STruC++ Structured Text Compiler

IEC 61131-3 Structured Text to C++17 compiler with full language support for VSCode.

STruC++ compiles Structured Text programs into clean C++17 code, targeting the OpenPLC runtime. This extension brings the compiler directly into your editor with real-time diagnostics, intelligent code completion, source-level debugging, and more.

Features

Syntax Highlighting

Full TextMate grammar and semantic token support for Structured Text, including all IEC 61131-3 keywords, types, literals, and operators.

Real-Time Diagnostics

Errors and warnings appear as you type. The compiler runs in the background, highlighting parse errors, type mismatches, undeclared variables, and more — directly in your editor.

Autocomplete & Signature Help

• Context-aware keyword and snippet completion
• Variable, function, and type completion from the current scope
• Dot-triggered member completion for function blocks and structs
• Parameter hints for function and function block calls
• Full IEC standard function library with signatures

Go to Definition & Find References

• F12 jumps to the declaration of any variable, function, function block, type, or method
• Shift+F12 finds all references across your project
• F2 renames symbols across all files
• Breadcrumb navigation shows your current scope

Document Symbols & Hover

• Outline panel shows all programs, function blocks, functions, types, and methods
• Hover over any symbol to see its type, scope, and declaration info
• Standard library functions show full parameter documentation

Code Actions & Formatting

• Quick fixes for common errors (declare variable, add missing semicolon, add type conversion)
• Document formatting with configurable indentation and keyword casing

Compile & Build

• Compile Structured Text to C++ directly from the editor
• Build standalone executables with the integrated REPL
• Build and Run to launch your program immediately
• Task provider for tasks.json integration
• Configurable compiler paths and flags

Library Support

• Bundled IEC standard function block library (TON, TOF, TP, CTU, CTD, R_TRIG, F_TRIG, SR, RS)
• Bundled OSCAT Basic library
• Automatic discovery of .stlib libraries in your workspace
• Library Explorer panel in the sidebar
• Configurable additional library paths

Source-Level Debugging

• F5 builds with debug symbols and launches the debugger
• Set breakpoints directly in .st files
• Step over, step into, step out through Structured Text source lines
• Variable inspection with IEC type display
• Force and unforce variables during debug sessions
• Works with GDB (Linux) and LLDB (macOS) via CodeLLDB or C/C++ extensions

Test Explorer Integration

• Discover and run TEST / ASSERT_* / MOCK_* test blocks from the Test Explorer
• Inline pass/fail results with gutter icons
• Failure annotations at the exact ASSERT_* line that failed
• Diff view for ASSERT_EQ failures
• Watch mode for automatic re-run on file changes

Requirements

• VSCode 1.82 or later
• g++ with C++17 support (for Build commands)
• C/C++ (Microsoft) or CodeLLDB extension (for debugging)

Extension Settings

Commands

All commands are available from the Command Palette (Cmd+Shift+P / Ctrl+Shift+P):

• STruC++: Compile Current File to C++
• STruC++: Compile Workspace to C++
• STruC++: Build Executable (REPL)
• STruC++: Build and Run REPL
• STruC++: Build and Run (Cyclic)
• STruC++: Debug Program
• STruC++: Compile Library (.stlib)
• STruC++: Run Tests
• STruC++: Force Variable / Unforce Variable / Unforce All

Links

• Autonomy — Industrial automation software
• Source Code
• Report Issues

License

GPL-3.0-or-later