Engine Configuration Options
A number of other configuration options are available from the Engine to fine-tune behavior and safeguards.
Compile-Time Language Features
| Method | Description | Default |
|---|---|---|
set_optimization_level(not available under no_optimize) | sets the amount of script optimizations performed (see script optimization) | Simple |
set_allow_if_expression | allows/disallows if-expressions | allow |
set_allow_switch_expression | allows/disallows switch expressions | allow |
set_allow_loop_expressions | allows/disallows loop expressions | allow |
set_allow_statement_expression | allows/disallows statement expressions | allow |
set_allow_anonymous_fn(not available under no_function) | allows/disallows anonymous functions | allow |
set_allow_looping | allows/disallows looping (i.e. while, loop, do and for statements) | allow |
set_allow_shadowing | allows/disallows shadowing of variables | allow |
set_strict_variables | enables/disables Strict Variables mode | disabled |
set_fast_operators | enables/disables Fast Operators mode | enabled |
disable_symbol | disables a certain keyword or operator (see disable keywords and operators) |
Beware that these options activate during compile-time only. If an AST is compiled on an
Engine but then evaluated on a different Engine with different configuration, disallowed
features contained inside the AST will still run as normal.
Runtime Behavior
| Method | Description |
|---|---|
set_fail_on_invalid_map_property(not available under no_object) | sets whether to raise errors (instead of returning ()) when invalid properties are accessed on object maps |
set_default_tag | sets the default value of the custom state (which can be obtained via NativeCallContext::tag) for each evaluation run |
Safety Limits
| Method | Not available under | Description |
|---|---|---|
set_max_expr_depths | unchecked | sets the maximum nesting levels of an expression/statement (see maximum statement depth) |
set_max_call_levels | unchecked, no_function | sets the maximum number of function call levels (default 50) to avoid infinite recursion (see maximum call stack depth) |
set_max_operations | unchecked | sets the maximum number of operations that a script is allowed to consume (see maximum number of operations) |
set_max_variables | unchecked | sets the maximum number of variables that a script is allowed to define within a single Scope (see maximum number of variables) |
set_max_functions | unchecked, no_function | sets the maximum number of functions that a script is allowed to define (see maximum number of functions) |
set_max_modules | unchecked, [no_modules] | sets the maximum number of modules that a script is allowed to load (see maximum number of modules) |
set_max_string_size | unchecked | sets the maximum length (in UTF-8 bytes) for strings (see maximum length of strings) |
set_max_array_size | unchecked, no_index | sets the maximum size for arrays (see maximum size of arrays) |
set_max_map_size | unchecked, no_object | sets the maximum number of properties for object maps (see maximum size of object maps) |
set_max_strings_interned | sets the maximum number of strings to be interned (if zero, the strings interner is disabled) |