# Vienna Definition Language

> programming language

**Wikidata**: [Q21467844](https://www.wikidata.org/wiki/Q21467844)  
**Source**: https://4ort.xyz/entity/vienna-definition-language

## Summary
The Vienna Definition Language (VDL) is a programming language designed for expressing operational semantics. It is commonly referenced by the short name "VDL" and was developed by IBM.

## Key Facts
- Vienna Definition Language (VDL) is a programming language.  
- VDL is used for operational semantics (a category of formal programming language semantics).  
- The commonly used alias for Vienna Definition Language is "VDL".  
- VDL was developed by IBM.  
- VDL has a FOLDOC identifier: "Vienna+Definition+Language".  
- VDL has Wikipedia pages in German (de) and Spanish (es).  
- VDL’s Wikidata description is "programming language".  
- VDL’s Google Knowledge Graph identifier is /g/1234nbx6.  
- VDL has 2 sitelinks recorded on its structured entry.

## FAQs
### Q: What is the Vienna Definition Language?
A: The Vienna Definition Language (VDL) is a programming language intended for specifying operational semantics. It is often referred to by the abbreviation "VDL".

### Q: Who developed VDL?
A: VDL was developed by IBM.

### Q: What is VDL used for?
A: VDL is used to express operational semantics, which is a formal approach for defining the behavior of programming languages.

### Q: Where can I find more information about VDL?
A: Structured identifiers for VDL include a FOLDOC entry ("Vienna+Definition+Language"), Wikipedia pages in German and Spanish, and a Google Knowledge Graph ID (/g/1234nbx6).

## Why It Matters
Vienna Definition Language matters because it provides a formal, machine-oriented way to describe the operational semantics of programming languages. Operational semantics is a key category of formal programming language semantics used to define how program statements change system state step by step. By being explicitly tied to operational semantics, VDL serves as a tool for language designers, semantics researchers, and engineers who need precise, executable or checkable descriptions of language behavior. The fact that VDL was developed by IBM associates it with an industrial-origin effort to formalize language definitions. Presence in reference resources (FOLDOC) and multilingual Wikipedia coverage indicate that VDL has a recognized place in documentation and historical records about programming-language semantics.

## Notable For
- Being a programming language specifically used to express operational semantics.  
- Having been developed by IBM.  
- Having a FOLDOC entry under the identifier "Vienna+Definition+Language".  
- Having Wikipedia coverage in at least two languages (German and Spanish).  
- Appearing in structured knowledge resources (Wikidata description and Google Knowledge Graph ID).

## Body

### Overview
- Name: Vienna Definition Language.  
- Alias: VDL.  
- Classification: Instance of "programming language".  
- Primary use: Operational semantics.

### Use and classification
- VDL is associated with operational semantics, a category of formal programming language semantics.  
- Operational semantics is described as a category of formal programming language semantics; VDL is used within that category.

### Development and provenance
- Developer: IBM.  
- IBM (developer) appears in the structured record for VDL.  
- (Developer context) IBM’s inception is recorded as 1911-06-16 in the related developer metadata.

### Identifiers and links
- FOLDOC identifier: "Vienna+Definition+Language".  
- Google Knowledge Graph ID: /g/1234nbx6.  
- Wikidata description: "programming language".  
- Sitelink count on the structured entry: 2.  
- Wikipedia language pages recorded: German (de) and Spanish (es).

### Related concepts
- Programming language (class): general category for languages that communicate instructions to a machine.  
- Operational semantics (class): a category of formal programming language semantics to which VDL is applied.