VS Code custom editor for exploring GAMS .gdx files. It uses DuckDB-WASM + the duckdb_gdx extension to read symbols, preview data, run ad-hoc SQL, and export results.
Features
Open .gdx files in a custom editor with an interactive data grid.
Symbols tree: browse symbols, see dimensions and record counts.
One-click paging: quickly page through symbol data (LIMIT/OFFSET).
SQL panel: expand to run arbitrary queries against the currently opened GDX (uses read_gdx).
Display attributes: control numeric formatting (precision, format, squeeze defaults/zeros).
Export menu: export the current query result to CSV, Excel (xlsx), or Parquet via DuckDB COPY.
Automatic filter preloading is supported via background domain loading.
Requirements
VS Code 1.106.1 or newer.
Usage
Open a .gdx file in VS Code; the GDX Viewer custom editor will appear.
Select a symbol from the Symbols view; the first page (100 rows) is shown automatically.
Use paging controls in the grid to move through the data.
Open the SQL panel to run custom queries (Ctrl/Cmd+Enter to run). The placeholder __GDX_FILE__ is automatically replaced.
Use the Attributes button to adjust formatting.
Use Export → CSV/Excel/Parquet to write the current query to disk. The extension installs/loads DuckDB’s excel extension automatically for XLSX output.
Extension Settings
gdxViewer.autoLoadFilters (boolean, default: true) — Automatically load filter/domain values for the selected symbol in the background.
Development
Install dependencies: npm install
Build: npm run compile
Watch build: npm run watch
Run tests: npm test (compiles tests and launches VS Code test runner)
Known Issues
Large GDX files may still be slow to scan depending on environment; paging and filter loading run lazily to reduce perceived latency.
