GUY

Graphing Utility for Your code

Visualize Python control flow directly inside Visual Studio Code.

GUY parses Python code, builds an interactive control-flow graph (CFG), and connects the graph back to your source code. Use it to understand branching logic, inspect complexity, and explore independent execution paths without leaving VS Code.

Features

• Generate a CFG from an entire Python file, a selected code range, or the function under the cursor.
• Explore the graph in an interactive preview with zoom, fit, center, and layout controls.
• Switch between simplified and detailed graph views.
• Navigate between graph nodes, edges, functions, independent paths, and source code.
• Inspect cyclomatic complexity, nodes, edges, decisions, and connected components.
• Highlight source code when selecting graph items.
• Get lightweight complexity suggestions and visual warnings for large graphs.
• Understand common Python constructs including if/elif/else, for, while, return, break, and continue.

Quick start

Run locally

Clone the repository, install dependencies, and open it in VS Code:

git clone https://github.com/gm64x/guy-vscode.git
cd guy-vscode
npm install
npm run compile

Press F5 in VS Code to launch an Extension Development Host with GUY enabled.

Generate your first graph

1. Open a Python file.
2. Open the Command Palette (Ctrl+Shift+P / Cmd+Shift+P).
3. Run GUY: Generate CFG from File.

For a focused view, select Python code and run GUY: Generate CFG from Selection, or place the cursor inside a function and run GUY: Generate CFG from Current Function.

Commands

Command	Description
GUY: Generate CFG from File	Builds a graph for the active Python file.
GUY: Generate CFG from Selection	Builds a graph for the selected Python code.
GUY: Generate CFG from Current Function	Builds a graph for the function containing the cursor.
GUY: Toggle Simplified/Detailed CFG View	Switches the current graph between simplified and detailed mode.

The file command is also available in the Python editor title bar. Selection and current-function commands are available in the Python editor context menu.

Working with the preview

The CFG preview provides:

• an interactive graph canvas with pan, zoom, fit, center, and reset controls;
• a sidebar for nodes, edges, functions, and independent paths;
• a metrics panel with the cyclomatic complexity formula;
• source navigation and highlighting from graph selections;
• a simplified/detailed view toggle.

Settings

Configure GUY through Settings or settings.json:

Setting	Default	Description
guy.autoOpenPreview	true	Open the CFG preview automatically after generation.
guy.graphLayout	top-bottom	Default graph direction: top-bottom or left-right.
guy.showMetricsPanel	true	Show the metrics panel in the preview.
guy.highlightCodeOnNodeClick	true	Highlight source code when nodes or edges are selected.
guy.maxNodesBeforeWarning	100	Warn when a graph exceeds this number of nodes.
guy.highComplexityThreshold	10	Complexity threshold for lightweight suggestions.

Requirements

• Visual Studio Code ^1.120.0.
• Python source files (.py or python language mode).

Development

npm install
npm run compile
npm test

Create a production bundle with:

npm run package

Example Python inputs are available in src/examples.

Limitations

• CFG generation currently supports Python only.
• Source with syntax errors may produce incomplete graphs because of parser recovery.
• Independent paths are hidden for very large graphs to keep the preview responsive.

Links

• Report an issue
• Source repository