rhai/src/eval/stmt.rs
2023-03-16 19:00:59 +08:00

980 lines
39 KiB
Rust

//! Module defining functions for evaluating a statement.
use super::{Caches, EvalContext, GlobalRuntimeState, Target};
use crate::api::events::VarDefInfo;
use crate::ast::{
ASTFlags, BinaryExpr, ConditionalExpr, Expr, FlowControl, OpAssignment, Stmt,
SwitchCasesCollection,
};
use crate::func::{get_builtin_op_assignment_fn, get_hasher};
use crate::tokenizer::Token;
use crate::types::dynamic::{AccessMode, Union};
use crate::{Dynamic, Engine, RhaiResult, RhaiResultOf, Scope, ERR, INT};
use std::hash::{Hash, Hasher};
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
impl Dynamic {
/// If the value is a string, intern it.
#[inline(always)]
fn intern_string(self, engine: &Engine) -> Self {
match self.0 {
Union::Str(..) => engine
.get_interned_string(self.into_immutable_string().expect("`ImmutableString`"))
.into(),
_ => self,
}
}
}
impl Engine {
/// Evaluate a statements block.
pub(crate) fn eval_stmt_block(
&self,
global: &mut GlobalRuntimeState,
caches: &mut Caches,
scope: &mut Scope,
mut this_ptr: Option<&mut Dynamic>,
statements: &[Stmt],
restore_orig_state: bool,
) -> RhaiResult {
if statements.is_empty() {
return Ok(Dynamic::UNIT);
}
// Restore scope at end of block if necessary
auto_restore! { scope if restore_orig_state => rewind; let orig_scope_len = scope.len(); }
// Restore global state at end of block if necessary
let orig_always_search_scope = global.always_search_scope;
#[cfg(not(feature = "no_module"))]
let orig_imports_len = global.num_imports();
if restore_orig_state {
global.scope_level += 1;
}
auto_restore!(global if restore_orig_state => move |g| {
g.scope_level -= 1;
#[cfg(not(feature = "no_module"))]
g.truncate_imports(orig_imports_len);
// The impact of new local variables goes away at the end of a block
// because any new variables introduced will go out of scope
g.always_search_scope = orig_always_search_scope;
});
// Pop new function resolution caches at end of block
auto_restore! {
caches => rewind_fn_resolution_caches;
let orig_fn_resolution_caches_len = caches.fn_resolution_caches_len();
}
// Run the statements
statements.iter().try_fold(Dynamic::UNIT, |_, stmt| {
let this_ptr = this_ptr.as_deref_mut();
#[cfg(not(feature = "no_module"))]
let imports_len = global.num_imports();
let result =
self.eval_stmt(global, caches, scope, this_ptr, stmt, restore_orig_state)?;
#[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 global
.scan_imports_raw()
.skip(imports_len)
.any(|(.., m)| m.contains_indexed_global_functions())
{
// Different scenarios where the cache must be cleared - notice that this is
// expensive as all function resolutions must start again
if caches.fn_resolution_caches_len() > orig_fn_resolution_caches_len {
// When new module is imported with global functions and there is already
// a new cache, just clear it
caches.fn_resolution_cache_mut().clear();
} else if restore_orig_state {
// When new module is imported with global functions, push a new cache
caches.push_fn_resolution_cache();
} else {
// When the block is to be evaluated in-place, just clear the current cache
caches.fn_resolution_cache_mut().clear();
}
}
}
Ok(result)
})
}
/// Evaluate an op-assignment statement.
pub(crate) fn eval_op_assignment(
&self,
global: &mut GlobalRuntimeState,
caches: &mut Caches,
op_info: &OpAssignment,
root: &Expr,
target: &mut Target,
mut new_val: Dynamic,
) -> RhaiResultOf<()> {
// Assignment to constant variable?
if target.is_read_only() {
let name = root.get_variable_name(false).unwrap_or_default();
let pos = root.start_position();
return Err(ERR::ErrorAssignmentToConstant(name.to_string(), pos).into());
}
let pos = op_info.position();
if let Some((hash_x, hash, op_x, op_x_str, op, op_str)) = op_info.get_op_assignment_info() {
let mut lock_guard = target.write_lock::<Dynamic>().unwrap();
let mut done = false;
// Short-circuit built-in op-assignments if under Fast Operators mode
if self.fast_operators() {
#[allow(clippy::wildcard_imports)]
use Token::*;
done = true;
// For extremely simple primary data operations, do it directly
// to avoid the overhead of calling a function.
match (&mut lock_guard.0, &mut new_val.0) {
(Union::Bool(b1, ..), Union::Bool(b2, ..)) => match op_x {
AndAssign => *b1 = *b1 && *b2,
OrAssign => *b1 = *b1 || *b2,
XOrAssign => *b1 = *b1 ^ *b2,
_ => done = false,
},
(Union::Int(n1, ..), Union::Int(n2, ..)) => {
#[cfg(not(feature = "unchecked"))]
#[allow(clippy::wildcard_imports)]
use crate::packages::arithmetic::arith_basic::INT::functions::*;
#[cfg(not(feature = "unchecked"))]
match op_x {
PlusAssign => {
*n1 = add(*n1, *n2).map_err(|err| err.fill_position(pos))?
}
MinusAssign => {
*n1 = subtract(*n1, *n2).map_err(|err| err.fill_position(pos))?
}
MultiplyAssign => {
*n1 = multiply(*n1, *n2).map_err(|err| err.fill_position(pos))?
}
DivideAssign => {
*n1 = divide(*n1, *n2).map_err(|err| err.fill_position(pos))?
}
ModuloAssign => {
*n1 = modulo(*n1, *n2).map_err(|err| err.fill_position(pos))?
}
_ => done = false,
}
#[cfg(feature = "unchecked")]
match op_x {
PlusAssign => *n1 += *n2,
MinusAssign => *n1 -= *n2,
MultiplyAssign => *n1 *= *n2,
DivideAssign => *n1 /= *n2,
ModuloAssign => *n1 %= *n2,
_ => done = false,
}
}
#[cfg(not(feature = "no_float"))]
(Union::Float(f1, ..), Union::Float(f2, ..)) => match op_x {
PlusAssign => **f1 += **f2,
MinusAssign => **f1 -= **f2,
MultiplyAssign => **f1 *= **f2,
DivideAssign => **f1 /= **f2,
ModuloAssign => **f1 %= **f2,
_ => done = false,
},
#[cfg(not(feature = "no_float"))]
(Union::Float(f1, ..), Union::Int(n2, ..)) => match op_x {
PlusAssign => **f1 += *n2 as crate::FLOAT,
MinusAssign => **f1 -= *n2 as crate::FLOAT,
MultiplyAssign => **f1 *= *n2 as crate::FLOAT,
DivideAssign => **f1 /= *n2 as crate::FLOAT,
ModuloAssign => **f1 %= *n2 as crate::FLOAT,
_ => done = false,
},
_ => done = false,
}
if !done {
if let Some((func, need_context)) =
get_builtin_op_assignment_fn(op_x, &*lock_guard, &new_val)
{
// We may not need to bump the level because built-in's do not need it.
//auto_restore! { let orig_level = global.level; global.level += 1 }
let args = &mut [&mut *lock_guard, &mut new_val];
let context = need_context
.then(|| (self, op_x_str, global.source(), &*global, pos).into());
let _ = func(context, args).map_err(|err| err.fill_position(pos))?;
done = true;
}
}
}
if !done {
let opx = Some(op_x);
let args = &mut [&mut *lock_guard, &mut new_val];
match self
.exec_native_fn_call(global, caches, op_x_str, opx, hash_x, args, true, pos)
{
Ok(_) => (),
Err(err) if matches!(*err, ERR::ErrorFunctionNotFound(ref f, ..) if f.starts_with(op_x_str)) =>
{
// Expand to `var = var op rhs`
let op = Some(op);
*args[0] = self
.exec_native_fn_call(global, caches, op_str, op, hash, args, true, pos)?
.0;
}
Err(err) => return Err(err),
}
self.check_data_size(&*args[0], root.position())?;
}
} else {
// Normal assignment
match target {
// Lock it again just in case it is shared
Target::RefMut(_) | Target::TempValue(_) => {
*target.write_lock::<Dynamic>().unwrap() = new_val
}
#[allow(unreachable_patterns)]
_ => **target = new_val,
}
}
target.propagate_changed_value(pos)
}
/// Evaluate a statement.
pub(crate) fn eval_stmt(
&self,
global: &mut GlobalRuntimeState,
caches: &mut Caches,
scope: &mut Scope,
mut this_ptr: Option<&mut Dynamic>,
stmt: &Stmt,
rewind_scope: bool,
) -> RhaiResult {
#[cfg(feature = "debugging")]
let reset =
self.run_debugger_with_reset(global, caches, scope, this_ptr.as_deref_mut(), stmt)?;
#[cfg(feature = "debugging")]
auto_restore!(global if Some(reset) => move |g| g.debugger_mut().reset_status(reset));
self.track_operation(global, stmt.position())?;
// Coded this way for better branch prediction.
// Popular branches are lifted out of the `match` statement into their own branches.
// Function calls should account for a relatively larger portion of statements.
if let Stmt::FnCall(x, pos) = stmt {
return self.eval_fn_call_expr(global, caches, scope, this_ptr, x, *pos);
}
// Then assignments.
if let Stmt::Assignment(x, ..) = stmt {
let (op_info, BinaryExpr { lhs, rhs }) = &**x;
if let Expr::Variable(x, ..) = lhs {
let rhs_val = self
.eval_expr(global, caches, scope, this_ptr.as_deref_mut(), rhs)?
.flatten();
let mut target = self.search_namespace(global, caches, scope, this_ptr, lhs)?;
let is_temp_result = !target.is_ref();
let var_name = x.3.as_str();
#[cfg(not(feature = "no_closure"))]
// Also handle case where target is a `Dynamic` shared value
// (returned by a variable resolver, for example)
let is_temp_result = is_temp_result && !target.is_shared();
// Cannot assign to temp result from expression
if is_temp_result {
return Err(ERR::ErrorAssignmentToConstant(
var_name.to_string(),
lhs.position(),
)
.into());
}
self.track_operation(global, lhs.position())?;
self.eval_op_assignment(global, caches, op_info, lhs, &mut target, rhs_val)?;
return Ok(Dynamic::UNIT);
}
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
{
let rhs_val = self
.eval_expr(global, caches, scope, this_ptr.as_deref_mut(), rhs)?
.flatten()
.intern_string(self);
let _new_val = Some((rhs_val, op_info));
// Must be either `var[index] op= val` or `var.prop op= val`.
// The return value of any op-assignment (should be `()`) is thrown away and not used.
let _ =
match lhs {
// name op= rhs (handled above)
Expr::Variable(..) => {
unreachable!("Expr::Variable case is already handled")
}
// idx_lhs[idx_expr] op= rhs
#[cfg(not(feature = "no_index"))]
Expr::Index(..) => self
.eval_dot_index_chain(global, caches, scope, this_ptr, lhs, _new_val),
// dot_lhs.dot_rhs op= rhs
#[cfg(not(feature = "no_object"))]
Expr::Dot(..) => self
.eval_dot_index_chain(global, caches, scope, this_ptr, lhs, _new_val),
_ => unreachable!("cannot assign to expression: {:?}", lhs),
}?;
return Ok(Dynamic::UNIT);
}
}
// Then variable definitions.
if let Stmt::Var(x, options, pos) = stmt {
if !self.allow_shadowing() && scope.contains(&x.0) {
return Err(ERR::ErrorVariableExists(x.0.to_string(), *pos).into());
}
// Let/const statement
let (var_name, expr, index) = &**x;
let access = if options.contains(ASTFlags::CONSTANT) {
AccessMode::ReadOnly
} else {
AccessMode::ReadWrite
};
let export = options.contains(ASTFlags::EXPORTED);
// Check variable definition filter
if let Some(ref filter) = self.def_var_filter {
let will_shadow = scope.contains(var_name);
let is_const = access == AccessMode::ReadOnly;
let info = VarDefInfo {
name: var_name,
is_const,
nesting_level: global.scope_level,
will_shadow,
};
let orig_scope_len = scope.len();
let context =
EvalContext::new(self, global, caches, scope, this_ptr.as_deref_mut());
let filter_result = filter(true, info, context);
if orig_scope_len != scope.len() {
// The scope is changed, always search from now on
global.always_search_scope = true;
}
if !filter_result? {
return Err(ERR::ErrorForbiddenVariable(var_name.to_string(), *pos).into());
}
}
// Evaluate initial value
let mut value = self
.eval_expr(global, caches, scope, this_ptr, expr)?
.flatten()
.intern_string(self);
let _alias = if !rewind_scope {
// Put global constants into global module
#[cfg(not(feature = "no_function"))]
#[cfg(not(feature = "no_module"))]
if global.scope_level == 0
&& access == AccessMode::ReadOnly
&& global.lib.iter().any(|m| !m.is_empty())
{
crate::func::locked_write(global.constants.get_or_insert_with(|| {
crate::Shared::new(crate::Locked::new(std::collections::BTreeMap::new()))
}))
.insert(var_name.name.clone(), value.clone());
}
if export {
Some(var_name)
} else {
None
}
} else if export {
unreachable!("exported variable not on global level");
} else {
None
};
if let Some(index) = index {
value.set_access_mode(access);
*scope.get_mut_by_index(scope.len() - index.get()) = value;
} else {
scope.push_entry(var_name.name.clone(), access, value);
}
#[cfg(not(feature = "no_module"))]
if let Some(alias) = _alias {
scope.add_alias_by_index(scope.len() - 1, alias.as_str().into());
}
return Ok(Dynamic::UNIT);
}
// Stop merging branches here!
// We shouldn't lift out too many variants because, soon or later, the added comparisons
// will cost more than the mis-predicted `match` branch.
Self::black_box();
match stmt {
// No-op
Stmt::Noop(..) => Ok(Dynamic::UNIT),
// Expression as statement
Stmt::Expr(expr) => self
.eval_expr(global, caches, scope, this_ptr, expr)
.map(Dynamic::flatten),
// Block scope
Stmt::Block(statements, ..) => {
if statements.is_empty() {
Ok(Dynamic::UNIT)
} else {
self.eval_stmt_block(global, caches, scope, this_ptr, statements, true)
}
}
// If statement
Stmt::If(x, ..) => {
let FlowControl {
expr,
body: if_block,
branch: else_block,
} = &**x;
let guard_val = self
.eval_expr(global, caches, scope, this_ptr.as_deref_mut(), expr)?
.as_bool()
.map_err(|typ| self.make_type_mismatch_err::<bool>(typ, expr.position()))?;
match guard_val {
true if !if_block.is_empty() => {
self.eval_stmt_block(global, caches, scope, this_ptr, if_block, true)
}
false if !else_block.is_empty() => {
self.eval_stmt_block(global, caches, scope, this_ptr, else_block, true)
}
_ => Ok(Dynamic::UNIT),
}
}
// Switch statement
Stmt::Switch(x, ..) => {
let (
expr,
SwitchCasesCollection {
expressions,
cases,
def_case,
ranges,
},
) = &**x;
let mut result = None;
let value = self.eval_expr(global, caches, scope, this_ptr.as_deref_mut(), expr)?;
if value.is_hashable() {
let hasher = &mut get_hasher();
value.hash(hasher);
let hash = hasher.finish();
// First check hashes
if let Some(case_blocks_list) = cases.get(&hash) {
debug_assert!(!case_blocks_list.is_empty());
for &index in case_blocks_list {
let block = &expressions[index];
let cond_result = match block.condition {
Expr::BoolConstant(b, ..) => b,
ref c => self
.eval_expr(global, caches, scope, this_ptr.as_deref_mut(), c)?
.as_bool()
.map_err(|typ| {
self.make_type_mismatch_err::<bool>(typ, c.position())
})?,
};
if cond_result {
result = Some(&block.expr);
break;
}
}
} else if !ranges.is_empty() {
// Then check integer ranges
for r in ranges.iter().filter(|r| r.contains(&value)) {
let ConditionalExpr { condition, expr } = &expressions[r.index()];
let cond_result = match condition {
Expr::BoolConstant(b, ..) => *b,
ref c => self
.eval_expr(global, caches, scope, this_ptr.as_deref_mut(), c)?
.as_bool()
.map_err(|typ| {
self.make_type_mismatch_err::<bool>(typ, c.position())
})?,
};
if cond_result {
result = Some(expr);
break;
}
}
}
}
result
.or_else(|| def_case.as_ref().map(|&index| &expressions[index].expr))
.map_or(Ok(Dynamic::UNIT), |expr| {
self.eval_expr(global, caches, scope, this_ptr, expr)
})
}
// Loop
Stmt::While(x, ..)
if matches!(x.expr, Expr::Unit(..) | Expr::BoolConstant(true, ..)) =>
{
let FlowControl { body, .. } = &**x;
if body.is_empty() {
loop {
self.track_operation(global, body.position())?;
}
}
loop {
let this_ptr = this_ptr.as_deref_mut();
match self.eval_stmt_block(global, caches, scope, this_ptr, body, true) {
Ok(..) => (),
Err(err) => match *err {
ERR::LoopBreak(false, ..) => (),
ERR::LoopBreak(true, value, ..) => break Ok(value),
_ => break Err(err),
},
}
}
}
// While loop
Stmt::While(x, ..) => {
let FlowControl { expr, body, .. } = &**x;
loop {
let condition = self
.eval_expr(global, caches, scope, this_ptr.as_deref_mut(), expr)?
.as_bool()
.map_err(|typ| self.make_type_mismatch_err::<bool>(typ, expr.position()))?;
if !condition {
break Ok(Dynamic::UNIT);
}
if body.is_empty() {
continue;
}
let this_ptr = this_ptr.as_deref_mut();
match self.eval_stmt_block(global, caches, scope, this_ptr, body, true) {
Ok(..) => (),
Err(err) => match *err {
ERR::LoopBreak(false, ..) => (),
ERR::LoopBreak(true, value, ..) => break Ok(value),
_ => break Err(err),
},
}
}
}
// Do loop
Stmt::Do(x, options, ..) => {
let FlowControl { expr, body, .. } = &**x;
let is_while = !options.contains(ASTFlags::NEGATED);
loop {
if !body.is_empty() {
let this_ptr = this_ptr.as_deref_mut();
match self.eval_stmt_block(global, caches, scope, this_ptr, body, true) {
Ok(..) => (),
Err(err) => match *err {
ERR::LoopBreak(false, ..) => continue,
ERR::LoopBreak(true, value, ..) => break Ok(value),
_ => break Err(err),
},
}
}
let condition = self
.eval_expr(global, caches, scope, this_ptr.as_deref_mut(), expr)?
.as_bool()
.map_err(|typ| self.make_type_mismatch_err::<bool>(typ, expr.position()))?;
if condition ^ is_while {
break Ok(Dynamic::UNIT);
}
}
}
// For loop
Stmt::For(x, ..) => {
let (var_name, counter, FlowControl { expr, body, .. }) = &**x;
let iter_obj = self
.eval_expr(global, caches, scope, this_ptr.as_deref_mut(), expr)?
.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 iter_func = self
.global_modules
.iter()
.find_map(|m| m.get_iter(iter_type));
#[cfg(not(feature = "no_module"))]
let iter_func = iter_func
.or_else(|| global.get_iter(iter_type))
.or_else(|| {
self.global_sub_modules
.as_deref()
.into_iter()
.flatten()
.find_map(|(_, m)| m.get_qualified_iter(iter_type))
});
let iter_func = iter_func.ok_or_else(|| ERR::ErrorFor(expr.start_position()))?;
// Restore scope at end of statement
auto_restore! { scope => rewind; let orig_scope_len = scope.len(); }
// Add the loop variables
let counter_index = (!counter.is_empty()).then(|| {
scope.push(counter.name.clone(), 0 as INT);
scope.len() - 1
});
scope.push(var_name.name.clone(), ());
let index = scope.len() - 1;
let mut result = Dynamic::UNIT;
for (x, iter_value) in iter_func(iter_obj).enumerate() {
// Increment counter
if let Some(counter_index) = counter_index {
// As the variable increments from 0, this should always work
// since any overflow will first be caught below.
let index_value = x as INT;
#[cfg(not(feature = "unchecked"))]
#[allow(clippy::absurd_extreme_comparisons)]
if index_value > crate::MAX_USIZE_INT {
return Err(ERR::ErrorArithmetic(
format!("for-loop counter overflow: {x}"),
counter.pos,
)
.into());
}
*scope.get_mut_by_index(counter_index).write_lock().unwrap() =
Dynamic::from_int(index_value);
}
// Set loop value
let value = iter_value
.map_err(|err| err.fill_position(expr.position()))?
.flatten();
*scope.get_mut_by_index(index).write_lock().unwrap() = value;
// Run block
self.track_operation(global, body.position())?;
if body.is_empty() {
continue;
}
let this_ptr = this_ptr.as_deref_mut();
match self.eval_stmt_block(global, caches, scope, this_ptr, body, true) {
Ok(_) => (),
Err(err) => match *err {
ERR::LoopBreak(false, ..) => (),
ERR::LoopBreak(true, value, ..) => {
result = value;
break;
}
_ => return Err(err),
},
}
}
Ok(result)
}
// Continue/Break statement
Stmt::BreakLoop(expr, options, pos) => {
let is_break = options.contains(ASTFlags::BREAK);
let value = if let Some(ref expr) = expr {
self.eval_expr(global, caches, scope, this_ptr, expr)?
} else {
Dynamic::UNIT
};
Err(ERR::LoopBreak(is_break, value, *pos).into())
}
// Try/Catch statement
Stmt::TryCatch(x, ..) => {
let FlowControl {
body: try_block,
expr: catch_var,
branch: catch_block,
} = &**x;
match self.eval_stmt_block(
global,
caches,
scope,
this_ptr.as_deref_mut(),
try_block,
true,
) {
r @ Ok(_) => r,
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.unwrap_inner() {
ERR::ErrorRuntime(x, ..) => x.clone(),
#[cfg(feature = "no_object")]
_ => {
let _ = err.take_position();
err.to_string().into()
}
#[cfg(not(feature = "no_object"))]
_ => {
let mut err_map = crate::Map::new();
let err_pos = err.take_position();
err_map.insert("message".into(), err.to_string().into());
if let Some(ref source) = global.source {
err_map.insert("source".into(), source.into());
}
if !err_pos.is_none() {
err_map.insert(
"line".into(),
(err_pos.line().unwrap() as INT).into(),
);
err_map.insert(
"position".into(),
(err_pos.position().unwrap_or(0) as INT).into(),
);
}
err.dump_fields(&mut err_map);
err_map.into()
}
};
// Restore scope at end of block
auto_restore! { scope if !catch_var.is_unit() => rewind; let orig_scope_len = scope.len(); }
if let Expr::Variable(x, ..) = catch_var {
scope.push(x.3.clone(), err_value);
}
let this_ptr = this_ptr.as_deref_mut();
self.eval_stmt_block(global, caches, scope, this_ptr, catch_block, true)
.map(|_| Dynamic::UNIT)
.map_err(|result_err| match *result_err {
// Re-throw exception
ERR::ErrorRuntime(v, pos) if v.is_unit() => {
err.set_position(pos);
err
}
_ => result_err,
})
}
}
}
// Throw value
Stmt::Return(Some(expr), options, pos) if options.contains(ASTFlags::BREAK) => self
.eval_expr(global, caches, scope, this_ptr, expr)
.and_then(|v| Err(ERR::ErrorRuntime(v.flatten(), *pos).into())),
// Empty throw
Stmt::Return(None, options, pos) if options.contains(ASTFlags::BREAK) => {
Err(ERR::ErrorRuntime(Dynamic::UNIT, *pos).into())
}
// Return value
Stmt::Return(Some(expr), .., pos) => self
.eval_expr(global, caches, scope, this_ptr, expr)
.and_then(|v| Err(ERR::Return(v.flatten(), *pos).into())),
// Empty return
Stmt::Return(None, .., pos) => Err(ERR::Return(Dynamic::UNIT, *pos).into()),
// Import statement
#[cfg(not(feature = "no_module"))]
Stmt::Import(x, _pos) => {
use crate::ModuleResolver;
let (expr, export) = &**x;
// Guard against too many modules
if global.num_modules_loaded >= self.max_modules() {
return Err(ERR::ErrorTooManyModules(*_pos).into());
}
let v = self.eval_expr(global, caches, scope, this_ptr, expr)?;
let typ = v.type_name();
let path = v.try_cast::<crate::ImmutableString>().ok_or_else(|| {
self.make_type_mismatch_err::<crate::ImmutableString>(typ, expr.position())
})?;
let path_pos = expr.start_position();
let resolver = global.embedded_module_resolver.clone();
let module = resolver
.as_ref()
.and_then(
|r| match r.resolve_raw(self, global, scope, &path, path_pos) {
Err(err) if matches!(*err, ERR::ErrorModuleNotFound(..)) => None,
result => Some(result),
},
)
.or_else(|| {
Some(
self.module_resolver()
.resolve_raw(self, global, scope, &path, path_pos),
)
})
.unwrap_or_else(|| {
Err(ERR::ErrorModuleNotFound(path.to_string(), path_pos).into())
})?;
let (export, must_be_indexed) = if export.is_empty() {
(self.const_empty_string(), false)
} else {
(export.name.clone(), true)
};
if !must_be_indexed || module.is_indexed() {
global.push_import(export, module);
} else {
// Index the module (making a clone copy if necessary) if it is not indexed
let mut m = crate::func::shared_take_or_clone(module);
m.build_index();
global.push_import(export, m);
}
global.num_modules_loaded += 1;
Ok(Dynamic::UNIT)
}
// Export statement
#[cfg(not(feature = "no_module"))]
Stmt::Export(x, ..) => {
use crate::ast::Ident;
let (Ident { name, pos, .. }, Ident { name: alias, .. }) = &**x;
// Mark scope variables as public
scope.search(name).map_or_else(
|| Err(ERR::ErrorVariableNotFound(name.to_string(), *pos).into()),
|index| {
let alias = if alias.is_empty() { name } else { alias }.clone();
scope.add_alias_by_index(index, alias);
Ok(Dynamic::UNIT)
},
)
}
// Share statement
#[cfg(not(feature = "no_closure"))]
Stmt::Share(x) => {
for (name, index, pos) in &**x {
if let Some(index) = index
.map(|n| scope.len() - n.get())
.or_else(|| scope.search(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();
}
} else {
return Err(ERR::ErrorVariableNotFound(name.to_string(), *pos).into());
}
}
Ok(Dynamic::UNIT)
}
_ => unreachable!("statement cannot be evaluated: {:?}", stmt),
}
}
/// Evaluate a list of statements with no `this` pointer.
/// This is commonly used to evaluate a list of statements in an [`AST`][crate::AST] or a script function body.
#[inline(always)]
pub(crate) fn eval_global_statements(
&self,
global: &mut GlobalRuntimeState,
caches: &mut Caches,
scope: &mut Scope,
statements: &[Stmt],
) -> RhaiResult {
self.eval_stmt_block(global, caches, scope, None, statements, false)
.or_else(|err| match *err {
ERR::Return(out, ..) => Ok(out),
ERR::LoopBreak(..) => {
unreachable!("no outer loop scope to break out of")
}
_ => Err(err),
})
}
}