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feat: add and/or keywords, handle alias, --watch flag, JS tree-shaking

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- WISH-008: `and`/`or` as aliases for `&&`/`||` boolean operators
- WISH-006: `handle` as alias for `run ... with` (same AST output)
- WISH-005: `--watch` flag for `lux compile` recompiles on file change
- WISH-009: Tree-shake unused runtime sections from JS output based on
  which effects are actually used (Console, Random, Time, Http, Dom)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
Brandon Lucas
2026-02-19 03:35:47 -05:00
parent b0ccde749c
commit c67e3f31c3
4 changed files with 334 additions and 54 deletions
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277
src/codegen/js_backend.rs
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@@ -69,6 +69,8 @@ pub struct JsBackend {
has_handlers: bool,
/// Variable substitutions for let binding
var_substitutions: HashMap<String, String>,
/// Effects actually used in the program (for tree-shaking runtime)
used_effects: HashSet<String>,
}
impl JsBackend {
@@ -90,6 +92,7 @@ impl JsBackend {
effectful_functions: HashSet::new(),
has_handlers: false,
var_substitutions: HashMap::new(),
used_effects: HashSet::new(),
}
}
@@ -97,9 +100,6 @@ impl JsBackend {
pub fn generate(&mut self, program: &Program) -> Result<String, JsGenError> {
self.output.clear();
// Emit runtime helpers
self.emit_runtime();
// First pass: collect all function names, types, and effects
for decl in &program.declarations {
match decl {
@@ -116,6 +116,12 @@ impl JsBackend {
}
}
// Collect used effects for tree-shaking
self.collect_used_effects(program);
// Emit runtime helpers (tree-shaken based on used effects)
self.emit_runtime();
// Emit type constructors
for decl in &program.declarations {
if let Declaration::Type(t) = decl {
@@ -163,32 +169,181 @@ impl JsBackend {
Ok(self.output.clone())
}
/// Emit the minimal Lux runtime
/// Collect all effects used in the program for runtime tree-shaking
fn collect_used_effects(&mut self, program: &Program) {
for decl in &program.declarations {
match decl {
Declaration::Function(f) => {
for effect in &f.effects {
self.used_effects.insert(effect.name.clone());
}
self.collect_effects_from_expr(&f.body);
}
Declaration::Let(l) => {
self.collect_effects_from_expr(&l.value);
}
Declaration::Handler(h) => {
self.used_effects.insert(h.effect.name.clone());
for imp in &h.implementations {
self.collect_effects_from_expr(&imp.body);
}
}
_ => {}
}
}
}
/// Recursively collect effect names from an expression
fn collect_effects_from_expr(&mut self, expr: &Expr) {
match expr {
Expr::EffectOp { effect, args, .. } => {
self.used_effects.insert(effect.name.clone());
for arg in args {
self.collect_effects_from_expr(arg);
}
}
Expr::Run { expr, handlers, .. } => {
self.collect_effects_from_expr(expr);
for (effect, handler) in handlers {
self.used_effects.insert(effect.name.clone());
self.collect_effects_from_expr(handler);
}
}
Expr::Call { func, args, .. } => {
self.collect_effects_from_expr(func);
for arg in args {
self.collect_effects_from_expr(arg);
}
}
Expr::Lambda { body, effects, .. } => {
for effect in effects {
self.used_effects.insert(effect.name.clone());
}
self.collect_effects_from_expr(body);
}
Expr::Let { value, body, .. } => {
self.collect_effects_from_expr(value);
self.collect_effects_from_expr(body);
}
Expr::If { condition, then_branch, else_branch, .. } => {
self.collect_effects_from_expr(condition);
self.collect_effects_from_expr(then_branch);
self.collect_effects_from_expr(else_branch);
}
Expr::Match { scrutinee, arms, .. } => {
self.collect_effects_from_expr(scrutinee);
for arm in arms {
self.collect_effects_from_expr(&arm.body);
if let Some(guard) = &arm.guard {
self.collect_effects_from_expr(guard);
}
}
}
Expr::Block { statements, result, .. } => {
for stmt in statements {
match stmt {
Statement::Expr(e) => self.collect_effects_from_expr(e),
Statement::Let { value, .. } => self.collect_effects_from_expr(value),
}
}
self.collect_effects_from_expr(result);
}
Expr::BinaryOp { left, right, .. } => {
self.collect_effects_from_expr(left);
self.collect_effects_from_expr(right);
}
Expr::UnaryOp { operand, .. } => {
self.collect_effects_from_expr(operand);
}
Expr::Field { object, .. } => {
self.collect_effects_from_expr(object);
}
Expr::TupleIndex { object, .. } => {
self.collect_effects_from_expr(object);
}
Expr::Record { spread, fields, .. } => {
if let Some(s) = spread {
self.collect_effects_from_expr(s);
}
for (_, expr) in fields {
self.collect_effects_from_expr(expr);
}
}
Expr::Tuple { elements, .. } | Expr::List { elements, .. } => {
for el in elements {
self.collect_effects_from_expr(el);
}
}
Expr::Resume { value, .. } => {
self.collect_effects_from_expr(value);
}
Expr::Literal(_) | Expr::Var(_) => {}
}
}
/// Emit the Lux runtime, tree-shaken based on used effects
fn emit_runtime(&mut self) {
let uses_console = self.used_effects.contains("Console");
let uses_random = self.used_effects.contains("Random");
let uses_time = self.used_effects.contains("Time");
let uses_http = self.used_effects.contains("Http");
let uses_dom = self.used_effects.contains("Dom");
let uses_html = self.used_effects.contains("Html") || uses_dom;
self.writeln("// Lux Runtime");
self.writeln("const Lux = {");
self.indent += 1;
// Option helpers
// Core helpers — always emitted
self.writeln("Some: (value) => ({ tag: \"Some\", value }),");
self.writeln("None: () => ({ tag: \"None\" }),");
self.writeln("");
// Result helpers
self.writeln("Ok: (value) => ({ tag: \"Ok\", value }),");
self.writeln("Err: (error) => ({ tag: \"Err\", error }),");
self.writeln("");
// List helpers
self.writeln("Cons: (head, tail) => [head, ...tail],");
self.writeln("Nil: () => [],");
self.writeln("");
// Default handlers for effects
// Default handlers — only include effects that are used
self.writeln("defaultHandlers: {");
self.indent += 1;
// Console effect
if uses_console {
self.emit_console_handler();
}
if uses_random {
self.emit_random_handler();
}
if uses_time {
self.emit_time_handler();
}
if uses_http {
self.emit_http_handler();
}
if uses_dom {
self.emit_dom_handler();
}
self.indent -= 1;
self.writeln("},");
// HTML rendering — only if Html or Dom effects are used
if uses_html {
self.emit_html_helpers();
}
// TEA runtime — only if Dom is used
if uses_dom {
self.emit_tea_runtime();
}
self.indent -= 1;
self.writeln("};");
self.writeln("");
}
fn emit_console_handler(&mut self) {
self.writeln("Console: {");
self.indent += 1;
self.writeln("print: (msg) => console.log(msg),");
@@ -207,8 +362,9 @@ impl JsBackend {
self.writeln("readInt: () => parseInt(Lux.defaultHandlers.Console.readLine(), 10)");
self.indent -= 1;
self.writeln("},");
}
// Random effect
fn emit_random_handler(&mut self) {
self.writeln("Random: {");
self.indent += 1;
self.writeln("int: (min, max) => Math.floor(Math.random() * (max - min + 1)) + min,");
@@ -216,16 +372,18 @@ impl JsBackend {
self.writeln("float: () => Math.random()");
self.indent -= 1;
self.writeln("},");
}
// Time effect
fn emit_time_handler(&mut self) {
self.writeln("Time: {");
self.indent += 1;
self.writeln("now: () => Date.now(),");
self.writeln("sleep: (ms) => new Promise(resolve => setTimeout(resolve, ms))");
self.indent -= 1;
self.writeln("},");
}
// Http effect (browser/Node compatible)
fn emit_http_handler(&mut self) {
self.writeln("Http: {");
self.indent += 1;
self.writeln("get: async (url) => {");
@@ -287,8 +445,9 @@ impl JsBackend {
self.writeln("}");
self.indent -= 1;
self.writeln("},");
}
// Dom effect (browser only - stubs for Node.js)
fn emit_dom_handler(&mut self) {
self.writeln("Dom: {");
self.indent += 1;
@@ -316,7 +475,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Element creation
self.writeln("createElement: (tag) => {");
self.indent += 1;
self.writeln("if (typeof document === 'undefined') return null;");
@@ -331,7 +489,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// DOM manipulation
self.writeln("appendChild: (parent, child) => {");
self.indent += 1;
self.writeln("if (parent && child) parent.appendChild(child);");
@@ -356,7 +513,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Content
self.writeln("setTextContent: (el, text) => {");
self.indent += 1;
self.writeln("if (el) el.textContent = text;");
@@ -381,7 +537,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Attributes
self.writeln("setAttribute: (el, name, value) => {");
self.indent += 1;
self.writeln("if (el) el.setAttribute(name, value);");
@@ -408,7 +563,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Classes
self.writeln("addClass: (el, className) => {");
self.indent += 1;
self.writeln("if (el) el.classList.add(className);");
@@ -433,7 +587,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Styles
self.writeln("setStyle: (el, property, value) => {");
self.indent += 1;
self.writeln("if (el) el.style[property] = value;");
@@ -446,7 +599,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Form elements
self.writeln("getValue: (el) => {");
self.indent += 1;
self.writeln("return el ? el.value : '';");
@@ -471,7 +623,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Events
self.writeln("addEventListener: (el, event, handler) => {");
self.indent += 1;
self.writeln("if (el) el.addEventListener(event, handler);");
@@ -484,7 +635,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Focus
self.writeln("focus: (el) => {");
self.indent += 1;
self.writeln("if (el && el.focus) el.focus();");
@@ -497,7 +647,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Document
self.writeln("getBody: () => {");
self.indent += 1;
self.writeln("if (typeof document === 'undefined') return null;");
@@ -512,7 +661,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Window
self.writeln("getWindow: () => {");
self.indent += 1;
self.writeln("if (typeof window === 'undefined') return null;");
@@ -545,7 +693,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Scroll
self.writeln("scrollTo: (x, y) => {");
self.indent += 1;
self.writeln("if (typeof window !== 'undefined') window.scrollTo(x, y);");
@@ -558,7 +705,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Dimensions
self.writeln("getBoundingClientRect: (el) => {");
self.indent += 1;
self.writeln("if (!el) return { top: 0, left: 0, width: 0, height: 0, right: 0, bottom: 0 };");
@@ -574,13 +720,11 @@ impl JsBackend {
self.indent -= 1;
self.writeln("}");
self.indent -= 1;
self.writeln("}");
self.indent -= 1;
self.writeln("},");
}
// HTML rendering helpers
fn emit_html_helpers(&mut self) {
self.writeln("");
self.writeln("// HTML rendering");
self.writeln("renderHtml: (node) => {");
@@ -682,8 +826,9 @@ impl JsBackend {
self.writeln("return el;");
self.indent -= 1;
self.writeln("},");
}
// TEA (The Elm Architecture) runtime
fn emit_tea_runtime(&mut self) {
self.writeln("");
self.writeln("// The Elm Architecture (TEA) runtime");
self.writeln("app: (config) => {");
@@ -727,7 +872,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Simple app (for string-based views like the counter example)
self.writeln("");
self.writeln("// Simple TEA app (string-based view)");
self.writeln("simpleApp: (config) => {");
@@ -757,7 +901,6 @@ impl JsBackend {
self.indent -= 1;
self.writeln("},");
// Diff and patch (basic implementation for view_deps optimization)
self.writeln("");
self.writeln("// Basic diff - checks if model fields changed");
self.writeln("hasChanged: (oldModel, newModel, ...paths) => {");
@@ -777,11 +920,7 @@ impl JsBackend {
self.writeln("}");
self.writeln("return false;");
self.indent -= 1;
self.writeln("}");
self.indent -= 1;
self.writeln("};");
self.writeln("");
self.writeln("},");
}
/// Collect type information from a type declaration
@@ -3920,7 +4059,7 @@ line3"
#[test]
fn test_js_runtime_generated() {
// Test that the Lux runtime is properly generated
// Test that the Lux runtime core is always generated
use crate::parser::Parser;
let source = r#"
@@ -3931,21 +4070,51 @@ line3"
let mut backend = JsBackend::new();
let js_code = backend.generate(&program).expect("Should generate");
// Check that Lux runtime includes key functions
// Core runtime is always present
assert!(js_code.contains("const Lux = {"), "Lux object should be defined");
assert!(js_code.contains("Some:"), "Option Some should be defined");
assert!(js_code.contains("None:"), "Option None should be defined");
assert!(js_code.contains("renderHtml:"), "renderHtml should be defined");
assert!(js_code.contains("renderToDom:"), "renderToDom should be defined");
assert!(js_code.contains("escapeHtml:"), "escapeHtml should be defined");
assert!(js_code.contains("app:"), "TEA app should be defined");
assert!(js_code.contains("simpleApp:"), "simpleApp should be defined");
assert!(js_code.contains("hasChanged:"), "hasChanged should be defined");
// Console-only program should NOT include Dom, Html, or TEA sections
assert!(!js_code.contains("Dom:"), "Dom handler should not be in Console-only program");
assert!(!js_code.contains("renderHtml:"), "renderHtml should not be in Console-only program");
assert!(!js_code.contains("app:"), "TEA app should not be in Console-only program");
assert!(!js_code.contains("Http:"), "Http should not be in Console-only program");
// Console should be present
assert!(js_code.contains("Console:"), "Console handler should exist");
}
#[test]
fn test_js_runtime_tree_shaking_all_effects() {
// Test that all effects are included when all are used
use crate::parser::Parser;
let source = r#"
fn main(): Unit with {Console, Dom} = {
Console.print("Hello")
let _ = Dom.getElementById("app")
()
}
"#;
let program = Parser::parse_source(source).expect("Should parse");
let mut backend = JsBackend::new();
let js_code = backend.generate(&program).expect("Should generate");
assert!(js_code.contains("Console:"), "Console handler should exist");
assert!(js_code.contains("Dom:"), "Dom handler should exist");
assert!(js_code.contains("renderHtml:"), "renderHtml should be defined when Dom is used");
assert!(js_code.contains("renderToDom:"), "renderToDom should be defined when Dom is used");
assert!(js_code.contains("escapeHtml:"), "escapeHtml should be defined when Dom is used");
assert!(js_code.contains("app:"), "TEA app should be defined when Dom is used");
assert!(js_code.contains("simpleApp:"), "simpleApp should be defined when Dom is used");
assert!(js_code.contains("hasChanged:"), "hasChanged should be defined when Dom is used");
}
#[test]
fn test_js_runtime_default_handlers() {
// Test that default handlers are properly generated
// Test that only used effect handlers are generated
use crate::parser::Parser;
let source = r#"
@@ -3956,12 +4125,12 @@ line3"
let mut backend = JsBackend::new();
let js_code = backend.generate(&program).expect("Should generate");
// Check that default handlers include all effects
// Only Console should be present
assert!(js_code.contains("Console:"), "Console handler should exist");
assert!(js_code.contains("Random:"), "Random handler should exist");
assert!(js_code.contains("Time:"), "Time handler should exist");
assert!(js_code.contains("Http:"), "Http handler should exist");
assert!(js_code.contains("Dom:"), "Dom handler should exist");
assert!(!js_code.contains("Random:"), "Random handler should not exist in Console-only program");
assert!(!js_code.contains("Time:"), "Time handler should not exist in Console-only program");
assert!(!js_code.contains("Http:"), "Http handler should not exist in Console-only program");
assert!(!js_code.contains("Dom:"), "Dom handler should not exist in Console-only program");
}
#[test]