Clarion language support for Visual Studio Code: navigation, hover, IntelliSense, diagnostics, refactoring and builds, backed by a language server that understands whole solutions. Built and measured against real generated applications, 40 projects and 3,000 source files at a time, so the things a Clarion IDE user expects to work on a generated app, ABC or Legacy templates alike, work here too.
- Quick start — five minutes to your first solution
- Common tasks — how do I…
- Changelog — what changed in each release
- Issues — bugs and requests
Works in the current file with no solution open; opens out across files when a solution is loaded.
- F12, Ctrl+F12 and Shift+F12 for definition, implementation and references, aware of scope, overloads, routines,
PRE:FieldandStructure.Fieldaccess, and the procedure names an EXE shares with its DLLs. - Hover cards that say what a thing is: a FILE with its driver, prefix and keys; a MAP prototype labelled Global, Module or Private; a structure field the same from its declaration or any qualified use.
- Reference counts above every procedure, method, class and routine, exact once the index is warm.
- Rename across the workspace, document highlight, workspace symbol search, and chained access such as
SELF.Order.RangeList.Initresolved through CLASS, QUEUE and GROUP types. - Call hierarchy (Shift+Alt+H) for procedures, methods and routines, in both directions.
- Hover on a keyword that only makes sense in context: an
ENDor a period says which structure it closes and links back to it;ELSE,ELSIF,OFandOROFsay which IF or CASE they belong to. - In a solution with several projects, a name is resolved through the redirection of the project that compiles the file you are in.
- Navigation in detail
- Member completion after
SELF.,PARENT.,MyVar.orClassName., walking inheritance and honouring PRIVATE and PROTECTED. - Parameter hints for 272 built-in functions and for class methods, with the overload narrowed by the argument types as you type.
- Documented completions and hover for
PROP:,PROPPRINT:andEVENT:equates, and for?field equates scoped to the current window. - Signature help in detail
Reported as you type, following the compiler's rules; where the rule was unclear it was settled by compiling a fixture.
- Unterminated structures, missing RETURN, FILE validation, VIEW field references checked against the owning file.
- Missing INCLUDE and missing project DefineConstants, each with a quick fix that adds the line.
- Discarded return values, a literal passed by reference, a call to a PRIVATE procedure from another module, undeclared variables, missing implementations and indistinguishable overloads.
- Character-set validation that respects every Windows ANSI code page and the Clarion 12
!UTF8directive. - Every check has its own setting and its own severity, with one switch for all of them; changes take effect as you make them.
- Opt-in: a call to a procedure that no MAP, MODULE, include or indexed file declares.
- Diagnostics in detail
On Ctrl+.: Surround With, Negate Condition, Flip IF/ELSE, Introduce EQUATE, and Create routine from an unresolved DO. Code editing in detail
- Open a folder; the extension finds the
.sln, reads the projects, and follows Clarion's redirection files exactly as the IDE does, including per-configuration sections. - Installed Clarion versions are discovered from the IDE's settings; a
ClarionProperties.xmlkept anywhere else can be chosen, and the build follows it. - Build from the Solution View with live output, projects ordered by dependency, and each build states what it is building, in which configuration, and the MSBuild command line. A solution that loads in a degraded state says so instead of silently returning nothing.
- The Clarion version is remembered per solution and can be changed while it is loaded: the editor and the build follow the new install at once, without a reload. A version the properties file no longer registers is reported rather than used.
- Settings are read and written in one place, so a pick sticks in a multi-root workspace; settings an earlier version wrote into a folder, which override the
.code-workspacefile, are reported with an offer to remove them. - Project Properties and Solution Properties show a project's and a solution's options as the Clarion IDE's pages do; New Solution builds projects from the programs already in a folder.
- Solution management in detail
Syntax highlighting for Clarion and the template language, including the Clarion 12 Unicode preview; folding; 99 snippets; Paste as Clarion String; Add Method Implementation; a New Class wizard; a document formatter. Template files get highlighting only. Snippet reference
Indexes persist across sessions and background work is time-sliced, so a 40-project solution is ready in about two seconds and interactive in about five, and typing, hover and navigation are never blocked. Reading a source file is about three times faster than in 1.0.3, and background checking stops as soon as you type rather than finishing work your edit has already replaced. Opt-in tracing (clarion.log.performance.enabled) produces a full timeline for support, and clarion.log.level captures a diagnostic log for a bug report.
- Windows. The extension drives Clarion's own toolchain and does not run on macOS or Linux.
- Visual Studio Code 1.97 or later.
- Clarion 10, 11 or the 12 beta, for solution features and builds; editing and single-file navigation work without one.
Install from the Marketplace: open Extensions (Ctrl+Shift+X), search for Clarion Extensions, and install. Detailed installation instructions.
Projects and solutions managed in VS Code as in the Clarion IDE, and code read the way the compiler reads it.
- Project Properties and Solution Properties show a project's and a solution's options as the Clarion IDE's pages do; projects can be added, sources, references and pragmas edited, and the Solution View shows each project's IDE folders.
- New Solution asks everything on one page and builds a project for each program already in a folder, with its references and export files, following a legacy .prj where one compiles the program.
- An INCLUDE inside a COMPILE or OMIT block that does not compile is no longer followed, decided from the equates before it and the project's defines.
- Prototypes and headers continued with
|, LIKE declarations and the attributes of CLASS, QUEUE and variable lines read correctly in hover, the Outline, Find All References and the diagnostics; BREAK and CYCLE show the loop they act on, and EXPORT has a card. - TXA files are highlighted.
Earlier: 1.0.9 (2026-10-24) added hover cards that list and edit a declaration's attributes and resolved solutions with custom-named versions and redirection layouts; 1.0.8 (2026-10-04) made diagnostics after an edit about three times quicker on large modules and let hover, completion and Go to Definition run ahead of the background check. Full changelog.
- Guides: Quick start, Common tasks, Installation
- Features: Navigation, Signature help, Solution management, Diagnostics, Code editing
- Reference: Commands, Settings, Snippets, Clarion language reference (wiki)
- GitHub Issues for bugs and requests
- Discussions for questions and tips
- fushnisoft for the original Clarion syntax highlighting
- The Clarion community for feedback and testing
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 🤔 |
 William Atchison 🐛 🤔 |
This project follows the all-contributors specification. Contributions of any kind welcome!