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d83b829810
rhai/src/engine.rs
Stephen Chung d83b829810 Avoid copying arguments for function calls.
2020-05-03 16:54:24 +08:00

1513 lines
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//! Main module defining the script evaluation `Engine`.
use crate::any::{Dynamic, Union};
use crate::calc_fn_hash;
use crate::error::ParseErrorType;
use crate::optimize::OptimizationLevel;
use crate::packages::{CorePackage, Package, PackageLibrary, StandardPackage};
use crate::parser::{Expr, FnDef, ReturnType, Stmt};
use crate::result::EvalAltResult;
use crate::scope::{EntryType as ScopeEntryType, Scope};
use crate::token::Position;
use crate::stdlib::{
any::TypeId,
boxed::Box,
collections::HashMap,
format,
hash::{Hash, Hasher},
iter::once,
mem,
ops::{Deref, DerefMut},
rc::Rc,
string::{String, ToString},
sync::Arc,
vec::Vec,
};
#[cfg(not(feature = "no_std"))]
use crate::stdlib::collections::hash_map::DefaultHasher;
#[cfg(feature = "no_std")]
use ahash::AHasher;
/// An dynamic array of `Dynamic` values.
///
/// Not available under the `no_index` feature.
pub type Array = Vec<Dynamic>;
/// An dynamic hash map of `Dynamic` values with `String` keys.
///
/// Not available under the `no_object` feature.
pub type Map = HashMap<String, Dynamic>;
pub type FnCallArgs<'a> = [&'a mut Dynamic];
#[cfg(feature = "sync")]
pub type FnAny =
dyn Fn(&mut FnCallArgs, Position) -> Result<Dynamic, Box<EvalAltResult>> + Send + Sync;
#[cfg(not(feature = "sync"))]
pub type FnAny = dyn Fn(&mut FnCallArgs, Position) -> Result<Dynamic, Box<EvalAltResult>>;
#[cfg(feature = "sync")]
pub type IteratorFn = dyn Fn(Dynamic) -> Box<dyn Iterator<Item = Dynamic>> + Send + Sync;
#[cfg(not(feature = "sync"))]
pub type IteratorFn = dyn Fn(Dynamic) -> Box<dyn Iterator<Item = Dynamic>>;
#[cfg(debug_assertions)]
pub const MAX_CALL_STACK_DEPTH: usize = 28;
#[cfg(not(debug_assertions))]
pub const MAX_CALL_STACK_DEPTH: usize = 256;
#[cfg(not(feature = "only_i32"))]
#[cfg(not(feature = "only_i64"))]
const FUNCTIONS_COUNT: usize = 512;
#[cfg(any(feature = "only_i32", feature = "only_i64"))]
const FUNCTIONS_COUNT: usize = 256;
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 FUNC_TO_STRING: &str = "to_string";
pub const FUNC_GETTER: &str = "get$";
pub const FUNC_SETTER: &str = "set$";
/// A type that encapsulates a mutation target for an expression with side effects.
enum Target<'a> {
/// The target is a mutable reference to a `Dynamic` value somewhere.
Ref(&'a mut Dynamic),
/// The target is a temporary `Dynamic` value (i.e. the mutation can cause no side effects).
Value(Box<Dynamic>),
/// The target is a character inside a String.
/// This is necessary because directly pointing to a char inside a String is impossible.
StringChar(Box<(&'a mut Dynamic, usize, Dynamic)>),
}
impl Target<'_> {
/// Get the value of the `Target` as a `Dynamic`.
pub fn clone_into_dynamic(self) -> Dynamic {
match self {
Target::Ref(r) => r.clone(),
Target::Value(v) => *v,
Target::StringChar(s) => s.2,
}
}
/// Update the value of the `Target`.
pub fn set_value(&mut self, new_val: Dynamic, pos: Position) -> Result<(), Box<EvalAltResult>> {
match self {
Target::Ref(r) => **r = new_val,
Target::Value(_) => {
return Err(Box::new(EvalAltResult::ErrorAssignmentToUnknownLHS(pos)))
}
Target::StringChar(x) => match x.0 {
Dynamic(Union::Str(s)) => {
// Replace the character at the specified index position
let new_ch = new_val
.as_char()
.map_err(|_| EvalAltResult::ErrorCharMismatch(pos))?;
let mut chars: Vec<char> = s.chars().collect();
let ch = chars[x.1];
// See if changed - if so, update the String
if ch != new_ch {
chars[x.1] = new_ch;
s.clear();
chars.iter().for_each(|&ch| s.push(ch));
}
}
_ => panic!("should be String"),
},
}
Ok(())
}
}
impl<'a> From<&'a mut Dynamic> for Target<'a> {
fn from(value: &'a mut Dynamic) -> Self {
Self::Ref(value)
}
}
impl<T: Into<Dynamic>> From<T> for Target<'_> {
fn from(value: T) -> Self {
Self::Value(Box::new(value.into()))
}
}
/// A type to hold a number of `Dynamic` values in static storage for speed,
/// and any spill-overs in a `Vec`.
struct StaticVec<T: Default> {
/// Total number of values held.
len: usize,
/// Static storage. 4 slots should be enough for most cases - i.e. four levels of indirection.
list: [T; 4],
/// Dynamic storage. For spill-overs.
more: Vec<T>,
}
impl<T: Default> StaticVec<T> {
/// Create a new `StaticVec`.
pub fn new() -> Self {
Self {
len: 0,
list: [
Default::default(),
Default::default(),
Default::default(),
Default::default(),
],
more: Vec::new(),
}
}
/// Push a new value to the end of this `StaticVec`.
pub fn push<X: Into<T>>(&mut self, value: X) {
if self.len >= self.list.len() {
self.more.push(value.into());
} else {
self.list[self.len] = value.into();
}
self.len += 1;
}
/// Pop a value from the end of this `StaticVec`.
///
/// # Panics
///
/// Panics if the `StaticVec` is empty.
pub fn pop(&mut self) -> T {
let result = if self.len <= 0 {
panic!("nothing to pop!")
} else if self.len <= self.list.len() {
mem::replace(self.list.get_mut(self.len - 1).unwrap(), Default::default())
} else {
self.more.pop().unwrap()
};
self.len -= 1;
result
}
}
/// A type that holds all the current states of the Engine.
#[derive(Debug, Clone, Copy)]
pub struct State {
/// 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, subsequent offsets may become mis-aligned.
/// When that happens, this flag is turned on to force a scope lookup by name.
pub always_search: bool,
}
impl State {
/// Create a new `State`.
pub fn new() -> Self {
Self {
always_search: false,
}
}
}
/// A type that holds a library (`HashMap`) of script-defined functions.
///
/// Since script-defined functions have `Dynamic` parameters, functions with the same name
/// and number of parameters are considered equivalent.
///
/// The key of the `HashMap` is a `u64` hash calculated by the function `calc_fn_def`.
#[derive(Debug, Clone)]
pub struct FunctionsLib(
#[cfg(feature = "sync")] HashMap<u64, Arc<FnDef>>,
#[cfg(not(feature = "sync"))] HashMap<u64, Rc<FnDef>>,
);
impl FunctionsLib {
/// Create a new `FunctionsLib`.
pub fn new() -> Self {
FunctionsLib(HashMap::new())
}
/// Create a new `FunctionsLib` from a collection of `FnDef`.
pub fn from_vec(vec: Vec<FnDef>) -> Self {
FunctionsLib(
vec.into_iter()
.map(|f| {
let hash = calc_fn_def(&f.name, f.params.len());
#[cfg(feature = "sync")]
{
(hash, Arc::new(f))
}
#[cfg(not(feature = "sync"))]
{
(hash, Rc::new(f))
}
})
.collect(),
)
}
/// Does a certain function exist in the `FunctionsLib`?
pub fn has_function(&self, name: &str, params: usize) -> bool {
self.contains_key(&calc_fn_def(name, params))
}
/// Get a function definition from the `FunctionsLib`.
pub fn get_function(&self, name: &str, params: usize) -> Option<&FnDef> {
self.get(&calc_fn_def(name, params)).map(|f| f.as_ref())
}
/// Merge another `FunctionsLib` into this `FunctionsLib`.
pub fn merge(&self, other: &Self) -> Self {
if self.is_empty() {
other.clone()
} else if other.is_empty() {
self.clone()
} else {
let mut functions = self.clone();
functions.extend(other.iter().map(|(hash, fn_def)| (*hash, fn_def.clone())));
functions
}
}
}
impl Deref for FunctionsLib {
#[cfg(feature = "sync")]
type Target = HashMap<u64, Arc<FnDef>>;
#[cfg(not(feature = "sync"))]
type Target = HashMap<u64, Rc<FnDef>>;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl DerefMut for FunctionsLib {
#[cfg(feature = "sync")]
fn deref_mut(&mut self) -> &mut HashMap<u64, Arc<FnDef>> {
&mut self.0
}
#[cfg(not(feature = "sync"))]
fn deref_mut(&mut self) -> &mut HashMap<u64, Rc<FnDef>> {
&mut self.0
}
}
/// Rhai main scripting engine.
///
/// ```
/// # 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(())
/// # }
/// ```
///
/// Currently, `Engine` is neither `Send` nor `Sync`. Turn on the `sync` feature to make it `Send + Sync`.
pub struct Engine {
/// A collection of all library packages loaded into the engine.
pub(crate) packages: Vec<PackageLibrary>,
/// A `HashMap` containing all compiled functions known to the engine.
///
/// The key of the `HashMap` is a `u64` hash calculated by the function `crate::calc_fn_hash`.
pub(crate) functions: HashMap<u64, Box<FnAny>>,
/// A hashmap containing all iterators known to the engine.
pub(crate) type_iterators: HashMap<TypeId, Box<IteratorFn>>,
/// A hashmap mapping type names to pretty-print names.
pub(crate) type_names: HashMap<String, String>,
/// Closure for implementing the `print` command.
#[cfg(feature = "sync")]
pub(crate) print: Box<dyn Fn(&str) + Send + Sync + 'static>,
/// Closure for implementing the `print` command.
#[cfg(not(feature = "sync"))]
pub(crate) print: Box<dyn Fn(&str) + 'static>,
/// Closure for implementing the `debug` command.
#[cfg(feature = "sync")]
pub(crate) debug: Box<dyn Fn(&str) + Send + Sync + 'static>,
/// Closure for implementing the `debug` command.
#[cfg(not(feature = "sync"))]
pub(crate) debug: Box<dyn Fn(&str) + 'static>,
/// Optimize the AST after compilation.
pub(crate) optimization_level: OptimizationLevel,
/// Maximum levels of call-stack to prevent infinite recursion.
///
/// Defaults to 28 for debug builds and 256 for non-debug builds.
pub(crate) max_call_stack_depth: usize,
}
impl Default for Engine {
fn default() -> Self {
// Create the new scripting Engine
let mut engine = Self {
packages: Vec::new(),
functions: HashMap::with_capacity(FUNCTIONS_COUNT),
type_iterators: HashMap::new(),
type_names: HashMap::new(),
// default print/debug implementations
print: Box::new(default_print),
debug: Box::new(default_print),
// optimization level
#[cfg(feature = "no_optimize")]
optimization_level: OptimizationLevel::None,
#[cfg(not(feature = "no_optimize"))]
#[cfg(not(feature = "optimize_full"))]
optimization_level: OptimizationLevel::Simple,
#[cfg(not(feature = "no_optimize"))]
#[cfg(feature = "optimize_full")]
optimization_level: OptimizationLevel::Full,
max_call_stack_depth: MAX_CALL_STACK_DEPTH,
};
#[cfg(feature = "no_stdlib")]
engine.load_package(CorePackage::new().get());
#[cfg(not(feature = "no_stdlib"))]
engine.load_package(StandardPackage::new().get());
engine
}
}
/// Make getter function
pub fn make_getter(id: &str) -> String {
format!("{}{}", FUNC_GETTER, id)
}
/// Extract the property name from a getter function name.
fn extract_prop_from_getter(fn_name: &str) -> Option<&str> {
#[cfg(not(feature = "no_object"))]
{
if fn_name.starts_with(FUNC_GETTER) {
Some(&fn_name[FUNC_GETTER.len()..])
} else {
None
}
}
#[cfg(feature = "no_object")]
{
None
}
}
/// Make setter function
pub fn make_setter(id: &str) -> String {
format!("{}{}", FUNC_SETTER, id)
}
/// Extract the property name from a setter function name.
fn extract_prop_from_setter(fn_name: &str) -> Option<&str> {
#[cfg(not(feature = "no_object"))]
{
if fn_name.starts_with(FUNC_SETTER) {
Some(&fn_name[FUNC_SETTER.len()..])
} else {
None
}
}
#[cfg(feature = "no_object")]
{
None
}
}
/// Calculate a `u64` hash key from a function name and parameter types.
///
/// Parameter types are passed in via `TypeId` values from an iterator
/// which can come from any source.
pub fn calc_fn_spec(fn_name: &str, params: impl Iterator<Item = TypeId>) -> u64 {
#[cfg(feature = "no_std")]
let mut s: AHasher = Default::default();
#[cfg(not(feature = "no_std"))]
let mut s = DefaultHasher::new();
s.write(fn_name.as_bytes());
params.for_each(|t| t.hash(&mut s));
s.finish()
}
/// Calculate a `u64` hash key from a function name and number of parameters (without regard to types).
pub(crate) fn calc_fn_def(fn_name: &str, params: usize) -> u64 {
#[cfg(feature = "no_std")]
let mut s: AHasher = Default::default();
#[cfg(not(feature = "no_std"))]
let mut s = DefaultHasher::new();
s.write(fn_name.as_bytes());
s.write_usize(params);
s.finish()
}
/// Print/debug to stdout
fn default_print(s: &str) {
#[cfg(not(feature = "no_std"))]
println!("{}", s);
}
/// Search for a variable within the scope, returning its value and index inside the Scope
fn search_scope<'a>(
scope: &'a mut Scope,
name: &str,
begin: Position,
) -> Result<(&'a mut Dynamic, ScopeEntryType), Box<EvalAltResult>> {
let (index, _) = scope
.get(name)
.ok_or_else(|| Box::new(EvalAltResult::ErrorVariableNotFound(name.into(), begin)))?;
Ok(scope.get_mut(index))
}
impl Engine {
/// Create a new `Engine`
pub fn new() -> Self {
Default::default()
}
/// Create a new `Engine` with _no_ built-in functions.
/// Use the `load_package` method to load packages of functions.
pub fn new_raw() -> Self {
Self {
packages: Vec::new(),
functions: HashMap::with_capacity(FUNCTIONS_COUNT / 2),
type_iterators: HashMap::new(),
type_names: HashMap::new(),
print: Box::new(|_| {}),
debug: Box::new(|_| {}),
#[cfg(feature = "no_optimize")]
optimization_level: OptimizationLevel::None,
#[cfg(not(feature = "no_optimize"))]
#[cfg(not(feature = "optimize_full"))]
optimization_level: OptimizationLevel::Simple,
#[cfg(not(feature = "no_optimize"))]
#[cfg(feature = "optimize_full")]
optimization_level: OptimizationLevel::Full,
max_call_stack_depth: MAX_CALL_STACK_DEPTH,
}
}
/// Load a new package into the `Engine`.
///
/// When searching for functions, packages loaded later are preferred.
/// In other words, loaded packages are searched in reverse order.
pub fn load_package(&mut self, package: PackageLibrary) {
// Push the package to the top - packages are searched in reverse order
self.packages.insert(0, package);
}
/// Control whether and how the `Engine` will optimize an AST after compilation
///
/// Not available under the `no_optimize` feature.
#[cfg(not(feature = "no_optimize"))]
pub fn set_optimization_level(&mut self, optimization_level: OptimizationLevel) {
self.optimization_level = optimization_level
}
/// Set the maximum levels of function calls allowed for a script in order to avoid
/// infinite recursion and stack overflows.
pub fn set_max_call_levels(&mut self, levels: usize) {
self.max_call_stack_depth = levels
}
/// Universal method for calling functions either registered with the `Engine` or written in Rhai
pub(crate) fn call_fn_raw(
&self,
scope: Option<&mut Scope>,
fn_lib: &FunctionsLib,
fn_name: &str,
args: &mut FnCallArgs,
def_val: Option<&Dynamic>,
pos: Position,
level: usize,
) -> Result<Dynamic, Box<EvalAltResult>> {
// Check for stack overflow
if level > self.max_call_stack_depth {
return Err(Box::new(EvalAltResult::ErrorStackOverflow(pos)));
}
// First search in script-defined functions (can override built-in)
if let Some(fn_def) = fn_lib.get_function(fn_name, args.len()) {
return self.call_fn_from_lib(scope, fn_lib, fn_def, args, pos, level);
}
// Search built-in's and external functions
let fn_spec = calc_fn_hash(fn_name, args.iter().map(|a| a.type_id()));
if let Some(func) = self.functions.get(&fn_spec).or_else(|| {
self.packages
.iter()
.find(|pkg| pkg.functions.contains_key(&fn_spec))
.and_then(|pkg| pkg.functions.get(&fn_spec))
}) {
// Run external function
let result = func(args, pos)?;
// See if the function match print/debug (which requires special processing)
return Ok(match fn_name {
KEYWORD_PRINT => (self.print)(result.as_str().map_err(|type_name| {
Box::new(EvalAltResult::ErrorMismatchOutputType(
type_name.into(),
pos,
))
})?)
.into(),
KEYWORD_DEBUG => (self.debug)(result.as_str().map_err(|type_name| {
Box::new(EvalAltResult::ErrorMismatchOutputType(
type_name.into(),
pos,
))
})?)
.into(),
_ => result,
});
}
// Getter function not found?
if let Some(prop) = extract_prop_from_getter(fn_name) {
return Err(Box::new(EvalAltResult::ErrorDotExpr(
format!("- property '{}' unknown or write-only", prop),
pos,
)));
}
// Setter function not found?
if let Some(prop) = extract_prop_from_setter(fn_name) {
return Err(Box::new(EvalAltResult::ErrorDotExpr(
format!("- property '{}' unknown or read-only", prop),
pos,
)));
}
// Return default value (if any)
if let Some(val) = def_val {
return Ok(val.clone());
}
// Raise error
let types_list: Vec<_> = args
.iter()
.map(|name| self.map_type_name(name.type_name()))
.collect();
Err(Box::new(EvalAltResult::ErrorFunctionNotFound(
format!("{} ({})", fn_name, types_list.join(", ")),
pos,
)))
}
/// Call a script-defined function.
pub(crate) fn call_fn_from_lib(
&self,
scope: Option<&mut Scope>,
fn_lib: &FunctionsLib,
fn_def: &FnDef,
args: &mut FnCallArgs,
pos: Position,
level: usize,
) -> Result<Dynamic, Box<EvalAltResult>> {
match scope {
// Extern scope passed in which is not empty
Some(scope) if scope.len() > 0 => {
let scope_len = scope.len();
let mut state = State::new();
// Put arguments into scope as variables - variable name is copied
scope.extend(
// TODO - avoid copying variable name
fn_def
.params
.iter()
.zip(args.into_iter().map(|v| v.clone()))
.map(|(name, value)| (name.clone(), ScopeEntryType::Normal, value)),
);
// Evaluate the function at one higher level of call depth
let result = self
.eval_stmt(scope, &mut state, fn_lib, &fn_def.body, level + 1)
.or_else(|err| match *err {
// Convert return statement to return value
EvalAltResult::Return(x, _) => Ok(x),
_ => Err(EvalAltResult::set_position(err, pos)),
});
scope.rewind(scope_len);
return result;
}
// No new scope - create internal scope
_ => {
let mut scope = Scope::new();
let mut state = State::new();
// Put arguments into scope as variables
scope.extend(
fn_def
.params
.iter()
.zip(args.into_iter().map(|v| v.clone()))
.map(|(name, value)| (name, ScopeEntryType::Normal, value)),
);
// Evaluate the function at one higher level of call depth
return self
.eval_stmt(&mut scope, &mut state, fn_lib, &fn_def.body, level + 1)
.or_else(|err| match *err {
// Convert return statement to return value
EvalAltResult::Return(x, _) => Ok(x),
_ => Err(EvalAltResult::set_position(err, pos)),
});
}
}
}
// Has a system function an override?
fn has_override(&self, fn_lib: &FunctionsLib, name: &str) -> bool {
let hash = calc_fn_hash(name, once(TypeId::of::<String>()));
// First check registered functions
self.functions.contains_key(&hash)
// Then check packages
|| self.packages.iter().any(|p| p.functions.contains_key(&hash))
// Then check script-defined functions
|| fn_lib.has_function(name, 1)
}
// Perform an actual function call, taking care of special functions
fn exec_fn_call(
&self,
fn_lib: &FunctionsLib,
fn_name: &str,
args: &mut FnCallArgs,
def_val: Option<&Dynamic>,
pos: Position,
level: usize,
) -> Result<Dynamic, Box<EvalAltResult>> {
match fn_name {
// type_of
KEYWORD_TYPE_OF if args.len() == 1 && !self.has_override(fn_lib, KEYWORD_TYPE_OF) => {
Ok(self.map_type_name(args[0].type_name()).to_string().into())
}
// eval - reaching this point it must be a method-style call
KEYWORD_EVAL if args.len() == 1 && !self.has_override(fn_lib, KEYWORD_EVAL) => {
Err(Box::new(EvalAltResult::ErrorRuntime(
"'eval' should not be called in method style. Try eval(...);".into(),
pos,
)))
}
// Normal method call
_ => self.call_fn_raw(None, fn_lib, fn_name, args, def_val, pos, level),
}
}
/// Evaluate a text string as a script - used primarily for 'eval'.
fn eval_script_expr(
&self,
scope: &mut Scope,
fn_lib: &FunctionsLib,
script: &Dynamic,
pos: Position,
) -> Result<Dynamic, Box<EvalAltResult>> {
let script = script
.as_str()
.map_err(|type_name| EvalAltResult::ErrorMismatchOutputType(type_name.into(), pos))?;
// Compile the script text
// No optimizations because we only run it once
let mut ast = self.compile_with_scope_and_optimization_level(
&Scope::new(),
script,
OptimizationLevel::None,
)?;
// If new functions are defined within the eval string, it is an error
if ast.1.len() > 0 {
return Err(Box::new(EvalAltResult::ErrorParsing(
ParseErrorType::WrongFnDefinition.into_err(pos),
)));
}
#[cfg(feature = "sync")]
{
ast.1 = Arc::new(fn_lib.clone());
}
#[cfg(not(feature = "sync"))]
{
ast.1 = Rc::new(fn_lib.clone());
}
// Evaluate the AST
self.eval_ast_with_scope_raw(scope, &ast)
.map_err(|err| EvalAltResult::set_position(err, pos))
}
/// Chain-evaluate a dot/index chain.
fn eval_dot_index_chain_helper(
&self,
fn_lib: &FunctionsLib,
mut target: Target,
rhs: &Expr,
idx_values: &mut StaticVec<Dynamic>,
is_index: bool,
op_pos: Position,
level: usize,
mut new_val: Option<Dynamic>,
) -> Result<(Dynamic, bool), Box<EvalAltResult>> {
// Get a reference to the mutation target Dynamic
let obj = match target {
Target::Ref(r) => r,
Target::Value(ref mut r) => r.as_mut(),
Target::StringChar(ref mut x) => &mut x.2,
};
// Pop the last index value
let mut idx_val = idx_values.pop();
if is_index {
match rhs {
// xxx[idx].dot_rhs...
Expr::Dot(idx, idx_rhs, pos) |
// xxx[idx][dot_rhs]...
Expr::Index(idx, idx_rhs, pos) => {
let is_index = matches!(rhs, Expr::Index(_,_,_));
let indexed_val = self.get_indexed_mut(obj, idx_val, idx.position(), op_pos, false)?;
self.eval_dot_index_chain_helper(
fn_lib, indexed_val, idx_rhs.as_ref(), idx_values, is_index, *pos, level, new_val
)
}
// xxx[rhs] = new_val
_ if new_val.is_some() => {
let mut indexed_val = self.get_indexed_mut(obj, idx_val, rhs.position(), op_pos, true)?;
indexed_val.set_value(new_val.unwrap(), rhs.position())?;
Ok((Default::default(), true))
}
// xxx[rhs]
_ => self
.get_indexed_mut(obj, idx_val, rhs.position(), op_pos, false)
.map(|v| (v.clone_into_dynamic(), false))
}
} else {
match rhs {
// xxx.fn_name(arg_expr_list)
Expr::FnCall(fn_name, _, def_val, pos) => {
let mut args: Vec<_> = once(obj)
.chain(idx_val.downcast_mut::<Array>().unwrap().iter_mut())
.collect();
let def_val = def_val.as_deref();
// A function call is assumed to have side effects, so the value is changed
// TODO - Remove assumption of side effects by checking whether the first parameter is &mut
self.exec_fn_call(fn_lib, fn_name, &mut args, def_val, *pos, 0).map(|v| (v, true))
}
// {xxx:map}.id = ???
Expr::Property(id, pos) if obj.is::<Map>() && new_val.is_some() => {
let mut indexed_val =
self.get_indexed_mut(obj, id.to_string().into(), *pos, op_pos, true)?;
indexed_val.set_value(new_val.unwrap(), rhs.position())?;
Ok((Default::default(), true))
}
// {xxx:map}.id
Expr::Property(id, pos) if obj.is::<Map>() => {
let indexed_val =
self.get_indexed_mut(obj, id.to_string().into(), *pos, op_pos, false)?;
Ok((indexed_val.clone_into_dynamic(), false))
}
// xxx.id = ???
Expr::Property(id, pos) if new_val.is_some() => {
let fn_name = make_setter(id);
let mut args = [obj, new_val.as_mut().unwrap()];
self.exec_fn_call(fn_lib, &fn_name, &mut args, None, *pos, 0).map(|v| (v, true))
}
// xxx.id
Expr::Property(id, pos) => {
let fn_name = make_getter(id);
let mut args = [obj];
self.exec_fn_call(fn_lib, &fn_name, &mut args, None, *pos, 0).map(|v| (v, false))
}
// {xxx:map}.idx_lhs[idx_expr]
Expr::Index(dot_lhs, dot_rhs, pos) |
// {xxx:map}.dot_lhs.rhs
Expr::Dot(dot_lhs, dot_rhs, pos) if obj.is::<Map>() => {
let is_index = matches!(rhs, Expr::Index(_,_,_));
let indexed_val = if let Expr::Property(id, pos) = dot_lhs.as_ref() {
self.get_indexed_mut(obj, id.to_string().into(), *pos, op_pos, false)?
} else {
// Syntax error
return Err(Box::new(EvalAltResult::ErrorDotExpr(
"".to_string(),
rhs.position(),
)));
};
self.eval_dot_index_chain_helper(
fn_lib, indexed_val, dot_rhs, idx_values, is_index, *pos, level, new_val
)
}
// xxx.idx_lhs[idx_expr]
Expr::Index(dot_lhs, dot_rhs, pos) |
// xxx.dot_lhs.rhs
Expr::Dot(dot_lhs, dot_rhs, pos) => {
let is_index = matches!(rhs, Expr::Index(_,_,_));
let mut args = [obj, &mut Default::default()];
let indexed_val = &mut (if let Expr::Property(id, pos) = dot_lhs.as_ref() {
let fn_name = make_getter(id);
self.exec_fn_call(fn_lib, &fn_name, &mut args[..1], None, *pos, 0)?
} else {
// Syntax error
return Err(Box::new(EvalAltResult::ErrorDotExpr(
"".to_string(),
rhs.position(),
)));
});
let (result, may_be_changed) = self.eval_dot_index_chain_helper(
fn_lib, indexed_val.into(), dot_rhs, idx_values, is_index, *pos, level, new_val
)?;
// Feed the value back via a setter just in case it has been updated
if may_be_changed {
if let Expr::Property(id, pos) = dot_lhs.as_ref() {
let fn_name = make_setter(id);
args[1] = indexed_val;
self.exec_fn_call(fn_lib, &fn_name, &mut args, None, *pos, 0)?;
}
}
Ok((result, may_be_changed))
}
// Syntax error
_ => Err(Box::new(EvalAltResult::ErrorDotExpr(
"".to_string(),
rhs.position(),
))),
}
}
}
/// Evaluate a dot/index chain.
fn eval_dot_index_chain(
&self,
scope: &mut Scope,
state: &mut State,
fn_lib: &FunctionsLib,
dot_lhs: &Expr,
dot_rhs: &Expr,
is_index: bool,
op_pos: Position,
level: usize,
new_val: Option<Dynamic>,
) -> Result<Dynamic, Box<EvalAltResult>> {
let idx_values = &mut StaticVec::new();
self.eval_indexed_chain(scope, state, fn_lib, dot_rhs, idx_values, 0, level)?;
match dot_lhs {
// id.??? or id[???]
Expr::Variable(id, index, pos) => {
let (target, typ) = match index {
Some(i) if !state.always_search => scope.get_mut(scope.len() - i.get()),
_ => search_scope(scope, id, *pos)?,
};
// Constants cannot be modified
match typ {
ScopeEntryType::Constant if new_val.is_some() => {
return Err(Box::new(EvalAltResult::ErrorAssignmentToConstant(
id.to_string(),
*pos,
)));
}
_ => (),
}
let this_ptr = target.into();
self.eval_dot_index_chain_helper(
fn_lib, this_ptr, dot_rhs, idx_values, is_index, op_pos, level, new_val,
)
.map(|(v, _)| v)
}
// {expr}.??? = ??? or {expr}[???] = ???
expr if new_val.is_some() => {
return Err(Box::new(EvalAltResult::ErrorAssignmentToUnknownLHS(
expr.position(),
)));
}
// {expr}.??? or {expr}[???]
expr => {
let val = self.eval_expr(scope, state, fn_lib, expr, level)?;
let this_ptr = val.into();
self.eval_dot_index_chain_helper(
fn_lib, this_ptr, dot_rhs, idx_values, is_index, op_pos, level, new_val,
)
.map(|(v, _)| v)
}
}
}
/// Evaluate a chain of indexes and store the results in a list.
/// The first few results are stored in the array `list` which is of fixed length.
/// Any spill-overs are stored in `more`, which is dynamic.
/// The fixed length array is used to avoid an allocation in the overwhelming cases of just a few levels of indexing.
/// The total number of values is returned.
fn eval_indexed_chain(
&self,
scope: &mut Scope,
state: &mut State,
fn_lib: &FunctionsLib,
expr: &Expr,
idx_values: &mut StaticVec<Dynamic>,
size: usize,
level: usize,
) -> Result<(), Box<EvalAltResult>> {
match expr {
Expr::FnCall(_, arg_exprs, _, _) => {
let arg_values = arg_exprs
.iter()
.map(|arg_expr| self.eval_expr(scope, state, fn_lib, arg_expr, level))
.collect::<Result<Vec<_>, _>>()?;
idx_values.push(arg_values)
}
Expr::Property(_, _) => idx_values.push(()), // Store a placeholder - no need to copy the property name
Expr::Index(lhs, rhs, _) | Expr::Dot(lhs, rhs, _) => {
// Evaluate in left-to-right order
let lhs_val = match lhs.as_ref() {
Expr::Property(_, _) => Default::default(), // Store a placeholder in case of a property
_ => self.eval_expr(scope, state, fn_lib, lhs, level)?,
};
// Push in reverse order
self.eval_indexed_chain(scope, state, fn_lib, rhs, idx_values, size, level)?;
idx_values.push(lhs_val);
}
_ => idx_values.push(self.eval_expr(scope, state, fn_lib, expr, level)?),
}
Ok(())
}
/// Get the value at the indexed position of a base type
fn get_indexed_mut<'a>(
&self,
val: &'a mut Dynamic,
idx: Dynamic,
idx_pos: Position,
op_pos: Position,
create: bool,
) -> Result<Target<'a>, Box<EvalAltResult>> {
let type_name = self.map_type_name(val.type_name());
match val {
Dynamic(Union::Array(arr)) => {
// val_array[idx]
let index = idx
.as_int()
.map_err(|_| EvalAltResult::ErrorNumericIndexExpr(idx_pos))?;
let arr_len = arr.len();
if index >= 0 {
arr.get_mut(index as usize)
.map(Target::from)
.ok_or_else(|| {
Box::new(EvalAltResult::ErrorArrayBounds(arr_len, index, idx_pos))
})
} else {
Err(Box::new(EvalAltResult::ErrorArrayBounds(
arr_len, index, idx_pos,
)))
}
}
Dynamic(Union::Map(map)) => {
// val_map[idx]
let index = idx
.take_string()
.map_err(|_| EvalAltResult::ErrorStringIndexExpr(idx_pos))?;
Ok(if create {
map.entry(index).or_insert(Default::default()).into()
} else {
map.get_mut(&index)
.map(Target::from)
.unwrap_or_else(|| Target::from(()))
})
}
Dynamic(Union::Str(s)) => {
// val_string[idx]
let index = idx
.as_int()
.map_err(|_| EvalAltResult::ErrorNumericIndexExpr(idx_pos))?;
if index >= 0 {
let ch = s.chars().nth(index as usize).ok_or_else(|| {
Box::new(EvalAltResult::ErrorStringBounds(
s.chars().count(),
index,
idx_pos,
))
})?;
Ok(Target::StringChar(Box::new((
val,
index as usize,
ch.into(),
))))
} else {
Err(Box::new(EvalAltResult::ErrorStringBounds(
s.chars().count(),
index,
idx_pos,
)))
}
}
// Error - cannot be indexed
_ => Err(Box::new(EvalAltResult::ErrorIndexingType(
type_name.to_string(),
op_pos,
))),
}
}
// Evaluate an 'in' expression
fn eval_in_expr(
&self,
scope: &mut Scope,
state: &mut State,
fn_lib: &FunctionsLib,
lhs: &Expr,
rhs: &Expr,
level: usize,
) -> Result<Dynamic, Box<EvalAltResult>> {
let mut lhs_value = self.eval_expr(scope, state, fn_lib, lhs, level)?;
let rhs_value = self.eval_expr(scope, state, fn_lib, rhs, level)?;
match rhs_value {
Dynamic(Union::Array(mut rhs_value)) => {
let def_value = false.into();
// Call the '==' operator to compare each value
for value in rhs_value.iter_mut() {
let args = &mut [&mut lhs_value, value];
let def_value = Some(&def_value);
if self
.call_fn_raw(None, fn_lib, "==", args, def_value, rhs.position(), level)?
.as_bool()
.unwrap_or(false)
{
return Ok(true.into());
}
}
Ok(false.into())
}
Dynamic(Union::Map(rhs_value)) => match lhs_value {
// Only allows String or char
Dynamic(Union::Str(s)) => Ok(rhs_value.contains_key(s.as_ref()).into()),
Dynamic(Union::Char(c)) => Ok(rhs_value.contains_key(&c.to_string()).into()),
_ => Err(Box::new(EvalAltResult::ErrorInExpr(lhs.position()))),
},
Dynamic(Union::Str(rhs_value)) => match lhs_value {
// Only allows String or char
Dynamic(Union::Str(s)) => Ok(rhs_value.contains(s.as_ref()).into()),
Dynamic(Union::Char(c)) => Ok(rhs_value.contains(c).into()),
_ => Err(Box::new(EvalAltResult::ErrorInExpr(lhs.position()))),
},
_ => Err(Box::new(EvalAltResult::ErrorInExpr(rhs.position()))),
}
}
/// Evaluate an expression
fn eval_expr(
&self,
scope: &mut Scope,
state: &mut State,
fn_lib: &FunctionsLib,
expr: &Expr,
level: usize,
) -> Result<Dynamic, Box<EvalAltResult>> {
match expr {
Expr::IntegerConstant(i, _) => Ok((*i).into()),
#[cfg(not(feature = "no_float"))]
Expr::FloatConstant(f, _) => Ok((*f).into()),
Expr::StringConstant(s, _) => Ok(s.to_string().into()),
Expr::CharConstant(c, _) => Ok((*c).into()),
Expr::Variable(_, Some(index), _) if !state.always_search => {
Ok(scope.get_mut(scope.len() - index.get()).0.clone())
}
Expr::Variable(id, _, pos) => search_scope(scope, id, *pos).map(|(v, _)| v.clone()),
Expr::Property(_, _) => panic!("unexpected property."),
// Statement block
Expr::Stmt(stmt, _) => self.eval_stmt(scope, state, fn_lib, stmt, level),
// lhs = rhs
Expr::Assignment(lhs, rhs, op_pos) => {
let rhs_val = self.eval_expr(scope, state, fn_lib, rhs, level)?;
match lhs.as_ref() {
// name = rhs
Expr::Variable(name, _, pos) => match scope.get(name) {
None => {
return Err(Box::new(EvalAltResult::ErrorVariableNotFound(
name.to_string(),
*pos,
)))
}
Some((_, ScopeEntryType::Constant)) => Err(Box::new(
EvalAltResult::ErrorAssignmentToConstant(name.to_string(), *op_pos),
)),
Some((index, ScopeEntryType::Normal)) => {
*scope.get_mut(index).0 = rhs_val;
Ok(Default::default())
}
},
// idx_lhs[idx_expr] = rhs
#[cfg(not(feature = "no_index"))]
Expr::Index(idx_lhs, idx_expr, op_pos) => {
let new_val = Some(rhs_val);
self.eval_dot_index_chain(
scope, state, fn_lib, idx_lhs, idx_expr, true, *op_pos, level, new_val,
)
}
// dot_lhs.dot_rhs = rhs
#[cfg(not(feature = "no_object"))]
Expr::Dot(dot_lhs, dot_rhs, _) => {
let new_val = Some(rhs_val);
self.eval_dot_index_chain(
scope, state, fn_lib, dot_lhs, dot_rhs, false, *op_pos, level, new_val,
)
}
// Error assignment to constant
expr if expr.is_constant() => {
Err(Box::new(EvalAltResult::ErrorAssignmentToConstant(
expr.get_constant_str(),
lhs.position(),
)))
}
// Syntax error
_ => Err(Box::new(EvalAltResult::ErrorAssignmentToUnknownLHS(
lhs.position(),
))),
}
}
// lhs[idx_expr]
#[cfg(not(feature = "no_index"))]
Expr::Index(lhs, idx_expr, op_pos) => self.eval_dot_index_chain(
scope, state, fn_lib, lhs, idx_expr, true, *op_pos, level, None,
),
// lhs.dot_rhs
#[cfg(not(feature = "no_object"))]
Expr::Dot(lhs, dot_rhs, op_pos) => self.eval_dot_index_chain(
scope, state, fn_lib, lhs, dot_rhs, false, *op_pos, level, None,
),
#[cfg(not(feature = "no_index"))]
Expr::Array(contents, _) => Ok(Dynamic(Union::Array(Box::new(
contents
.iter()
.map(|item| self.eval_expr(scope, state, fn_lib, item, level))
.collect::<Result<Vec<_>, _>>()?,
)))),
#[cfg(not(feature = "no_object"))]
Expr::Map(contents, _) => Ok(Dynamic(Union::Map(Box::new(
contents
.iter()
.map(|(key, expr, _)| {
self.eval_expr(scope, state, fn_lib, expr, level)
.map(|val| (key.clone(), val))
})
.collect::<Result<HashMap<_, _>, _>>()?,
)))),
Expr::FnCall(fn_name, arg_exprs, def_val, pos) => {
let mut arg_values = arg_exprs
.iter()
.map(|expr| self.eval_expr(scope, state, fn_lib, expr, level))
.collect::<Result<Vec<_>, _>>()?;
let mut args: Vec<_> = arg_values.iter_mut().collect();
// eval - only in function call style
if fn_name.as_ref() == KEYWORD_EVAL
&& args.len() == 1
&& !self.has_override(fn_lib, KEYWORD_EVAL)
{
let prev_len = scope.len();
// Evaluate the text string as a script
let result =
self.eval_script_expr(scope, fn_lib, args[0], arg_exprs[0].position());
if scope.len() != prev_len {
// IMPORTANT! If the eval defines new variables in the current scope,
// all variable offsets from this point on will be mis-aligned.
state.always_search = true;
}
return result;
}
// Normal function call - except for eval (handled above)
self.exec_fn_call(fn_lib, fn_name, &mut args, def_val.as_deref(), *pos, level)
}
Expr::In(lhs, rhs, _) => {
self.eval_in_expr(scope, state, fn_lib, lhs.as_ref(), rhs.as_ref(), level)
}
Expr::And(lhs, rhs, _) => Ok((self
.eval_expr(scope, state, fn_lib, lhs.as_ref(), level)?
.as_bool()
.map_err(|_| {
EvalAltResult::ErrorBooleanArgMismatch("AND".into(), lhs.position())
})?
&& // Short-circuit using &&
self
.eval_expr(scope, state, fn_lib, rhs.as_ref(), level)?
.as_bool()
.map_err(|_| {
EvalAltResult::ErrorBooleanArgMismatch("AND".into(), rhs.position())
})?)
.into()),
Expr::Or(lhs, rhs, _) => Ok((self
.eval_expr(scope, state, fn_lib, lhs.as_ref(), level)?
.as_bool()
.map_err(|_| {
EvalAltResult::ErrorBooleanArgMismatch("OR".into(), lhs.position())
})?
|| // Short-circuit using ||
self
.eval_expr(scope, state, fn_lib, rhs.as_ref(), level)?
.as_bool()
.map_err(|_| {
EvalAltResult::ErrorBooleanArgMismatch("OR".into(), rhs.position())
})?)
.into()),
Expr::True(_) => Ok(true.into()),
Expr::False(_) => Ok(false.into()),
Expr::Unit(_) => Ok(().into()),
_ => panic!("should not appear: {:?}", expr),
}
}
/// Evaluate a statement
pub(crate) fn eval_stmt(
&self,
scope: &mut Scope,
state: &mut State,
fn_lib: &FunctionsLib,
stmt: &Stmt,
level: usize,
) -> Result<Dynamic, Box<EvalAltResult>> {
match stmt {
// No-op
Stmt::Noop(_) => Ok(Default::default()),
// Expression as statement
Stmt::Expr(expr) => {
let result = self.eval_expr(scope, state, fn_lib, expr, level)?;
Ok(if let Expr::Assignment(_, _, _) = *expr.as_ref() {
// If it is an assignment, erase the result at the root
Default::default()
} else {
result
})
}
// Block scope
Stmt::Block(block, _) => {
let prev_len = scope.len();
let result = block.iter().try_fold(Default::default(), |_, stmt| {
self.eval_stmt(scope, state, fn_lib, stmt, level)
});
scope.rewind(prev_len);
// The impact of an eval statement goes away at the end of a block
// because any new variables introduced will go out of scope
state.always_search = false;
result
}
// If-else statement
Stmt::IfThenElse(guard, if_body, else_body) => self
.eval_expr(scope, state, fn_lib, guard, level)?
.as_bool()
.map_err(|_| Box::new(EvalAltResult::ErrorLogicGuard(guard.position())))
.and_then(|guard_val| {
if guard_val {
self.eval_stmt(scope, state, fn_lib, if_body, level)
} else if let Some(stmt) = else_body {
self.eval_stmt(scope, state, fn_lib, stmt.as_ref(), level)
} else {
Ok(Default::default())
}
}),
// While loop
Stmt::While(guard, body) => loop {
match self
.eval_expr(scope, state, fn_lib, guard, level)?
.as_bool()
{
Ok(true) => match self.eval_stmt(scope, state, fn_lib, body, level) {
Ok(_) => (),
Err(err) => match *err {
EvalAltResult::ErrorLoopBreak(false, _) => (),
EvalAltResult::ErrorLoopBreak(true, _) => return Ok(Default::default()),
_ => return Err(err),
},
},
Ok(false) => return Ok(Default::default()),
Err(_) => {
return Err(Box::new(EvalAltResult::ErrorLogicGuard(guard.position())))
}
}
},
// Loop statement
Stmt::Loop(body) => loop {
match self.eval_stmt(scope, state, fn_lib, body, level) {
Ok(_) => (),
Err(err) => match *err {
EvalAltResult::ErrorLoopBreak(false, _) => (),
EvalAltResult::ErrorLoopBreak(true, _) => return Ok(Default::default()),
_ => return Err(err),
},
}
},
// For loop
Stmt::For(name, expr, body) => {
let arr = self.eval_expr(scope, state, fn_lib, expr, level)?;
let tid = arr.type_id();
if let Some(iter_fn) = self.type_iterators.get(&tid).or_else(|| {
self.packages
.iter()
.find(|pkg| pkg.type_iterators.contains_key(&tid))
.and_then(|pkg| pkg.type_iterators.get(&tid))
}) {
// Add the loop variable
let var_name = name.as_ref().clone();
scope.push(var_name, ());
let index = scope.len() - 1;
for a in iter_fn(arr) {
*scope.get_mut(index).0 = a;
match self.eval_stmt(scope, state, fn_lib, body, level) {
Ok(_) => (),
Err(err) => match *err {
EvalAltResult::ErrorLoopBreak(false, _) => (),
EvalAltResult::ErrorLoopBreak(true, _) => break,
_ => return Err(err),
},
}
}
scope.rewind(scope.len() - 1);
Ok(Default::default())
} else {
Err(Box::new(EvalAltResult::ErrorFor(expr.position())))
}
}
// Continue statement
Stmt::Continue(pos) => Err(Box::new(EvalAltResult::ErrorLoopBreak(false, *pos))),
// Break statement
Stmt::Break(pos) => Err(Box::new(EvalAltResult::ErrorLoopBreak(true, *pos))),
// Empty return
Stmt::ReturnWithVal(None, ReturnType::Return, pos) => {
Err(Box::new(EvalAltResult::Return(Default::default(), *pos)))
}
// Return value
Stmt::ReturnWithVal(Some(a), ReturnType::Return, pos) => Err(Box::new(
EvalAltResult::Return(self.eval_expr(scope, state, fn_lib, a, level)?, *pos),
)),
// Empty throw
Stmt::ReturnWithVal(None, ReturnType::Exception, pos) => {
Err(Box::new(EvalAltResult::ErrorRuntime("".into(), *pos)))
}
// Throw value
Stmt::ReturnWithVal(Some(a), ReturnType::Exception, pos) => {
let val = self.eval_expr(scope, state, fn_lib, a, level)?;
Err(Box::new(EvalAltResult::ErrorRuntime(
val.take_string().unwrap_or_else(|_| "".to_string()),
*pos,
)))
}
// Let statement
Stmt::Let(name, Some(expr), _) => {
let val = self.eval_expr(scope, state, fn_lib, expr, level)?;
// TODO - avoid copying variable name in inner block?
let var_name = name.as_ref().clone();
scope.push_dynamic_value(var_name, ScopeEntryType::Normal, val, false);
Ok(Default::default())
}
Stmt::Let(name, None, _) => {
// TODO - avoid copying variable name in inner block?
let var_name = name.as_ref().clone();
scope.push(var_name, ());
Ok(Default::default())
}
// Const statement
Stmt::Const(name, expr, _) if expr.is_constant() => {
let val = self.eval_expr(scope, state, fn_lib, expr, level)?;
// TODO - avoid copying variable name in inner block?
let var_name = name.as_ref().clone();
scope.push_dynamic_value(var_name, ScopeEntryType::Constant, val, true);
Ok(Default::default())
}
Stmt::Const(_, _, _) => panic!("constant expression not constant!"),
}
}
/// Map a type_name into a pretty-print name
pub(crate) fn map_type_name<'a>(&'a self, name: &'a str) -> &'a str {
self.type_names
.get(name)
.map(String::as_str)
.unwrap_or(name)
}
}
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