Module compiler

Implements all the semantics of WLambda. It takes an AST that was generated by the parser and compiles it to a tree of closures.

The compiler and the runtime require multiple other data structures, such as GlobalEnv with a SymbolTable for global functions, a ModuleResolver and a ThreadCreator.

An to execute the closures that the compiler generated you need an Env instance (which itself requires a reference to the GlobalEnv.

To orchestrate all this the EvalContext exists. You can customize:

• The GlobalEnv with custom globals and even with your own core and standard library functions
• You can provide a custom ModuleResolver, which loads the modules from other sources (eg. memory or network).
• You can make your own ThreadCreator, to customize thread creation.

However, to get some WLambda code running quickly there is EvalContext::new_default() which creates a ready made context for evaluating WLambda code:

use wlambda::*;

let mut ctx = EvalContext::new_default();
let res = ctx.eval("$[10, 20 + 30]").unwrap();

assert_eq!(res.s(), "$[10,50]");

Structs

EvalContext

This context holds all the data to compile and execute a piece of WLambda code. You can either use the default environment, or customize the EvalContext to your application’s needs. You can provide custom:

GlobalEnv

Holds global environment variables.

LocalFileModuleResolver

This structure implements the ModuleResolver trait and is responsible for loading modules on !@import for WLambda.

SymbolTable

Stores symbols and values for a WLambda module that can be added to a GlobalEnv with set_module.

Enums

EvalError

Errors that can occur when evaluating a piece of WLambda code. Usually created by methods of EvalContext.

ModuleLoadError

Error for the ModuleResolver trait, to implement custom module loading behaviour.

Traits

ModuleResolver

This trait is responsible for loading modules and returning a collection of name->value mappings for a module name.

Functions

test_eval_to_string

This is a function to help evaluating a piece of WLambda code and receive a text representation of the result. It’s primarily used by the WLambda test suite.

Type Aliases

GlobalEnvRef

Reference type of GlobalEnv.