Struct Engine 

pub struct Engine<T: ModuleResolver = DefaultModuleResolver> { /* private fields */ }

The main execution engine for the mq.

The Engine manages parsing, optimization, and evaluation of mq code. It provides methods for configuration, loading modules, and evaluating code.

Examples

use mq_lang::DefaultEngine;

let mut engine = DefaultEngine::default();
engine.load_builtin_module();

let input = mq_lang::parse_text_input("hello").unwrap();
let result = engine.eval("add(\" world\")", input.into_iter());
assert_eq!(result.unwrap(), vec!["hello world".to_string().into()].into());

Implementations

impl<T: ModuleResolver> Engine<T>

pub fn new(module_resolver: T) -> Self

pub fn set_optimization_level(&mut self, level: OptimizationLevel)

Set the optimization level for AST transformations applied before evaluation.

pub fn set_max_call_stack_depth(&mut self, max_call_stack_depth: u32)

Set the maximum call stack depth for function calls.

This prevents infinite recursion by limiting how deep function calls can be nested. Useful for controlling resource usage.

pub fn set_search_paths(&mut self, paths: Vec<PathBuf>)

Set search paths for module loading.

These paths will be searched when loading external modules via the include statement in mq code.

pub fn define_string_value(&self, name: &str, value: &str)

Define a string variable that can be used in mq code.

This allows you to inject values from the host environment into the mq execution context.

pub fn define_value(&self, name: &str, value: RuntimeValue)

Defines an arbitrary runtime value in the current environment.

pub fn load_builtin_module(&mut self)

Load the built-in function modules.

This must be called to enable access to standard functions like add, sub, map, filter, etc.

pub fn import_module(&mut self, module_name: &str) -> Result<(), Box<Error>>

Import an external module by name.

The module will be searched for in the configured search paths and made available for use in mq code.

pub fn load_module(&mut self, module_name: &str) -> Result<(), Box<Error>>

Load an external module by name.

The module will be searched for in the configured search paths and made available for use in mq code.

pub fn eval<I: Iterator<Item = RuntimeValue>>( &mut self, code: &str, input: I, ) -> MqResult

The main engine for evaluating mq code.

The Engine manages parsing, optimization, and evaluation of mq. It provides methods for configuration, loading modules, and evaluating code.

Examples

let mut engine = mq_lang::DefaultEngine::default();
engine.load_builtin_module();

let input = mq_lang::parse_text_input("hello").unwrap();
let result = engine.eval("add(\" world\")", input.into_iter());
assert_eq!(result.unwrap(), vec!["hello world".to_string().into()].into());

pub fn compile(&mut self, code: &str) -> Result<CompiledProgram, Box<Error>>

Compiles mq code into a CompiledProgram that can be evaluated multiple times.

Use this with eval_compiled to avoid re-parsing the same query for each input.

pub fn eval_compiled<I: Iterator<Item = RuntimeValue>>( &mut self, compiled: &CompiledProgram, input: I, ) -> MqResult

Evaluates a pre-compiled program against the given input.

Use with compile to avoid re-parsing the same query for each input file, or with a CompiledProgram constructed from a deserialized JSON AST (ast-json feature).

Examples

let mut engine = mq_lang::DefaultEngine::default();
engine.load_builtin_module();

let compiled = engine.compile("add(\" world\")").unwrap();
let input = mq_lang::parse_text_input("hello").unwrap();
let result = engine.eval_compiled(&compiled, input.into_iter());
assert_eq!(result.unwrap(), vec!["hello world".to_string().into()].into());

pub const fn version() -> &'static str

Trait Implementations

impl<T: Clone + ModuleResolver> Clone for Engine<T>

fn clone(&self) -> Engine<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug + ModuleResolver> Debug for Engine<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: ModuleResolver> Default for Engine<T>

fn default() -> Self

Returns the “default value” for a type.