What is MIME type "text/x-coq"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

The MIME type text/x-coq is designed for files that contain Coq proof scripts. These files hold formal logic statements and commands that help build and verify mathematical proofs.

They are used as part of an interactive environment where the Coq proof assistant checks each step of a proof. The scripts allow users to define concepts, state theorems, and develop proofs over time.

Core purpose: Marks files with Coq commands for formal verification.
Functionality: Contains instructions that are parsed and processed by Coq.
Use cases: Used in theorem proving, academic research, and software verification.

The associated file format uses the file extension V.

For more details on Coq, see the Coq Project.

Associated file extensions

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: text/x-coq

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="text/x-coq">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');    
    
    http.createServer((req, res) => {    
      res.setHeader('Content-Type', 'text/x-coq');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

FAQs

How do I configure Apache or Nginx to serve Coq files?

To ensure .v files are served with the correct MIME type, you must update your server configuration. For Apache, add AddType text/x-coq .v to your configuration or .htaccess file. For Nginx, add text/x-coq v; inside the types block in nginx.conf.

Why is the .v extension also associated with Verilog?

The .v extension is ambiguous and used by both Coq (text/x-coq) and Verilog (hardware description language). Automated systems often struggle to distinguish them based on the extension alone. You may need to inspect the file header or content to determine if it contains Coq proofs or Verilog circuit designs.

Can web browsers display text/x-coq files natively?

Browsers do not have built-in support for rendering or syntax highlighting Coq scripts. If a server sends the text/x-coq header, most browsers (like Chrome or Firefox) will default to downloading the file. To view it in-browser, the server usually needs to send it as text/plain.

What software is required to open files with this MIME type?

Files identified as text/x-coq are intended for the Coq Proof Assistant. The most common tools for editing these files are CoqIDE, Proof General (for Emacs), and VsCoq (for VS Code). However, since they are plain text, any basic text editor can open them.

Is text/x-coq a standard IANA MIME type?

No, the x- prefix indicates that text/x-coq is a non-standard or experimental subtype. While it is not officially registered with IANA, it is the widely accepted convention used by the Coq community and Linux distributions to identify Coq source files.

Are there security risks involved with opening Coq scripts?

Generally, text/x-coq files are harmless plain text. However, compiling or stepping through a malicious script in a Coq environment could theoretically cause resource exhaustion (infinite loops) or utilize unsafe plugin features. Always verify the source of a script before running it in an interactive prover.

General FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.