> Agent-readable docs index: /llms.txt. Download /docs.zip to grep all markdown files locally. --- $schema: https://holocron.so/frontmatter.json title: RoboC++ Studio description: Browser IDE for IEC 61131-3 projects. Edit PLC source, check errors, simulate scans, and preview generated C. icon: lucide:layout-panel-left --- **RoboC++ Studio** is a browser-hosted IDE prototype in the compiler repository under **`ide/web`**. It wraps the same compiler pipeline as the **`rbcpp` CLI** through a Rust/WASM **language service**, with a React shell for editing, diagnostics, simulation traces, and generated C preview. ## What Studio provides | Area | Status | | ----------------------------------------------------------------------------------- | ------------------------------- | | Text editing for `.st`, `.il`, `.sfc`, `.ld`, `.fbd`, `.xml` | Supported | | Check, simulate, build C, compliance review | Supported (toolbar + shortcuts) | | Diagnostics table with `RBCPP-*` codes | Supported | | Symbol inspector, completions list, hover cards | Supported | | Scan trace, watches, access-path values, SFC active steps | Supported | | PLCopen import and export | Supported | | Read-only LD/FBD/SFC diagram previews with scan energization | Supported | | Partial graphical toolbar edits (append rungs/networks, NOT/SET/RESET, FBD connect) | Partial | | Target bridge (Simulator / Modbus TCP via `rbcpp-target-bridge`) | Partial | | Cloud-hosted Studio URL | Not shipped (run locally today) | Projects are stored in **browser `localStorage`**. A built-in **PackagingLine** sample workspace ships with counter, ladder, SFC, FBD, PLCopen XML, and a `target/mapping.toml` stub. ## Shell layout Studio is a single-page app with resizable panels: * **Explorer:** searchable file tree with rename, delete, drag-and-drop reorder, and new-file templates. * **Editor:** syntax-highlighted source editor; LD/FBD/SFC and PLCopen XML also show a diagram card above the text. * **Inspector:** symbols, completions, hover details, and target mapping fields. * **Bottom panels:** Diagnostics, Scan Trace, Generated C, and Output log (command history with timestamps). * **Settings:** compiler profile, cycle time, selected program/configuration, watch list, generated C output path, target bridge URL, and workspace root. * **Target connection bar:** connect to **Simulator** or **Hardware** (Modbus TCP) through the local **`rbcpp-target-bridge`** HTTP service; refresh I/O, deploy, run, stop, and reset when connected. ## Commands and shortcuts | Action | Shortcut | Backend | | ----------------------- | -------------- | ------------------------------------------------------ | | Check | **F7** | `analyze_document_json` | | Run / simulate | **F5** | `debug_document_json` | | Compliance review | **Shift+F7** | compliance profile note | | Build C | toolbar | `generated_c_artifact_json` | | Import / export PLCopen | toolbar | PLCopen I/O helpers | | Deploy package | toolbar | JSON download, or POST to target bridge when connected | | Save project | **Cmd/Ctrl+S** | `localStorage` | When the WASM language-service package is missing, Studio falls back to a **local TypeScript analysis stub** so UI development still works. Run **`npm run wasm:build`** in `ide/web` for real compiler results. ## Language service layer Studio does not call `rbcpp_cli` directly. It uses: * **`iec_language_service`**: workspace analysis, symbols, completions, hover, graph models, simulation, debug traces, generated C metadata, refactor plans, and capabilities. * **`iec_language_service_wasm`**: JSON WASM bindings consumed by the web shell. See [Architecture](/architecture#language-service-and-studio) for how these crates sit in the pipeline. ## Graphical editing status LD, FBD, and SFC canvases are **read-first** with scan-trace energization. Toolbar actions can append rungs or networks, toggle NOT contacts, SET/RESET coils, and connect FBD outputs. Full power-flow LD editing, formal FBD pin wiring, SFC divergence/convergence, and PLCopen geometry round-trip remain open work. ## Deployment and target bridge Studio builds a **deploy package** after **Build C** and a valid **`target/mapping.toml`**. The package includes source file names, parsed mapping, generated C metadata, and adapter hook stubs. * **Offline:** download the JSON package to disk. * **Connected:** when **`rbcpp-target-bridge`** is running, Studio can POST the package to **`/api/v1/deploy`**, refresh I/O through **`/api/v1/io`**, and send run/stop/reset through **`/api/v1/session/control`**. The bridge defaults to **`http://127.0.0.1:8787`**. It supports file-backed **Simulator** I/O and **Modbus TCP hardware** targets. This is integration scaffolding, not a certified online-change runtime. See [Targets and Generated C](/targets) and [Studio getting started](/studio-getting-started#optional-target-bridge). ## Related * [Getting started with Studio](/studio-getting-started): install, WASM build, verification * [CLI reference](/cli): equivalent terminal commands * [Diagnostics](/diagnostics): stable `RBCPP-*` codes Studio surfaces * [Native LD and FBD](/native-ld-fbd): textual ladder and FBD syntax in the editor * [PLCopen](/plcopen): XML import/export from Studio --- *Powered by [holocron.so](https://holocron.so)*