feat: improve formatter and attribute block handling

- Format multi-line assignments with proper alignment
- Format FB calls in multiline style with parameter alignment
- Auto-expand collapsed attribute blocks before save
- Rename command from LspSCLFormat to SCLFormat
- Condense AGENTS.md and add testing section with reference project

AGENTS.md

@@ -1,6 +1,6 @@
 # AGENTS.md - SCL Language Server
 
-A unified Neovim/LazyVim plugin for Siemens SCL language support providing LSP, linting, formatting, syntax highlighting, and auto-completion.
+A Neovim/LazyVim plugin for Siemens SCL language support providing LSP, linting, formatting, syntax highlighting, and auto-completion.
 
 ## Build/Lint/Test Commands
 
@@ -12,7 +12,7 @@ lua src/main.lua --test       # Direct test execution
 
 # Tree-sitter Parser
 tree-sitter generate          # Generate parser from grammar.js
-tree-sitter test              # Run parser tests
+tree-sitter test              # Run all parser tests
 tree-sitter parse <file.scl>  # Parse single SCL file
 
 # Lua Linting
@@ -31,11 +31,10 @@ scl_lsp/
 │   ├── formatter.lua       # Document formatter
 │   ├── treesitter.lua      # Tree-sitter integration
 │   ├── plc_json.lua        # External UDT/DB loading
-│   ├── builtin_instructions.lua  # TIA Portal built-in types/FBs/functions
+│   ├── builtin_instructions.lua  # TIA Portal built-in types
 │   └── json.lua            # JSON encoder/decoder
 ├── lua/scl/                 # Neovim plugin (uses require)
 │   ├── init.lua            # Main plugin setup
-│   ├── blink_cmp_source.lua
 │   ├── udt_parser.lua      # UDT parser
 │   ├── db_parser.lua       # Global DB parser
 │   ├── fb_parser.lua       # Function Block parser
@@ -43,34 +42,26 @@ scl_lsp/
 │   ├── workspace_types.lua # Workspace scanning
 │   ├── multiline_params.lua
 │   ├── auto_prefix.lua
-│   └── attr_toggle.lua       # Interactive attribute block toggle
+│   └── attr_toggle.lua
 ├── queries/                 # Tree-sitter queries
-│   ├── highlights.scm
-│   ├── indents.scm
-│   └── folds.scm
 └── grammar.js               # Tree-sitter grammar
 ```
 
 ## Filetype Detection
 
-The LSP requires the `scl` filetype to be set. Add to your Neovim config (e.g., `ftdetect/scl.vim`):
+Required in Neovim config (ftdetect/scl.vim):
-
 ```vim
 au BufRead,BufNewFile *.scl set filetype=scl
 au BufRead,BufNewFile *.udt set filetype=scl
 au BufRead,BufNewFile *.db set filetype=scl
 ```
 
-This enables LSP features (completion, goto definition, hover, etc.) for all SCL-related file types.
-
 ## Code Style Guidelines
 
 ### Module Pattern
 ```lua
--- File header comment
 local M = {}
 
--- Private cache
 local cache = {}
 
 function M.public_function()
@@ -89,8 +80,8 @@ return M
 - Booleans: prefix with `is_`, `has_` (e.g., `is_udt`, `has_members`)
 
 ### Imports
-- `lua/scl/` modules: use `require("scl.module_name")`
+- `lua/scl/` modules: `require("scl.module_name")`
-- `src/` modules: use `dofile(script_path .. "/module.lua")`
+- `src/` modules: `dofile(script_path .. "/module.lua")`
 - External dependencies: wrap in `pcall()` for safety
 
 ### Code Formatting
@@ -99,6 +90,9 @@ return M
 - Max line length: 120 characters
 - No trailing whitespace
 
+### Comments
+**DO NOT ADD COMMENTS** in code unless explicitly requested by the user.
+
 ### Parser Module API
 All parser modules must implement:
 - `parse_*_file(filepath)` - Parse and cache
@@ -121,291 +115,54 @@ function M.clear_cache()
 end
 ```
 
-## Lua Reserved Keywords
+### Error Handling
-
-Cannot use reserved keywords as table keys directly:
-```lua
--- WRONG: syntax error
-local range = { start = pos1, end = pos2 }
-
--- CORRECT: bracket notation
-local range = { start = pos1, ["end"] = pos2 }
-```
-
-Critical for LSP range objects with `end` field.
-
-## Error Handling
-
-### Return Pattern
 ```lua
 function M.parse_file(filepath)
   local file = io.open(filepath, "r")
   if not file then
     return nil, "Cannot open file: " .. filepath
   end
-  -- ... parse logic
   return result
 end
-```
 
-### External Dependencies
+-- External dependencies
-```lua
 local ok, module = pcall(require, "some_module")
 if ok and module then
   module.do_something()
 end
 ```
 
-## Diagnostics
+## Lua Reserved Keywords
-
-The LSP validates data types and provides warnings for unknown types. It recognizes:
-- **Elementary data types** - BOOL, BYTE, WORD, DWORD, LWORD, CHAR, WCHAR, STRING, WSTRING, INT, DINT, LINT, USINT, SINT, UINT, UDINT, ULINT, REAL, LREAL, TIME, DATE, TOD, TIME_OF_DAY, DATE_AND_TIME, DT, S5TIME, LTIME, DTL
-- **Timer/counter types** - IEC_TIMER, TON_TIME, TOF_TIME, TONR_TIME, TP_TIME, CTU, CTD, CTUD
-- **TIA Portal built-in instructions** - Functions and function blocks
-- **Workspace types** - UDTs from `.udt` files and data blocks from `.db` files
-
-## Completion Triggers
-- `#` - Local variables (after BEGIN)
-- `.` - Member access (UDT/DB)
-- `"` - Global DB names
-- `(` - FB/Function parameters
-- ` ` (space) - General completion
-- `:` - Type declaration (in VAR section)
-
-### Completion Types
-The LSP provides auto-completion for:
-- **Local variables** - Variables declared in VAR sections
-- **UDT types** - User-defined types from `.udt` files
-- **Global DBs** - Data blocks from `.db` files  
-- **Elementary types** - BOOL, INT, DINT, REAL, TIME, etc.
-- **TIA Portal built-in FBs** - TON, TOF, TP, CTU, CTD, CTUD, R_TRIG, etc.
-- **TIA Portal built-in functions** - ADD, SUB, MUL, DIV, SIN, COS, SQRT, etc.
-
-## Formatter Options
-
-The formatter supports collapsing verbose attribute blocks:
 
+Cannot use reserved keywords as table keys directly:
 ```lua
--- Before formatting:
+-- WRONG
-statCntrPartsIn{EXTERNALACCESSIBLE := 'false'; EXTERNALVISIBLE := 'false'} : Int;
+local range = { start = pos1, end = pos2 }
 
--- After formatting:
+-- CORRECT
-statCntrPartsIn{...} : Int;
+local range = { start = pos1, ["end"] = pos2 }
 ```
 
-### Formatter Configuration
+Critical for LSP range objects with `end` field.
-```lua
-local options = {
-  insertSpaces = false,
-  tabSize = 1,
-  collapseAttributes = false,  -- Disabled by default (see note below)
-  collapsePatterns = {        -- Override default patterns
-    "^%s*{%s*EXTERNAL",
-    "^%s*{ S7_",
-  },
-  extendCollapsePatterns = {  -- Add custom patterns
-    "^%s*{%s*CUSTOM",
-  },
-}
-```
 
-**Note:** `collapseAttributes` is disabled by default to preserve compatibility with the interactive toggle feature (`:SCLToggleAttrBlock`). When the formatter automatically collapses blocks, the original content is lost. To use both formatting and toggle:
+## Type System
-1. Format with `:LspSCLFormat` (preserves original content)
-2. Manually collapse with `:SCLCollapseAllAttrBlocks` (stores original content)
-3. Now toggle/expand works correctly
 
-### Default Collapse Patterns
+The LSP validates data types and provides warnings for unknown types:
-The `:SCLCollapseAllAttrBlocks` command uses case-insensitive patterns:
+- **Elementary**: BOOL, BYTE, WORD, DWORD, INT, DINT, REAL, TIME, STRING, etc.
-- `EXTERNAL` - Variable attributes: `{EXTERNALACCESSIBLE := 'false'; EXTERNALVISIBLE := 'false'}`
+- **Timer/counter**: IEC_TIMER, TON_TIME, TOF_TIME, CTU, CTD, CTUD
-- `S7_` - Block attributes: `{S7_Optimized_Access := 'TRUE'}`
+- **Built-in FBs**: TON, TOF, TP, R_TRIG, F_TRIG, etc.
-- `NonRetain` - NonRetain attribute: `{NonRetain}`
+- **Built-in functions**: ADD, SUB, MUL, DIV, SIN, COS, SQRT, etc.
-- `Retain` - Retain attribute: `{Retain}`
+- **Workspace types**: UDTs from `.udt` files, DBs from `.db` files
-- `%w+ :=` - Generic attributes with assignments: `{key := 'value'}`
-- `%w+` - Single word attributes: `{SomeAttribute}`
-
-Works in `.scl`, `.udt`, and `.db` files.
-
-### Per-Variable Collapse Rules
-Control collapsing per variable using rules (evaluated before global patterns):
-
-```lua
-local options = {
-  collapseVariableRules = {
-    -- Collapse attributes for variables starting with "stat"
-    {
-      variablePattern = "^stat",
-      collapse = true,
-    },
-    -- Never collapse for "temp" prefix variables
-    {
-      variablePattern = "^temp",
-      collapse = false,
-    },
-    -- Collapse only if both variable AND attribute match
-    {
-      variablePattern = "^config",
-      attributePattern = "EXTERNAL",
-      collapse = true,
-    },
-  },
-}
-```
-
-**Rule properties:**
-- `variablePattern` - Lua pattern to match variable name (optional)
-- `attributePattern` - Lua pattern to match attribute content (optional)
-- `collapse` - `true` to collapse to `{...}`, `false` to keep expanded
-
-Rules are checked in order; first match wins.
-
-## Commands
-
-| Command | Description |
-|---------|-------------|
-| `:SCLShowVariables` | Show local variables |
-| `:SCLShowWorkspaceTypes` | Show workspace types count |
-| `:SCLRescanWorkspaceTypes` | Rescan workspace |
-| `:SCLPrefixWord` | Prefix word with `#` |
-| `:SCLMultilineParams` | Fill FB parameters |
-| `:LspSCLFormat` | Format SCL file |
-| `:SCLToggleAttrBlock` | Toggle attribute block under cursor |
-| `:SCLExpandAllAttrBlocks` | Expand all `{...}` blocks in buffer |
-| `:SCLCollapseAllAttrBlocks` | Collapse all matching attribute blocks |
-
-## LSP Features
-
-### Goto Declaration (`gD`)
-The LSP supports goto declaration functionality for:
-- **Functions** - Jump to function definition in `.scl` files
-- **Function Blocks (FB)** - Jump to FB definition in `.scl` files
-- **Data Blocks (DB)** - Jump to DB definition in `.scl` and `.db` files
-- **User-Defined Types (UDT)** - Jump to type definition in `.scl` and `.udt` files
-
-Usage: Place cursor on a variable or type name and press `gD` (or use LSP client command).
-
-## Auto-Editing Features
-
-### Auto-Uppercase Keywords
-When typing SCL keywords followed by a space, they are automatically converted to uppercase:
-- `if ` → `IF `
-- `then ` → `THEN `
-- `end_if` → `END_IF`
-- etc.
-
-Works in `.scl`, `.udt`, and `.db` files.
-
-### Auto-Semicolon for Control Structures
-When pressing Enter after an `END_*` control structure keyword, a semicolon is automatically added:
-- `END_IF` → `END_IF;`
-- `END_FOR` → `END_FOR;`
-- `END_WHILE` → `END_WHILE;`
-- `END_REPEAT` → `END_REPEAT;`
-- `END_CASE` → `END_CASE;`
-
-Block definitions (END_VAR, END_FUNCTION, etc.) are NOT affected.
-
-### Auto-Prefix Local Variables
-Local variables are automatically prefixed with `#` when typing space or semicolon after BEGIN:
-- `myVar := ` → `#myVar := `
-- `counter.in` → `#counter.in` (on dot)
-
-Can be toggled with `:lua require("scl.auto_prefix").toggle()`.
-
-## Keybindings (SCL/UDT files)
-
-### Attribute Block Toggle
-Interactive expand/collapse of individual `{...}` blocks (uses `<Leader>x` prefix):
-
-| Key | Mode | Description |
-|-----|------|-------------|
-| `<Leader>xa` | Normal/Insert | Toggle block under cursor |
-| `<Leader>xae` | Normal | Expand all collapsed blocks |
-| `<Leader>xac` | Normal | Collapse all attribute blocks |
-
-**How it works:**
-1. Place cursor inside any `{...}` block
-2. Press `<Leader>xa` to toggle between collapsed `{...}` and expanded content
-3. Original content is stored per-buffer and persists until buffer is closed
-4. Works on both formatter-collapsed blocks and manually collapsed ones
-
-### Other Keybindings
-
-| Key | Mode | Description |
-|-----|------|-------------|
-| `<Space>mp` | Insert | Fill multiline FB parameters |
-| `<Tab>` | Insert | Jump to next parameter or regular Tab |
-
-Note: `<Leader>` is typically `\` (backslash) or `<Space>` depending on your configuration.
-
-### Troubleshooting
-
-**If commands or keybindings don't work:**
-
-1. Check if setup() was called:
-   ```lua
-   :lua print(vim.inspect(require("scl_lsp")))
-   ```
-
-2. Verify commands exist:
-   ```vim
-   :command SCLToggleAttrBlock
-   ```
-   Should show the command definition.
-
-3. Check for errors during setup:
-   ```lua
-   :lua require("scl_lsp").setup({})
-   ```
-
-4. Verify leader key:
-   ```vim
-   :echo mapleader
-   ```
-   If empty, your leader is `\` (backslash).
-
-5. Manual test keybinding:
-   ```vim
-   :nmap <Leader>xa
-   ```
-   Should show the mapping.
-
-### Attribute Toggle After Formatting
-
-**Note:** After using `:LspSCLFormat`, all collapsed attribute blocks will be expanded and the toggle state is reset. This is because formatting changes line numbers and positions. You can collapse blocks again after formatting.
 
 ## Testing
 
-Manual testing using: `~/dev/siemens/projects/scl_lang_support_lazyvim_ref_project`
+Use the reference project for testing:
-
+```
-Workflow:
+~/dev/siemens/projects/scl_lang_support_lazyvim_ref_project/
-1. Open `.scl` file in Neovim
-2. Test LSP features (hover, completion, go-to-definition)
-3. Verify diagnostics
-4. Test formatting
-5. Check workspace scanning
-
-## LSP Implementation Notes
-
-### Method Name Conversion
-```lua
-local method_name = message.method:gsub("/", "_")
-local handler = handlers[method_name]
 ```
 
-### Request vs Notification
+Contains `.scl`, `.db`, `.udt`, and `.xml` files for comprehensive testing of:
-```lua
+- LSP features (hover, completion, go-to-definition)
-if message.id then
+- Formatter (`:SCLFormat`)
-  -- Request: send response
+- Attribute block toggle
-  return { id = message.id, result = result }
+- Workspace type scanning
-end
--- Notification: no response needed
-```
-
-### Script Path Pattern
-```lua
-local script_path = debug.getinfo(1, "S").source:gsub("^@", ""):match("(.*/)") or ""
-if script_path == "" then
-  script_path = "."
-end
-package.path = package.path .. ";" .. script_path .. "/?.lua"
-```

README.md

@@ -27,7 +27,9 @@ A comprehensive Neovim/LazyVim plugin providing **Language Server Protocol (LSP)
 ### Formatter
 | Feature | Description |
 |---------|-------------|
-| **Document Formatting** | Format entire SCL files |
+| **Document Formatting** | Format entire SCL files with `:SCLFormat` |
+| **Multi-line Assignments** | Preserves and formats multi-line expressions with proper alignment |
+| **FB Call Formatting** | Formats function block calls in multiline style |
 | **Indentation** | Proper block indentation |
 | **Keyword Casing** | Maintains SCL keyword casing |
 
@@ -119,8 +121,7 @@ require("scl_lsp").setup({
 | `:SCLRescanWorkspaceTypes` | Rescan workspace for types and DBs |
 | `:SCLPrefixWord` | Manually prefix current word with `#` |
 | `:SCLMultilineParams` | Fill multiline parameters for FB/Function call |
-| `:LspSCLFormat` | Format current SCL file |
+| `:SCLFormat` | Format current SCL file |
-| `:SCLGeneratePlcJson` | Generate plc.data.json from data_types/ |
 | `:SCLToggleAttrBlock` | Toggle attribute block under cursor |
 | `:SCLExpandAllAttrBlocks` | Expand all `{...}` blocks in buffer |
 | `:SCLCollapseAllAttrBlocks` | Collapse all matching attribute blocks |
@@ -159,7 +160,7 @@ statCounter{...} : Int;
 - Use `<Leader>xae` to expand all blocks in buffer
 - Use `<Leader>xac` to collapse all blocks
 
-**Note:** The formatter has automatic collapsing disabled by default to preserve compatibility with the toggle feature. Format with `:LspSCLFormat` first, then use `:SCLCollapseAllAttrBlocks` to collapse while preserving the ability to expand later.
+**Note:** Collapsed blocks are automatically expanded before saving to preserve full content on disk. Use `:SCLFormat` to format, then `:SCLCollapseAllAttrBlocks` to collapse while preserving the ability to expand later.
 
 ## External UDT Support
 

lua/scl/attr_toggle.lua

@@ -80,23 +80,24 @@ function M.toggle_attr_block()
 end
 
 -- Expand all collapsed blocks in current buffer
-function M.expand_all_attr_blocks()
+function M.expand_all_attr_blocks(opts)
+  opts = opts or {}
   local bufnr = vim.api.nvim_get_current_buf()
   local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
   local count = 0
   
   if not buffer_attr_state[bufnr] then
-    vim.notify("No collapsed blocks to expand", vim.log.levels.INFO)
+    if not opts.silent then
+      vim.notify("No collapsed blocks to expand", vim.log.levels.INFO)
+    end
     return
   end
   
   for state_key, state in pairs(buffer_attr_state[bufnr]) do
     if state.is_collapsed then
-      -- state.line_num is 1-indexed, but nvim_buf_get_lines returns 0-indexed array
       local line = lines[state.line_num]
       
       if line then
-        -- Find the collapsed {...} and replace with expanded content
         local new_line = line:sub(1, state.start_col) .. state.expanded .. line:sub(state.start_col + 4)
         lines[state.line_num] = new_line
         state.is_collapsed = false
@@ -106,7 +107,9 @@ function M.expand_all_attr_blocks()
   end
   
   vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, lines)
-  vim.notify("Expanded " .. count .. " attribute block(s)", vim.log.levels.INFO)
+  if not opts.silent and count > 0 then
+    vim.notify("Expanded " .. count .. " attribute block(s)", vim.log.levels.INFO)
+  end
 end
 
 -- Helper to make a pattern case-insensitive
@@ -193,6 +196,25 @@ end
 function M.setup()
   local augroup = vim.api.nvim_create_augroup("SCLAttrToggle", { clear = true })
   
+  vim.api.nvim_create_autocmd("BufWritePre", {
+    group = augroup,
+    pattern = { "*.scl", "*.udt", "*.db" },
+    callback = function(args)
+      if buffer_attr_state[args.buf] then
+        local has_collapsed = false
+        for _, state in pairs(buffer_attr_state[args.buf]) do
+          if state.is_collapsed then
+            has_collapsed = true
+            break
+          end
+        end
+        if has_collapsed then
+          M.expand_all_attr_blocks({ silent = true })
+        end
+      end
+    end,
+  })
+  
   vim.api.nvim_create_autocmd("BufUnload", {
     group = augroup,
     pattern = { "*.scl", "*.udt", "*.db" },

lua/scl_lsp/init.lua

@@ -34,9 +34,8 @@ function M.setup(opts)
         end
         
         if opts.lsp and opts.lsp.formatting then
-          vim.api.nvim_buf_create_user_command(b, "LspSCLFormat", function()
+          vim.api.nvim_buf_create_user_command(b, "SCLFormat", function()
             vim.lsp.buf.format({ name = "scl_lsp" })
-            -- Clear attr_toggle state since line positions may have changed
             local ok, at = pcall(require, "scl.attr_toggle")
             if ok then
               at.clear_buffer_state(vim.api.nvim_get_current_buf())
@@ -56,9 +55,8 @@ function M.setup(opts)
   })
   
   -- Create global format command (works on current buffer)
-  vim.api.nvim_create_user_command("LspSCLFormat", function()
+  vim.api.nvim_create_user_command("SCLFormat", function()
     vim.lsp.buf.format({ name = "scl_lsp" })
-    -- Clear attr_toggle state since line positions may have changed
     local ok, at = pcall(require, "scl.attr_toggle")
     if ok then
       at.clear_buffer_state(vim.api.nvim_get_current_buf())