Clarion Extension for Visual Studio Code

Professional Clarion language support for Visual Studio Code with intelligent code navigation, IntelliSense, and build integration.

🚀 Quick Links

• 5-Minute Quick Start - Get up and running fast
• Common Tasks - Everyday workflows made easy
• Installation Guide - Detailed setup instructions
• Full Changelog - See what's new
• Report Issues - Found a bug?

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✨ Key Features

🎨 Clarion & Template Language Support

Full language support for Clarion code, basic support for templates.

• Clarion files (.clw, .inc) - Complete syntax highlighting and IntelliSense
• Template files (.tpl, .tpw) - Syntax highlighting with 100+ template keywords
• Code folding for structures and template blocks
• Context-aware coloring for Clarion code
• Note: Template files have syntax highlighting only (no IntelliSense/navigation)
• Learn more about Code Editing →

💡 Signature Help & Documentation

Get instant parameter hints and documentation - works immediately, no solution needed!

• 310 built-in functions with parameter hints and descriptions
• Method overload support — overloads narrowed by argument type (e.g. OPEN(Window) shows only WINDOW signatures)
• Hover documentation for all symbols — procedures, classes, variables, attributes, built-ins
• Context-aware hover — HIDE, DISABLE, TYPE show attribute or statement usage depending on context
• Hover for PROP:/PROPPRINT: runtime properties — descriptions from Clarion 11.1 docs
• Hover for EVENT: equates — category, description, and usage example
• Signature help for class methods including inherited members
• Learn more about Signature Help →

🤖 IntelliSense — Smart Completions

Type SELF. or MyVar. for context-aware member suggestions. Type PROP:, PROPPRINT:, or EVENT: for documented equate completions.

• Resolves SELF., PARENT., MyVar., or ClassName. to the correct class
• Full inheritance walk — shows methods and properties from parent classes
• Access control aware — PRIVATE / PROTECTED / PUBLIC scoping enforced
• Each overload shown as a distinct entry with parameter signatures
• Chained expressions (SELF.Order.) resolve intermediate types
• PROP:/PROPPRINT: completions with description and read-only badge
• EVENT: completions with category label (Field-Specific / Field-Independent / DDE)
• Learn more about Navigation →

✏️ Code Snippets

Write code faster with 50+ smart snippets - works immediately!

• Structure templates (IF, LOOP, CASE, etc.)
• Variable declaration shortcuts
• Procedure and method templates
• Learn more about Snippets →

📂 Solution Management

Open any Clarion solution - just open the folder.

• Auto-detects .sln files in folder
• Recent solutions list for quick access
• No workspace files needed
• Learn more about Solution Management →

🧭 Smart Code Navigation

Jump to definitions, find implementations, and explore references — works in same file immediately, cross-file with solution.

• Press F12 to go to definition (same file: no solution needed!)
• Press Ctrl+F12 to go to implementation
• Press Shift+F12 for Find All References — scope-aware across all project files, overload-aware (only the matching overload's sites), routine-aware
• Press F2 to Rename Symbol — renames across the entire workspace in one step
• Reference-count CodeLens — an exact N references count above every procedure, method, class, and routine; click to see them (large solutions briefly show a ~ estimate while the exact count computes)
• Routines are first-class symbols — hover, F12, Go-to-Implementation, references, and CodeLens all work on ROUTINE labels and DO sites, including generated :: names like Menu::MENUBAR1
• Module-callout procedures — references from an implementation reach every module whose MAP includes the callout INC (the generated MODULE('impl.clw') + INCLUDE pattern)
• Overload resolution by argument types — F12, Ctrl+F12, hover, and references pick the overload matching the call's arguments (typed variables, members, EQUATEs, implicit variables, PRE:Field arguments)
• Document Highlight — scope-aware occurrence highlighting, including procedure call sites
• Workspace Symbol Search (Ctrl+T) — search for any procedure, class, or label across all solution files
• Hover for documentation — declaration location, class/interface context, type info, resolved INCLUDE/MODULE/MEMBER file paths
• Chained navigation: SELF.Order.RangeList.Init — hover, F12, Ctrl+F12, and references resolve through CLASS, QUEUE, and GROUP type chains
• SELF/PARENT properties: F12 on SELF.List navigates to the class member declaration
• Typed variable members: F12/Ctrl+F12/hover on obj.Method() where obj is any typed variable
• INTERFACE support: hover, F12, Ctrl+F12, and references for interface methods, IMPLEMENTS(), and 3-part Class.Interface.Method implementations
• CLASS type names: F12 and Find All References work on type names in parameter and variable declarations
• Cross-file navigation requires solution
• Learn more about Navigation →

🔁 Refactoring & Quick Fixes

CodeRush-inspired refactors on Ctrl+. — plus quick fixes attached to diagnostics.

• Surround With… — wrap selected statements in IF…END, LOOP/LOOP WHILE/LOOP UNTIL…END, or CASE…OF…END
• Negate Condition — flip the logical sense of an IF / ELSIF / LOOP WHILE / LOOP UNTIL condition
• Flip IF/ELSE — negate the condition and swap the branches of a block-form IF…ELSE…END
• Introduce EQUATE — extract a magic literal to a named EQUATE, choosing which data section it lives in (routine / local / module / global — even cross-file into the PROGRAM)
• Create routine from DO — an unresolved DO SomeRoutine offers to scaffold the ROUTINE skeleton in the right scope
• Add missing INCLUDE / project DefineConstants — quick fixes on the corresponding diagnostics
• Learn more about Code Editing →

🔧 Build Integration

Generate applications directly from VS Code.

• Right-click to build from Solution View
• Multiple build configurations (Debug/Release) — active config auto-detected from .sln.cache
• Projects sorted by build order (dependency-first) in Solution View
• Live build output
• Learn more about Building →

🎯 Real-time Diagnostics

Catch errors as you type.

• Unterminated structures — including window sub-structures (WINDOW, SHEET, TAB, OLE, MENU, etc.)
• Missing RETURN statements
• FILE validation (DRIVER, RECORD)
• Missing INCLUDE — warns when a variable's class type is defined in an .inc not included in the file; code action inserts the INCLUDE automatically
• Missing DefineConstants — warns when a class's required Link()/DLL() constants are absent from the .cwproj; code action adds them with a QuickPick for static vs DLL mode
• Discarded return values — a value-returning (non-PROC) procedure or method called as a statement, including SELF./PARENT. call sites
• Literal passed by reference — a literal handed to a *TYPE (or complex-type) parameter, which needs an addressable variable
• Undeclared variables (opt-out) — names that resolve to no declaration through the full scope model, cross-file aware
• Missing implementations / indistinguishable prototypes — MAP declarations without bodies, and overloads a call could never disambiguate
• Character-set validation that respects all Windows ANSI code pages (1250–1258) — national letters pass clean, genuine contamination (emoji, box-drawing) is flagged
• Code inside unconditional OMIT blocks is excluded from diagnostics and reference counts (rename still updates it — other build configurations may compile it)
• Learn more about Diagnostics →

⚡ Performance at Scale

Built and measured against real-world solutions (40 projects / 3,000+ source files).

• Solution ready in ~2s, extension interactive in ~5s on large solutions
• All indexes (structure declarations, file relationships, reference counts) persist across sessions — warm starts re-scan only files that changed
• Background indexing is time-sliced and never blocks typing, hover, or navigation
• Project-file regeneration (all .cwproj files touched) coalesces into a single refresh
• Opt-in performance tracing (clarion.log.performance.enabled) produces a full diagnostic timeline for support

✏️ Code Editing Tools

Productivity features to write code faster.

• 50+ code snippets
• Paste as Clarion String
• Add Method Implementation
• Create New Class wizard
• Learn more about Code Editing →

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📦 Installation

Requirements

• Visual Studio Code (latest version)
• Clarion (for build features)

Quick Install

1. Open VS Code
2. Press Ctrl+Shift+X
3. Search for "Clarion Extensions"
4. Click Install

Detailed installation instructions →

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🎓 Learning Resources

For New Users

• Quick Start Guide - 5 minutes to your first solution
• Common Tasks - How do I...?
• Installation Guide - Detailed setup

Feature Documentation

• Navigation Features - F12, Ctrl+F12, hover tooltips
• Signature Help - Parameter hints and documentation
• Solution Management - Working with solutions
• Diagnostics & Validation - Error detection
• Code Editing Tools - Snippets, commands, wizards

Reference

• All Commands - Complete command reference
• All Settings - Configuration options
• Snippet Reference - Code snippet cheat sheet
• Clarion Language Reference - Language syntax (wiki)

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🧪 Related

The ANTLR4 grammar / folding-provider exploration (2025–Jan 2026) was split out to the archived repo Clarion-ANTLR-Grammar; tag antlr-experiment marks the last commit here that carried antlr-grammar/.

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🆕 What's New

Latest: v1.0.2 (2026-09-06) — Solutions that load wrong now say so, and a batch of navigation fixes

1.0.2 is a correctness release. The theme running through it is silent failure: several ways a solution could load in a degraded state — wrong build configuration, unresolvable redirection paths, source files missing from the index — looked identical to a healthy load, so features simply returned nothing and the extension read as broken rather than misconfigured. Those now report themselves. Alongside that is a run of hover, navigation and diagnostic fixes, many contributed by @geircodes.

• Degraded solutions are visible: source files that fail to resolve are counted and named instead of being silently dropped from the file-relationship graph; redirection macros that expand to nothing say so rather than leaving a dead search path; re-opening a solution from the recent list now validates the stored build configuration instead of adopting a stale one.
• Redirection: %THISDIR%, %WinUserApplicationData% and %WinCommonApplicationData% are implemented — previously they were left in the path as literal text, so every directory on that line failed to resolve.
• Command Palette: every command now carries a Clarion category, so typing "clarion" finds them — including how to open a solution, which was previously reachable only from the Clarion Tools sidebar.
• Navigation & hover: a bare local CLASS used as its own instance now resolves for hover, F12, Ctrl+F12, completion and signature help; colon-bearing labels no longer truncate and kill navigation; a local CLASS's indented END no longer swallows the next procedure; GROUP/QUEUE/CLASS field declarations resolve to themselves; 61 built-ins that hovered as "undefined" now show their signatures.
• Diagnostics: attribute and built-in names that collide with your own variables no longer hijack the hover card or the warning; discarded-return warnings survive a trailing comment; false "missing END" on a WINDOW with a continuation-line attribute is fixed.
• Performance: hovering an undeclared bare word in a large generated module no longer freezes for ~10s (10.5s → 13ms on the 40-project test solution), and Clarion's predefined compiler flags (DLL_MODE, _DEBUG_, _USTRING_, …) now hover properly instead of being flagged as undeclared.

See the full changelog for the complete list →

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Recent: v1.0.1 (2026-08-09) — Maintenance: performance follow-ups & correctness fixes

A stability release on top of the 1.0 overhaul — more startup and hover performance work verified on the real 40-project / 3,000-file solution, plus a batch of hover, completion, and diagnostic correctness fixes. Startup validators stopped freezing the editor in multi-second blocks, F12 on a built-in became instant instead of a ~24s cold walk, and .app global data stopped being falsely flagged "not declared" in generated MEMBER modules.

Recent: v1.0.0 (2026-07-11) — Performance at scale, exact references, refactoring

The 1.0 release was the largest update yet — a ground-up performance overhaul verified on real 40-project / 3,000-file solutions: the IDE is usable seconds after opening a large solution, with all indexes persisted across sessions and no event-loop freezes. It also brought exact reference counts with routine lenses, overload-aware navigation everywhere (FAR, F12, Ctrl+F12, hover, signature help), new refactors (Surround With, Negate Condition, Flip IF/ELSE, Introduce EQUATE, Create routine from DO), new diagnostics, and an upgrade to LSP 8.x.

See full changelog →

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💬 Support & Feedback

• GitHub Issues - Report bugs or request features
• Discussions - Ask questions, share tips

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📄 License

MIT License

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🙏 Acknowledgments

Special thanks to:

• fushnisoft - Original Clarion syntax highlighting
• The Clarion community for feedback and testing

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Contributors ✨

Thanks to everyone who has helped improve the Clarion Language Extension through code, bug reports, testing, ideas, documentation and their knowledge of the Clarion language.

geircodes 💻 🐛 🤔	Edin Čahtarević 🐛 🤔 📓	ClarionLive 🐛 🤔 📓	Allen Zhu 💻	Brahn Partridge 💻	Mark Goldberg 🐛	Carlos Gutierrez 🐛
Dylan Vos 🐛	krosoftware 🐛	jslarveEC 🐛	Nardus 📖	Mike Hanson 🤔

This project follows the all-contributors specification. Contributions of any kind welcome!