lux/website/lux-site/LUX_WEAKNESSES.md

# Lux Weaknesses Discovered During Website Development

This document tracks issues and limitations discovered while building the Lux website in Lux.

## Fixed Issues

### 1. Module Import System Not Working (FIXED)

**Description:** The `import` statement wasn't working for importing standard library modules.

**Root Cause:** Two issues were found:
1. Parser didn't skip newlines inside list expressions, causing parse errors in multi-line lists
2. Functions in stdlib modules weren't marked as `pub` (public), so they weren't exported

**Fix:**
1. Added `skip_newlines()` calls to `parse_list_expr()` in parser.rs
2. Added `pub` keyword to all exported functions in stdlib/html.lux

**Status:** FIXED

---

### 2. Parse Error in html.lux (FIXED)

**Description:** When trying to load files that import the html module, there was a parse error at line 196-197.

**Error Message:**
```
Module error: Module error in '<main>': Parse error: Parse error at 196-197: Unexpected token: \n
```

**Root Cause:** The parser's `parse_list_expr()` function didn't handle newlines between list elements.

**Fix:** Added `skip_newlines()` calls after `[`, after each element, and after commas in list expressions.

**Status:** FIXED

---

### 3. List.foldl Renamed to List.fold (FIXED)

**Description:** The html.lux file used `List.foldl` but the built-in List module exports `List.fold`.

**Fix:** Changed `List.foldl` to `List.fold` in stdlib/html.lux.

**Status:** FIXED

---

## Minor Issues

### 4. String.replace Verified Working

**Description:** The `escapeHtml` function in html.lux uses `String.replace`.

**Status:** VERIFIED WORKING - String.replace is implemented in the interpreter.

---

### 5. FileSystem Effect Not Fully Implemented

**Description:** For static site generation, we need `FileSystem.mkdir`, `FileSystem.write`, `FileSystem.copy` operations. These may not be fully implemented.

**Workaround:** Use Bash commands via scripts.

**Status:** Needs verification

---

### 6. List.concat Verified Working

**Description:** The `List.concat` function is used in html.lux document generation.

**Status:** VERIFIED WORKING - List.concat is implemented in the interpreter.

---

## Feature Gaps

### 7. No Built-in Static Site Generation

**Description:** There's no built-in way to generate static HTML files from Lux. A static site generator effect or module would be helpful.

**Recommendation:** Add a `FileSystem` effect with:
- `mkdir(path: String): Unit`
- `write(path: String, content: String): Unit`
- `copy(src: String, dst: String): Unit`
- `readDir(path: String): List<String>`

---

### 8. No Template String Support

**Description:** Multi-line strings and template literals (like JavaScript's backticks) would make HTML generation much easier.

**Current Approach:**
```lux
let html = "<div class=\"" + className + "\">" + content + "</div>"
```

**Better Approach (not available):**
```lux
let html = `<div class="${className}">${content}</div>`
```

**Status:** Feature request

---

### 9. No Markdown Parser

**Description:** A built-in Markdown parser would be valuable for documentation sites.

**Status:** Feature request

---

## Working Features

These features work correctly and can be used for website generation:

1. **String concatenation** - Works with `+` operator
2. **Conditional expressions** - `if/then/else` works
3. **Console output** - `Console.print()` works
4. **Basic types** - `String`, `Int`, `Bool` work
5. **Let bindings** - Variable assignment works
6. **Functions** - Function definitions work
7. **Module imports** - Works with `import stdlib/module`
8. **Html module** - Fully functional for generating HTML strings

---

## Recommendations

### For Website MVP

The module system now works! The website can be:
1. **Generated from Lux** using the html module for HTML rendering
2. **CSS separate file** (already done in `static/style.css`)
3. **Lux code examples** embedded as text in HTML

### For Future

1. **Add FileSystem effect** for writing generated HTML to files
2. **Markdown-based documentation** parsed and rendered by Lux
3. **Live playground** using WASM compilation

---

## Test Results

| Feature | Status | Notes |
|---------|--------|-------|
| String concatenation | Works | `"<" + tag + ">"` |
| Conditionals | Works | `if x then y else z` |
| Console.print | Works | Basic output |
| Module imports | Works | `import stdlib/html` |
| Html module | Works | Full HTML generation |
| List.fold | Works | Fold over lists |
| List.concat | Works | Concatenate list of lists |
| String.replace | Works | String replacement |
| FileSystem | Unknown | Not tested |

---

## Date Log

| Date | Finding |
|------|---------|
| 2026-02-16 | Module import system not working, parse error at line 196-197 in html.lux |
| 2026-02-16 | Fixed: Parser newline handling in list expressions |
| 2026-02-16 | Fixed: Added `pub` to stdlib/html.lux exports |
| 2026-02-16 | Fixed: Changed List.foldl to List.fold |