# SCL Language Server - Unified Plugin for Siemens SCL

A comprehensive Neovim/LazyVim plugin providing **Language Server Protocol (LSP)**, **Linting**, **Formatting**, and **Syntax Highlighting** for Siemens SCL (Structured Control Language) used in Siemens TIA Portal.

## Features

### LSP (Language Server Protocol)
| Feature | Description |
|---------|-------------|
| **Hover** | Press `K` to see variable type and struct fields |
| **Completion** | `#` for variables, `.` for struct fields, `(` for functions |
| **Go to Definition** | `gd` jump to variable declaration |
| **Document Symbols** | Shows functions, variables, types |
| **Workspace Symbols** | Search across all `.scl` files with fuzzy matching |
| **Semantic Tokens** | Keywords, variables highlighted |
| **Inlay Hints** | Shows variable types after declaration |
| **External UDT** | Load types from `.plc.json` or `data_types/` folder |

### Linter (Diagnostics)
| Feature | Description |
|---------|-------------|
| **Undefined Variables** | Detects variables used without declaration |
| **Invalid # Prefix** | Detects `#` prefix in VAR sections |
| **Unknown Types** | Warns about unknown data types |
| **Type Validation** | Basic type checking |

### Formatter
| Feature | Description |
|---------|-------------|
| **Document Formatting** | Format entire SCL files |
| **Indentation** | Proper block indentation |
| **Keyword Casing** | Maintains SCL keyword casing |

### Syntax Highlighting
- Full SCL syntax support via tree-sitter
- ORGANIZATION_BLOCK, FUNCTION_BLOCK, FUNCTION definitions
- Variable declarations (VAR_INPUT, VAR_OUTPUT, VAR_IN_OUT, VAR_TEMP, etc.)
- Control structures (IF/THEN/ELSE, CASE, FOR, WHILE, REPEAT)
- Code regions and comments
- All SCL data types and operators

### Additional Features
| Feature | Description |
|---------|-------------|
| **Auto-Prefix** | Automatically adds `#` prefix to local variables (like TIA Portal) |
| **Multiline Parameters** | Fill FB/Function call parameters across multiple lines with `<Space>mp` or `:SCLMultilineParams` |
| **Tab Navigation** | Jump between parameters with `<Tab>` in insert mode |
| **Workspace UDT Scanner** | Scans project for user-defined types |
| **blink.cmp Integration** | Smart completion source for blink.cmp |

## Installation

### LazyVim
```lua
-- ~/.config/nvim/lua/plugins/scl.lua
return {
  "lazar/scl_lsp",
  ft = "scl",
  lazy = true,
  dependencies = {
    "neovim/nvim-lspconfig",
    "nvim-treesitter/nvim-treesitter",
    "saghen/blink.cmp",
  },
  config = function()
    require("scl_lsp").setup({
      -- LSP options
      lsp = {
        on_attach = function(client, bufnr)
          -- custom keymaps
        end,
      },
      cmp = true,              -- Enable blink.cmp integration
      workspace_types = true,  -- Enable workspace UDT scanning
      auto_prefix = true,      -- Enable auto-# prefixing
      debug = false,
    })
  end,
}
```

### Manual Setup
```lua
-- In your init.lua or plugin file
require("scl_lsp").setup({
  server_path = "/path/to/scl_lsp/src/main.lua",
  cmp = true,
  workspace_types = true,
  auto_prefix = true,
})
```

## Configuration Options

| Option | Type | Default | Description |
|--------|------|---------|-------------|
| `server_path` | string | `~/dev/scl_lsp/src/main.lua` | Path to LSP server |
| `lsp.on_attach` | function | `nil` | Custom LSP attach callback |
| `lsp.formatting` | boolean | `false` | Enable format command |
| `cmp` | boolean | `true` | Enable blink.cmp integration |
| `workspace_types` | boolean | `true` | Enable workspace UDT scanning |
| `auto_prefix` | boolean | `true` | Enable auto-# prefixing |
| `project_root` | string | `nil` | Custom project root |
| `library_paths` | table | `{}` | Additional library paths |
| `debug` | boolean | `false` | Enable debug logging |

## Commands

| Command | Description |
|---------|-------------|
| `:SCLShowVariables` | Show local variables in current file |
| `:SCLShowWorkspaceTypes` | Show workspace UDTs and FB count |
| `:SCLRescanWorkspaceTypes` | Rescan workspace for types |
| `:SCLPrefixWord` | Manually prefix current word with `#` |
| `:SCLMultilineParams` | Fill multiline parameters for FB/Function call |
| `:LspSCLFormat` | Format current SCL file |
| `:SCLGeneratePlcJson` | Generate plc.data.json from data_types/ |

## Keybindings

| Key | Action |
|-----|--------|
| `K` | Hover (show variable info) |
| `gd` | Go to Definition |
| `<leader>s` | Document Symbols |
| `<leader>w` | Workspace Symbols |
| `<Space>mp` | Fill multiline FB/Function parameters (insert mode) |
| `<Tab>` | Jump to next parameter (insert mode) |
| `<leader>fw` | Workspace Symbols (Telescope) |
| `<leader>ca` | Code Actions |

## External UDT Support

### Option 1: Create `.plc.json`
```json
{
  "dataTypes": [
    {
      "name": "equipmentData",
      "struct": [
        {"name": "id", "dataTypeName": "INT"},
        {"name": "status", "dataTypeName": "BOOL"},
        {"name": "temperature", "dataTypeName": "REAL"}
      ]
    }
  ]
}
```

### Option 2: Auto-scan `data_types/` folder
The LSP automatically scans for SCL files in `data_types/` folder and extracts TYPE definitions.

### Option 3: Generate `.plc.json`
```bash
lua /home/lazar/dev/scl_lsp/src/plc_json.lua --generate
```

## Project Structure

```
scl_lsp/
├── README.md                    # This file
├── package.json                 # NPM scripts (tree-sitter)
├── Makefile                     # Build commands
├── grammar.js                   # Tree-sitter grammar
├── tree-sitter.json            # Parser config
├── queries/                    # Tree-sitter queries
│   ├── highlights.scm         # Syntax highlighting
│   ├── indents.scm            # Indentation
│   ├── folds.scm              # Code folding
│   ├── locals.scm             # Variable scoping
│   └── tags.scm               # Navigation tags
├── src/                        # LSP server
│   ├── main.lua               # Main entry point
│   ├── parser.lua             # Regex-based parser
│   ├── treesitter.lua         # Tree-sitter integration
│   ├── json.lua               # JSON encoder/decoder
│   ├── plc_json.lua           # External UDT loading
│   ├── diagnostics.lua        # Linter diagnostics
│   └── formatter.lua          # Document formatter
└── lua/
    └── scl_lsp/
        ├── init.lua           # Main plugin setup
        ├── plugins/
        │   └── scl.lua        # LazyVim plugin spec
        └── scl/               # Syntax/completion modules
            ├── init.lua
            ├── auto_prefix.lua
            ├── blink_cmp_source.lua
            ├── fb_parser.lua
            ├── udt_parser.lua
            ├── variables.lua
            └── workspace_types.lua
```

## Building Tree-sitter Parser

```bash
# Generate parser from grammar.js
npm run build
# or: tree-sitter generate

# Run tests
npm test
# or: tree-sitter test
```

## SCL Code Example

```pascal
FUNCTION_BLOCK "Em101Sequence"
VAR
    x : INT;
    myVar : equipmentData;  // User-defined type
END_VAR

IF x > 5 THEN
    myVar.id := 10;
END_IF

myVar.status := TRUE;
myVar.temperature := 25.5;

END_FUNCTION_BLOCK
```

## Requirements

- **Neovim 0.9+**
- **nvim-lspconfig** - LSP client
- **nvim-treesitter** - Syntax highlighting
- **blink.cmp** - Optional, for completion
- **Lua 5.1+** - LSP server runtime