WASM Generation

Generate WASM modules for constraint predicates

Tags:

This section covers generating WebAssembly modules for constraint predicates.

In This Section

Expressions - Build predicate expressions with the Expression API
Module Builder - Generate WASM modules with WasmModuleBuilder

Overview

Constraint predicates (filter conditions, joiners, weighers) are compiled to WebAssembly. The WASM module is sent to the solver service along with your domain model and constraints.

use solverforge_core::wasm::{
    Expr, FieldAccessExt, WasmModuleBuilder, PredicateDefinition,
    HostFunctionRegistry,
};

// Build predicate: employee assigned but missing required skill
let predicate = {
    let shift = Expr::param(0);
    let employee = shift.clone().get("Shift", "employee");
    Expr::and(
        Expr::is_not_null(employee.clone()),
        Expr::not(Expr::list_contains(
            employee.get("Employee", "skills"),
            shift.get("Shift", "requiredSkill"),
        ))
    )
};

// Build WASM module
let wasm = WasmModuleBuilder::new()
    .with_domain_model(model)
    .with_host_functions(HostFunctionRegistry::with_standard_functions())
    .add_predicate(PredicateDefinition::from_expression("skillMismatch", 1, predicate))
    .build()?;

Why WASM?

WebAssembly provides:

Portability: Same predicates work across platforms
Safety: Sandboxed execution
Performance: Near-native speed
No JNI: Clean HTTP interface instead of complex native bindings

Components

Component	Purpose
`Expression`	AST for predicate logic
`Expr`	Fluent builder for expressions
`PredicateDefinition`	Named predicate with arity
`WasmModuleBuilder`	Compiles expressions to WASM
`HostFunctionRegistry`	Registers host function imports