:?}", expr),
}
Ok(())
}
/// Get the value at the indexed position of a base type.
/// [`Position`] in [`EvalAltResult`] may be [`NONE`][Position::NONE] and should be set afterwards.
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
fn get_indexed_mut<'t>(
&self,
mods: &mut Imports,
state: &mut EvalState,
lib: &[&Module],
target: &'t mut Dynamic,
idx: Dynamic,
idx_pos: Position,
add_if_not_found: bool,
use_indexers: bool,
level: usize,
) -> Result<Target<'t>, Box<EvalAltResult>> {
#[cfg(not(feature = "unchecked"))]
self.inc_operations(state, Position::NONE)?;
let mut idx = idx;
let _add_if_not_found = add_if_not_found;
match target {
#[cfg(not(feature = "no_index"))]
Dynamic(Union::Array(arr, _, _)) => {
// val_array[idx]
let index = idx
.as_int()
.map_err(|typ| self.make_type_mismatch_err::<crate::INT>(typ, idx_pos))?;
let arr_len = arr.len();
#[cfg(not(feature = "unchecked"))]
let arr_idx = if index < 0 {
// Count from end if negative
arr_len
- index
.checked_abs()
.ok_or_else(|| {
Box::new(EvalAltResult::ErrorArrayBounds(arr_len, index, idx_pos))
})
.and_then(|n| {
if n as usize > arr_len {
Err(EvalAltResult::ErrorArrayBounds(arr_len, index, idx_pos)
.into())
} else {
Ok(n as usize)
}
})?
} else {
index as usize
};
#[cfg(feature = "unchecked")]
let arr_idx = if index < 0 {
// Count from end if negative
arr_len - index.abs() as usize
} else {
index as usize
};
arr.get_mut(arr_idx)
.map(Target::from)
.ok_or_else(|| EvalAltResult::ErrorArrayBounds(arr_len, index, idx_pos).into())
}
#[cfg(not(feature = "no_object"))]
Dynamic(Union::Map(map, _, _)) => {
// val_map[idx]
let index = idx.read_lock::<ImmutableString>().ok_or_else(|| {
self.make_type_mismatch_err::<ImmutableString>(idx.type_name(), idx_pos)
})?;
if _add_if_not_found && !map.contains_key(index.as_str()) {
map.insert(index.clone().into(), Default::default());
}
Ok(map
.get_mut(index.as_str())
.map(Target::from)
.unwrap_or_else(|| Target::from(Dynamic::UNIT)))
}
#[cfg(not(feature = "no_index"))]
Dynamic(Union::Int(value, _, _)) => {
// val_int[idx]
let index = idx
.as_int()
.map_err(|typ| self.make_type_mismatch_err::<crate::INT>(typ, idx_pos))?;
let bits = std::mem::size_of_val(value) * 8;
let (bit_value, offset) = if index >= 0 {
let offset = index as usize;
(
if offset >= bits {
return EvalAltResult::ErrorBitFieldBounds(bits, index, idx_pos).into();
} else {
(*value & (1 << offset)) != 0
},
offset,
)
} else if let Some(abs_index) = index.checked_abs() {
let offset = abs_index as usize;
(
// Count from end if negative
if offset > bits {
return EvalAltResult::ErrorBitFieldBounds(bits, index, idx_pos).into();
} else {
(*value & (1 << (bits - offset))) != 0
},
offset,
)
} else {
return EvalAltResult::ErrorBitFieldBounds(bits, index, idx_pos).into();
};
Ok(Target::BitField(target, offset, bit_value.into()))
}
#[cfg(not(feature = "no_index"))]
Dynamic(Union::Str(s, _, _)) => {
// val_string[idx]
let index = idx
.as_int()
.map_err(|typ| self.make_type_mismatch_err::<crate::INT>(typ, idx_pos))?;
let (ch, offset) = if index >= 0 {
let offset = index as usize;
(
s.chars().nth(offset).ok_or_else(|| {
let chars_len = s.chars().count();
EvalAltResult::ErrorStringBounds(chars_len, index, idx_pos)
})?,
offset,
)
} else if let Some(abs_index) = index.checked_abs() {
let offset = abs_index as usize;
(
// Count from end if negative
s.chars().rev().nth(offset - 1).ok_or_else(|| {
let chars_len = s.chars().count();
EvalAltResult::ErrorStringBounds(chars_len, index, idx_pos)
})?,
offset,
)
} else {
let chars_len = s.chars().count();
return EvalAltResult::ErrorStringBounds(chars_len, index, idx_pos).into();
};
Ok(Target::StringChar(target, offset, ch.into()))
}
_ if use_indexers => {
let args = &mut [target, &mut idx];
let hash_get = FnCallHashes::from_native(crate::calc_fn_hash(FN_IDX_GET, 2));
let idx_pos = Position::NONE;
self.exec_fn_call(
mods, state, lib, FN_IDX_GET, hash_get, args, true, true, idx_pos, None, level,
)
.map(|(v, _)| v.into())
}
_ => EvalAltResult::ErrorIndexingType(
format!(
"{} [{}]",
self.map_type_name(target.type_name()),
self.map_type_name(idx.type_name())
),
Position::NONE,
)
.into(),
}
}
/// Evaluate an expression.
pub(crate) fn eval_expr(
&self,
scope: &mut Scope,
mods: &mut Imports,
state: &mut EvalState,
lib: &[&Module],
this_ptr: &mut Option<&mut Dynamic>,
expr: &Expr,
level: usize,
) -> RhaiResult {
#[cfg(not(feature = "unchecked"))]
self.inc_operations(state, expr.position())?;
let result = match expr {
Expr::DynamicConstant(x, _) => Ok(x.as_ref().clone()),
Expr::IntegerConstant(x, _) => Ok((*x).into()),
#[cfg(not(feature = "no_float"))]
Expr::FloatConstant(x, _) => Ok((*x).into()),
Expr::StringConstant(x, _) => Ok(x.clone().into()),
Expr::CharConstant(x, _) => Ok((*x).into()),
Expr::Variable(None, var_pos, x) if x.0.is_none() && x.2 == KEYWORD_THIS => this_ptr
.as_deref()
.cloned()
.ok_or_else(|| EvalAltResult::ErrorUnboundThis(*var_pos).into()),
Expr::Variable(_, _, _) => self
.search_namespace(scope, mods, state, lib, this_ptr, expr)
.map(|(val, _)| val.take_or_clone()),
// Statement block
Expr::Stmt(x) if x.is_empty() => Ok(Dynamic::UNIT),
Expr::Stmt(x) => {
self.eval_stmt_block(scope, mods, state, lib, this_ptr, x, true, level)
}
// lhs[idx_expr]
#[cfg(not(feature = "no_index"))]
Expr::Index(_, _, _) => {
self.eval_dot_index_chain(scope, mods, state, lib, this_ptr, expr, level, None)
}
// lhs.dot_rhs
#[cfg(not(feature = "no_object"))]
Expr::Dot(_, _, _) => {
self.eval_dot_index_chain(scope, mods, state, lib, this_ptr, expr, level, None)
}
// `... ${...} ...`
Expr::InterpolatedString(x, pos) => {
let mut pos = *pos;
let mut result: Dynamic = self.empty_string.clone().into();
for expr in x.iter() {
let item = self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?;
self.eval_op_assignment(
mods,
state,
lib,
Some(OpAssignment::new(TOKEN_OP_CONCAT)),
pos,
&mut (&mut result).into(),
("", Position::NONE),
item,
)
.map_err(|err| err.fill_position(expr.position()))?;
pos = expr.position();
self.check_data_size(&result)
.map_err(|err| err.fill_position(pos))?;
}
assert!(
result.is::<ImmutableString>(),
"interpolated string must be a string"
);
Ok(result)
}
#[cfg(not(feature = "no_index"))]
Expr::Array(x, _) => {
let mut arr = Array::with_capacity(x.len());
for item in x.as_ref() {
arr.push(
self.eval_expr(scope, mods, state, lib, this_ptr, item, level)?
.flatten(),
);
}
Ok(arr.into())
}
#[cfg(not(feature = "no_object"))]
Expr::Map(x, _) => {
let mut map = x.1.clone();
for (Ident { name: key, .. }, expr) in &x.0 {
let value_ref = map
.get_mut(key.as_str())
.expect("never fails because the template should contain all the keys");
*value_ref = self
.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.flatten();
}
Ok(map.into())
}
// Namespace-qualified function call
Expr::FnCall(x, pos) if x.is_qualified() => {
let FnCallExpr {
name,
namespace,
hashes,
args,
constants,
..
} = x.as_ref();
let namespace = namespace
.as_ref()
.expect("never fails because function call is qualified");
let hash = hashes.native;
self.make_qualified_function_call(
scope, mods, state, lib, this_ptr, namespace, name, args, constants, hash,
*pos, level,
)
}
// Normal function call
Expr::FnCall(x, pos) => {
let FnCallExpr {
name,
capture,
hashes,
args,
constants,
..
} = x.as_ref();
self.make_function_call(
scope, mods, state, lib, this_ptr, name, args, constants, *hashes, *pos,
*capture, level,
)
}
Expr::And(x, _) => {
Ok((self
.eval_expr(scope, mods, state, lib, this_ptr, &x.lhs, level)?
.as_bool()
.map_err(|typ| self.make_type_mismatch_err::<bool>(typ, x.lhs.position()))?
&& // Short-circuit using &&
self
.eval_expr(scope, mods, state, lib, this_ptr, &x.rhs, level)?
.as_bool()
.map_err(|typ| self.make_type_mismatch_err::<bool>(typ, x.rhs.position()))?)
.into())
}
Expr::Or(x, _) => {
Ok((self
.eval_expr(scope, mods, state, lib, this_ptr, &x.lhs, level)?
.as_bool()
.map_err(|typ| self.make_type_mismatch_err::<bool>(typ, x.lhs.position()))?
|| // Short-circuit using ||
self
.eval_expr(scope, mods, state, lib, this_ptr, &x.rhs, level)?
.as_bool()
.map_err(|typ| self.make_type_mismatch_err::<bool>(typ, x.rhs.position()))?)
.into())
}
Expr::BoolConstant(x, _) => Ok((*x).into()),
Expr::Unit(_) => Ok(Dynamic::UNIT),
Expr::Custom(custom, _) => {
let expressions: StaticVec<_> = custom.keywords.iter().map(Into::into).collect();
let key_token = custom.tokens.first().expect(
"never fails because a custom syntax stream must contain at least one token",
);
let custom_def = self
.custom_syntax.get(key_token)
.expect("never fails because the custom syntax leading token should match with definition");
let mut context = EvalContext {
engine: self,
scope,
mods,
state,
lib,
this_ptr,
level,
};
(custom_def.func)(&mut context, &expressions)
}
_ => unreachable!("expression cannot be evaluated: {:?}", expr),
};
self.check_return_value(result)
.map_err(|err| err.fill_position(expr.position()))
}
/// Evaluate a statements block.
pub(crate) fn eval_stmt_block(
&self,
scope: &mut Scope,
mods: &mut Imports,
state: &mut EvalState,
lib: &[&Module],
this_ptr: &mut Option<&mut Dynamic>,
statements: &[Stmt],
restore_prev_state: bool,
level: usize,
) -> RhaiResult {
if statements.is_empty() {
return Ok(Dynamic::UNIT);
}
let mut _extra_fn_resolution_cache = false;
let prev_always_search_scope = state.always_search_scope;
let prev_scope_len = scope.len();
let prev_mods_len = mods.len();
if restore_prev_state {
state.scope_level += 1;
}
let result = statements.iter().try_fold(Dynamic::UNIT, |_, stmt| {
let _mods_len = mods.len();
let r = self.eval_stmt(scope, mods, state, lib, this_ptr, stmt, level)?;
#[cfg(not(feature = "no_module"))]
if matches!(stmt, Stmt::Import(_, _, _)) {
// Get the extra modules - see if any functions are marked global.
// Without global functions, the extra modules never affect function resolution.
if mods
.scan_raw()
.skip(_mods_len)
.any(|(_, m)| m.contains_indexed_global_functions())
{
if _extra_fn_resolution_cache {
// When new module is imported with global functions and there is already
// a new cache, clear it - notice that this is expensive as all function
// resolutions must start again
state.fn_resolution_cache_mut().clear();
} else if restore_prev_state {
// When new module is imported with global functions, push a new cache
state.push_fn_resolution_cache();
_extra_fn_resolution_cache = true;
} else {
// When the block is to be evaluated in-place, just clear the current cache
state.fn_resolution_cache_mut().clear();
}
}
}
Ok(r)
});
if _extra_fn_resolution_cache {
// If imports list is modified, pop the functions lookup cache
state.pop_fn_resolution_cache();
}
if restore_prev_state {
scope.rewind(prev_scope_len);
mods.truncate(prev_mods_len);
state.scope_level -= 1;
// The impact of new local variables goes away at the end of a block
// because any new variables introduced will go out of scope
state.always_search_scope = prev_always_search_scope;
}
result
}
/// Evaluate an op-assignment statement.
/// [`Position`] in [`EvalAltResult`] is [`NONE`][Position::NONE] and should be set afterwards.
pub(crate) fn eval_op_assignment(
&self,
mods: &mut Imports,
state: &mut EvalState,
lib: &[&Module],
op_info: Option<OpAssignment>,
op_pos: Position,
target: &mut Target,
root: (&str, Position),
new_val: Dynamic,
) -> Result<(), Box<EvalAltResult>> {
if target.is_read_only() {
// Assignment to constant variable
return EvalAltResult::ErrorAssignmentToConstant(root.0.to_string(), root.1).into();
}
let mut new_val = new_val;
if let Some(OpAssignment {
hash_op_assign,
hash_op,
op,
}) = op_info
{
{
let mut lock_guard;
let lhs_ptr_inner;
#[cfg(not(feature = "no_closure"))]
let target_is_shared = target.is_shared();
#[cfg(feature = "no_closure")]
let target_is_shared = false;
if target_is_shared {
lock_guard = target
.write_lock::<Dynamic>()
.expect("never fails when casting to `Dynamic`");
lhs_ptr_inner = &mut *lock_guard;
} else {
lhs_ptr_inner = &mut *target;
}
let hash = hash_op_assign;
let args = &mut [lhs_ptr_inner, &mut new_val];
match self.call_native_fn(mods, state, lib, op, hash, args, true, true, op_pos) {
Err(err) if matches!(err.as_ref(), EvalAltResult::ErrorFunctionNotFound(f, _) if f.starts_with(op)) =>
{
// Expand to `var = var op rhs`
let op = &op[..op.len() - 1]; // extract operator without =
// Run function
let (value, _) = self.call_native_fn(
mods, state, lib, op, hash_op, args, true, false, op_pos,
)?;
*args[0] = value.flatten();
}
err => return err.map(|_| ()),
}
}
} else {
// Normal assignment
*target.as_mut() = new_val;
}
target.propagate_changed_value()
}
/// Evaluate a statement.
///
/// # Safety
///
/// This method uses some unsafe code, mainly for avoiding cloning of local variable names via
/// direct lifetime casting.
pub(crate) fn eval_stmt(
&self,
scope: &mut Scope,
mods: &mut Imports,
state: &mut EvalState,
lib: &[&Module],
this_ptr: &mut Option<&mut Dynamic>,
stmt: &Stmt,
level: usize,
) -> RhaiResult {
#[cfg(not(feature = "unchecked"))]
self.inc_operations(state, stmt.position())?;
let result = match stmt {
// No-op
Stmt::Noop(_) => Ok(Dynamic::UNIT),
// Expression as statement
Stmt::Expr(expr) => Ok(self
.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.flatten()),
// var op= rhs
Stmt::Assignment(x, op_pos) if x.0.is_variable_access(false) => {
let (lhs_expr, op_info, rhs_expr) = x.as_ref();
let rhs_val = self
.eval_expr(scope, mods, state, lib, this_ptr, rhs_expr, level)?
.flatten();
let (mut lhs_ptr, pos) =
self.search_namespace(scope, mods, state, lib, this_ptr, lhs_expr)?;
let var_name = lhs_expr
.get_variable_name(false)
.expect("never fails because `lhs_ptr` is a `Variable`s");
if !lhs_ptr.is_ref() {
return EvalAltResult::ErrorAssignmentToConstant(var_name.to_string(), pos)
.into();
}
#[cfg(not(feature = "unchecked"))]
self.inc_operations(state, pos)?;
self.eval_op_assignment(
mods,
state,
lib,
*op_info,
*op_pos,
&mut lhs_ptr,
(var_name, pos),
rhs_val,
)
.map_err(|err| err.fill_position(rhs_expr.position()))?;
if op_info.is_some() {
self.check_data_size(lhs_ptr.as_ref())
.map_err(|err| err.fill_position(lhs_expr.position()))?;
}
Ok(Dynamic::UNIT)
}
// lhs op= rhs
Stmt::Assignment(x, op_pos) => {
let (lhs_expr, op_info, rhs_expr) = x.as_ref();
let rhs_val = self
.eval_expr(scope, mods, state, lib, this_ptr, rhs_expr, level)?
.flatten();
let _new_val = Some(((rhs_val, rhs_expr.position()), (*op_info, *op_pos)));
// Must be either `var[index] op= val` or `var.prop op= val`
match lhs_expr {
// name op= rhs (handled above)
Expr::Variable(_, _, _) => {
unreachable!("Expr::Variable case should already been handled")
}
// idx_lhs[idx_expr] op= rhs
#[cfg(not(feature = "no_index"))]
Expr::Index(_, _, _) => {
self.eval_dot_index_chain(
scope, mods, state, lib, this_ptr, lhs_expr, level, _new_val,
)?;
Ok(Dynamic::UNIT)
}
// dot_lhs.dot_rhs op= rhs
#[cfg(not(feature = "no_object"))]
Expr::Dot(_, _, _) => {
self.eval_dot_index_chain(
scope, mods, state, lib, this_ptr, lhs_expr, level, _new_val,
)?;
Ok(Dynamic::UNIT)
}
_ => unreachable!("cannot assign to expression: {:?}", lhs_expr),
}
}
// Block scope
Stmt::Block(statements, _) if statements.is_empty() => Ok(Dynamic::UNIT),
Stmt::Block(statements, _) => {
self.eval_stmt_block(scope, mods, state, lib, this_ptr, statements, true, level)
}
// If statement
Stmt::If(expr, x, _) => {
let guard_val = self
.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.as_bool()
.map_err(|typ| self.make_type_mismatch_err::<bool>(typ, expr.position()))?;
if guard_val {
if !x.0.is_empty() {
self.eval_stmt_block(scope, mods, state, lib, this_ptr, &x.0, true, level)
} else {
Ok(Dynamic::UNIT)
}
} else {
if !x.1.is_empty() {
self.eval_stmt_block(scope, mods, state, lib, this_ptr, &x.1, true, level)
} else {
Ok(Dynamic::UNIT)
}
}
}
// Switch statement
Stmt::Switch(match_expr, x, _) => {
let (table, def_stmt) = x.as_ref();
let value = self.eval_expr(scope, mods, state, lib, this_ptr, match_expr, level)?;
if value.is_hashable() {
let hasher = &mut get_hasher();
value.hash(hasher);
let hash = hasher.finish();
table.get(&hash).and_then(|t| {
if let Some(condition) = &t.0 {
match self
.eval_expr(scope, mods, state, lib, this_ptr, &condition, level)
.and_then(|v| {
v.as_bool().map_err(|typ| {
self.make_type_mismatch_err::<bool>(
typ,
condition.position(),
)
})
}) {
Ok(true) => (),
Ok(false) => return None,
Err(err) => return Some(Err(err)),
}
}
let statements = &t.1;
Some(if !statements.is_empty() {
self.eval_stmt_block(
scope, mods, state, lib, this_ptr, statements, true, level,
)
} else {
Ok(Dynamic::UNIT)
})
})
} else {
// Non-hashable values never match any specific clause
None
}
.unwrap_or_else(|| {
// Default match clause
if !def_stmt.is_empty() {
self.eval_stmt_block(
scope, mods, state, lib, this_ptr, def_stmt, true, level,
)
} else {
Ok(Dynamic::UNIT)
}
})
}
// Loop
Stmt::While(Expr::Unit(_), body, _) => loop {
if !body.is_empty() {
match self.eval_stmt_block(scope, mods, state, lib, this_ptr, body, true, level)
{
Ok(_) => (),
Err(err) => match *err {
EvalAltResult::LoopBreak(false, _) => (),
EvalAltResult::LoopBreak(true, _) => return Ok(Dynamic::UNIT),
_ => return Err(err),
},
}
} else {
#[cfg(not(feature = "unchecked"))]
self.inc_operations(state, body.position())?;
}
},
// While loop
Stmt::While(expr, body, _) => loop {
let condition = self
.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.as_bool()
.map_err(|typ| self.make_type_mismatch_err::<bool>(typ, expr.position()))?;
if !condition {
return Ok(Dynamic::UNIT);
}
if !body.is_empty() {
match self.eval_stmt_block(scope, mods, state, lib, this_ptr, body, true, level)
{
Ok(_) => (),
Err(err) => match *err {
EvalAltResult::LoopBreak(false, _) => (),
EvalAltResult::LoopBreak(true, _) => return Ok(Dynamic::UNIT),
_ => return Err(err),
},
}
}
},
// Do loop
Stmt::Do(body, expr, options, _) => loop {
let is_while = !options.contains(AST_OPTION_NEGATED);
if !body.is_empty() {
match self.eval_stmt_block(scope, mods, state, lib, this_ptr, body, true, level)
{
Ok(_) => (),
Err(err) => match *err {
EvalAltResult::LoopBreak(false, _) => continue,
EvalAltResult::LoopBreak(true, _) => return Ok(Dynamic::UNIT),
_ => return Err(err),
},
}
}
let condition = self
.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.as_bool()
.map_err(|typ| self.make_type_mismatch_err::<bool>(typ, expr.position()))?;
if condition ^ is_while {
return Ok(Dynamic::UNIT);
}
},
// For loop
Stmt::For(expr, x, _) => {
let (Ident { name, .. }, counter, statements) = x.as_ref();
let iter_obj = self
.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.flatten();
let iter_type = iter_obj.type_id();
// lib should only contain scripts, so technically they cannot have iterators
// Search order:
// 1) Global namespace - functions registered via Engine::register_XXX
// 2) Global modules - packages
// 3) Imported modules - functions marked with global namespace
// 4) Global sub-modules - functions marked with global namespace
let func = self
.global_namespace
.get_iter(iter_type)
.or_else(|| {
self.global_modules
.iter()
.find_map(|m| m.get_iter(iter_type))
})
.or_else(|| mods.get_iter(iter_type))
.or_else(|| {
self.global_sub_modules
.values()
.find_map(|m| m.get_qualified_iter(iter_type))
});
if let Some(func) = func {
// Add the loop variables
let orig_scope_len = scope.len();
let counter_index = if let Some(Ident { name, .. }) = counter {
scope.push(unsafe_cast_var_name_to_lifetime(name), 0 as INT);
Some(scope.len() - 1)
} else {
None
};
scope.push(unsafe_cast_var_name_to_lifetime(name), ());
let index = scope.len() - 1;
state.scope_level += 1;
for (x, iter_value) in func(iter_obj).enumerate() {
// Increment counter
if let Some(c) = counter_index {
#[cfg(not(feature = "unchecked"))]
if x > INT::MAX as usize {
return EvalAltResult::ErrorArithmetic(
format!("for-loop counter overflow: {}", x),
counter
.as_ref()
.expect("never fails because `counter` is `Some`")
.pos,
)
.into();
}
let mut counter_var = scope
.get_mut_by_index(c)
.write_lock::<INT>()
.expect("never fails because the counter always holds an `INT`");
*counter_var = x as INT;
}
let loop_var = scope.get_mut_by_index(index);
let value = iter_value.flatten();
#[cfg(not(feature = "no_closure"))]
let loop_var_is_shared = loop_var.is_shared();
#[cfg(feature = "no_closure")]
let loop_var_is_shared = false;
if loop_var_is_shared {
let mut value_ref = loop_var
.write_lock()
.expect("never fails when casting to `Dynamic`");
*value_ref = value;
} else {
*loop_var = value;
}
#[cfg(not(feature = "unchecked"))]
self.inc_operations(state, statements.position())?;
if statements.is_empty() {
continue;
}
let result = self.eval_stmt_block(
scope, mods, state, lib, this_ptr, statements, true, level,
);
match result {
Ok(_) => (),
Err(err) => match *err {
EvalAltResult::LoopBreak(false, _) => (),
EvalAltResult::LoopBreak(true, _) => break,
_ => return Err(err),
},
}
}
state.scope_level -= 1;
scope.rewind(orig_scope_len);
Ok(Dynamic::UNIT)
} else {
EvalAltResult::ErrorFor(expr.position()).into()
}
}
// Continue statement
Stmt::Continue(pos) => EvalAltResult::LoopBreak(false, *pos).into(),
// Break statement
Stmt::Break(pos) => EvalAltResult::LoopBreak(true, *pos).into(),
// Namespace-qualified function call
Stmt::FnCall(x, pos) if x.is_qualified() => {
let FnCallExpr {
name,
namespace,
hashes,
args,
constants,
..
} = x.as_ref();
let namespace = namespace
.as_ref()
.expect("never fails because function call is qualified");
let hash = hashes.native;
self.make_qualified_function_call(
scope, mods, state, lib, this_ptr, namespace, name, args, constants, hash,
*pos, level,
)
}
// Normal function call
Stmt::FnCall(x, pos) => {
let FnCallExpr {
name,
capture,
hashes,
args,
constants,
..
} = x.as_ref();
self.make_function_call(
scope, mods, state, lib, this_ptr, name, args, constants, *hashes, *pos,
*capture, level,
)
}
// Try/Catch statement
Stmt::TryCatch(x, _) => {
let (try_stmt, err_var, catch_stmt) = x.as_ref();
let result = self
.eval_stmt_block(scope, mods, state, lib, this_ptr, try_stmt, true, level)
.map(|_| Dynamic::UNIT);
match result {
Ok(_) => result,
Err(err) if err.is_pseudo_error() => Err(err),
Err(err) if !err.is_catchable() => Err(err),
Err(mut err) => {
let err_value = match *err {
EvalAltResult::ErrorRuntime(ref x, _) => x.clone(),
#[cfg(feature = "no_object")]
_ => {
err.take_position();
err.to_string().into()
}
#[cfg(not(feature = "no_object"))]
_ => {
let mut err_map: Map = Default::default();
let err_pos = err.take_position();
err_map.insert("message".into(), err.to_string().into());
if let Some(ref source) = state.source {
err_map.insert("source".into(), source.as_str().into());
}
if err_pos.is_none() {
// No position info
} else {
let line = err_pos.line().expect("never fails because a non-NONE `Position` always has a line number") as INT;
let position = if err_pos.is_beginning_of_line() {
0
} else {
err_pos.position().expect("never fails because a non-NONE `Position` always has a character position")
} as INT;
err_map.insert("line".into(), line.into());
err_map.insert("position".into(), position.into());
}
err.dump_fields(&mut err_map);
err_map.into()
}
};
let orig_scope_len = scope.len();
state.scope_level += 1;
err_var.as_ref().map(|Ident { name, .. }| {
scope.push(unsafe_cast_var_name_to_lifetime(name), err_value)
});
let result = self.eval_stmt_block(
scope, mods, state, lib, this_ptr, catch_stmt, true, level,
);
state.scope_level -= 1;
scope.rewind(orig_scope_len);
match result {
Ok(_) => Ok(Dynamic::UNIT),
Err(result_err) => match *result_err {
// Re-throw exception
EvalAltResult::ErrorRuntime(Dynamic(Union::Unit(_, _, _)), pos) => {
err.set_position(pos);
Err(err)
}
_ => Err(result_err),
},
}
}
}
}
// Return value
Stmt::Return(ReturnType::Return, Some(expr), pos) => EvalAltResult::Return(
self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.flatten(),
*pos,
)
.into(),
// Empty return
Stmt::Return(ReturnType::Return, None, pos) => {
EvalAltResult::Return(Dynamic::UNIT, *pos).into()
}
// Throw value
Stmt::Return(ReturnType::Exception, Some(expr), pos) => EvalAltResult::ErrorRuntime(
self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.flatten(),
*pos,
)
.into(),
// Empty throw
Stmt::Return(ReturnType::Exception, None, pos) => {
EvalAltResult::ErrorRuntime(Dynamic::UNIT, *pos).into()
}
// Let/const statement
Stmt::Var(expr, x, options, _) => {
let name = &x.name;
let entry_type = if options.contains(AST_OPTION_CONSTANT) {
AccessMode::ReadOnly
} else {
AccessMode::ReadWrite
};
let export = options.contains(AST_OPTION_EXPORTED);
let value = self
.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.flatten();
let (var_name, _alias): (Cow<'_, str>, _) = if state.is_global() {
#[cfg(not(feature = "no_function"))]
if entry_type == AccessMode::ReadOnly && lib.iter().any(|&m| !m.is_empty()) {
let global = if let Some(index) = mods.find(KEYWORD_GLOBAL) {
match mods
.get_mut(index)
.expect("never fails because the index came from `find`")
{
m if m.internal => Some(m),
_ => None,
}
} else {
// Create automatic global module
let mut global = Module::new();
global.internal = true;
mods.push(KEYWORD_GLOBAL, global);
Some(
mods.get_mut(mods.len() - 1)
.expect("never fails because the global module was just added"),
)
};
if let Some(global) = global {
Shared::get_mut(global)
.expect("never fails because the global module is never shared")
.set_var(name.clone(), value.clone());
}
}
(
name.to_string().into(),
if export { Some(name.clone()) } else { None },
)
} else if export {
unreachable!("exported variable not on global level");
} else {
(unsafe_cast_var_name_to_lifetime(name).into(), None)
};
scope.push_dynamic_value(var_name, entry_type, value);
#[cfg(not(feature = "no_module"))]
_alias.map(|alias| scope.add_entry_alias(scope.len() - 1, alias));
Ok(Dynamic::UNIT)
}
// Import statement
#[cfg(not(feature = "no_module"))]
Stmt::Import(expr, export, _pos) => {
// Guard against too many modules
#[cfg(not(feature = "unchecked"))]
if state.num_modules >= self.max_modules() {
return EvalAltResult::ErrorTooManyModules(*_pos).into();
}
if let Some(path) = self
.eval_expr(scope, mods, state, lib, this_ptr, &expr, level)?
.try_cast::<ImmutableString>()
{
use crate::ModuleResolver;
let source = state.source.as_ref().map(|s| s.as_str());
let path_pos = expr.position();
let module = state
.embedded_module_resolver
.as_ref()
.and_then(|r| match r.resolve(self, source, &path, path_pos) {
Err(err)
if matches!(*err, EvalAltResult::ErrorModuleNotFound(_, _)) =>
{
None
}
result => Some(result),
})
.or_else(|| {
self.module_resolver
.as_ref()
.map(|r| r.resolve(self, source, &path, path_pos))
})
.unwrap_or_else(|| {
EvalAltResult::ErrorModuleNotFound(path.to_string(), path_pos).into()
})?;
if let Some(name) = export.as_ref().map(|x| x.name.clone()) {
if !module.is_indexed() {
// Index the module (making a clone copy if necessary) if it is not indexed
let mut module = crate::fn_native::shared_take_or_clone(module);
module.build_index();
mods.push(name, module);
} else {
mods.push(name, module);
}
}
state.num_modules += 1;
Ok(Dynamic::UNIT)
} else {
Err(self.make_type_mismatch_err::<ImmutableString>("", expr.position()))
}
}
// Export statement
#[cfg(not(feature = "no_module"))]
Stmt::Export(list, _) => {
for (Ident { name, pos, .. }, Ident { name: rename, .. }) in list.as_ref() {
// Mark scope variables as public
if let Some((index, _)) = scope.get_index(name) {
scope.add_entry_alias(
index,
if rename.is_empty() { name } else { rename }.clone(),
);
} else {
return EvalAltResult::ErrorVariableNotFound(name.to_string(), *pos).into();
}
}
Ok(Dynamic::UNIT)
}
// Share statement
#[cfg(not(feature = "no_closure"))]
Stmt::Share(name) => {
if let Some((index, _)) = scope.get_index(name) {
let val = scope.get_mut_by_index(index);
if !val.is_shared() {
// Replace the variable with a shared value.
*val = std::mem::take(val).into_shared();
}
}
Ok(Dynamic::UNIT)
}
};
self.check_return_value(result)
.map_err(|err| err.fill_position(stmt.position()))
}
/// Check a result to ensure that the data size is within allowable limit.
#[cfg(feature = "unchecked")]
#[inline(always)]
fn check_return_value(&self, result: RhaiResult) -> RhaiResult {
result
}
/// Check a result to ensure that the data size is within allowable limit.
#[cfg(not(feature = "unchecked"))]
#[inline(always)]
fn check_return_value(&self, result: RhaiResult) -> RhaiResult {
result.and_then(|r| self.check_data_size(&r).map(|_| r))
}
#[cfg(feature = "unchecked")]
#[inline(always)]
fn check_data_size(&self, _value: &Dynamic) -> Result<(), Box<EvalAltResult>> {
Ok(())
}
#[cfg(not(feature = "unchecked"))]
fn check_data_size(&self, value: &Dynamic) -> Result<(), Box<EvalAltResult>> {
// Recursively calculate the size of a value (especially `Array` and `Map`)
fn calc_size(value: &Dynamic) -> (usize, usize, usize) {
match value.0 {
#[cfg(not(feature = "no_index"))]
Union::Array(ref arr, _, _) => {
arr.iter()
.fold((0, 0, 0), |(arrays, maps, strings), value| match value.0 {
Union::Array(_, _, _) => {
let (a, m, s) = calc_size(value);
(arrays + a + 1, maps + m, strings + s)
}
#[cfg(not(feature = "no_object"))]
Union::Map(_, _, _) => {
let (a, m, s) = calc_size(value);
(arrays + a + 1, maps + m, strings + s)
}
Union::Str(ref s, _, _) => (arrays + 1, maps, strings + s.len()),
_ => (arrays + 1, maps, strings),
})
}
#[cfg(not(feature = "no_object"))]
Union::Map(ref map, _, _) => {
map.values()
.fold((0, 0, 0), |(arrays, maps, strings), value| match value.0 {
#[cfg(not(feature = "no_index"))]
Union::Array(_, _, _) => {
let (a, m, s) = calc_size(value);
(arrays + a, maps + m + 1, strings + s)
}
Union::Map(_, _, _) => {
let (a, m, s) = calc_size(value);
(arrays + a, maps + m + 1, strings + s)
}
Union::Str(ref s, _, _) => (arrays, maps + 1, strings + s.len()),
_ => (arrays, maps + 1, strings),
})
}
Union::Str(ref s, _, _) => (0, 0, s.len()),
_ => (0, 0, 0),
}
}
// If no data size limits, just return
let mut _has_limit = self.limits.max_string_size.is_some();
#[cfg(not(feature = "no_index"))]
{
_has_limit = _has_limit || self.limits.max_array_size.is_some();
}
#[cfg(not(feature = "no_object"))]
{
_has_limit = _has_limit || self.limits.max_map_size.is_some();
}
if !_has_limit {
return Ok(());
}
let (_arr, _map, s) = calc_size(value);
if s > self
.limits
.max_string_size
.map_or(usize::MAX, NonZeroUsize::get)
{
return EvalAltResult::ErrorDataTooLarge(
"Length of string".to_string(),
Position::NONE,
)
.into();
}
#[cfg(not(feature = "no_index"))]
if _arr
> self
.limits
.max_array_size
.map_or(usize::MAX, NonZeroUsize::get)
{
return EvalAltResult::ErrorDataTooLarge("Size of array".to_string(), Position::NONE)
.into();
}
#[cfg(not(feature = "no_object"))]
if _map
> self
.limits
.max_map_size
.map_or(usize::MAX, NonZeroUsize::get)
{
return EvalAltResult::ErrorDataTooLarge(
"Size of object map".to_string(),
Position::NONE,
)
.into();
}
Ok(())
}
/// Check if the number of operations stay within limit.
#[cfg(not(feature = "unchecked"))]
pub(crate) fn inc_operations(
&self,
state: &mut EvalState,
pos: Position,
) -> Result<(), Box<EvalAltResult>> {
state.num_operations += 1;
// Guard against too many operations
if self.max_operations() > 0 && state.num_operations > self.max_operations() {
return EvalAltResult::ErrorTooManyOperations(pos).into();
}
// Report progress - only in steps
if let Some(ref progress) = self.progress {
if let Some(token) = progress(state.num_operations) {
// Terminate script if progress returns a termination token
return EvalAltResult::ErrorTerminated(token, pos).into();
}
}
Ok(())
}
/// Pretty-print a type name.
///
/// If a type is registered via [`register_type_with_name`][Engine::register_type_with_name],
/// the type name provided for the registration will be used.
#[inline(always)]
#[must_use]
pub fn map_type_name<'a>(&'a self, name: &'a str) -> &'a str {
self.type_names
.get(name)
.map(|s| s.as_str())
.unwrap_or_else(|| map_std_type_name(name))
}
/// Make a `Box<`[`EvalAltResult<ErrorMismatchDataType>`][EvalAltResult::ErrorMismatchDataType]`>`.
#[inline(always)]
#[must_use]
pub(crate) fn make_type_mismatch_err<T>(&self, typ: &str, pos: Position) -> Box<EvalAltResult> {
EvalAltResult::ErrorMismatchDataType(
self.map_type_name(type_name::<T>()).into(),
typ.into(),
pos,
)
.into()
}
}
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