# Portable Standard Lisp

> tail-recursive dynamically bound dialect of Lisp

**Wikidata**: [Q7231352](https://www.wikidata.org/wiki/Q7231352)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Portable_Standard_Lisp)  
**Source**: https://4ort.xyz/entity/portable-standard-lisp

## Summary
Portable Standard Lisp (PSL) is a dialect of the Lisp programming language designed to be tail-recursive and dynamically bound. It is classified as a programming language used for communicating instructions to a machine. The implementation follows a discipline of dynamic typing.

## Key Facts
- **Classification:** Portable Standard Lisp is a dialect of Lisp and an instance of a programming language.
- **Acronym:** It is commonly abbreviated as **PSL**.
- **Typing Discipline:** The language utilizes **dynamic typing**.
- **Binding:** It features **dynamic binding** for variables and functions.
- **Execution:** The dialect is defined as **tail-recursive**, optimizing recursive function calls.
- **Wikipedia Presence:** It has a designated Wikipedia title and presence in the English language.
- **Identifier:** The entity holds the Freebase ID `/m/0brz3l`.

## FAQs
### Q: What type of programming language is Portable Standard Lisp?
A: Portable Standard Lisp is a dialect of the Lisp programming language. It is characterized as a language for communicating instructions to a machine.

### Q: What are the key technical characteristics of PSL?
A: PSL is defined by three main technical characteristics: it is tail-recursive, dynamically bound, and dynamically typed.

### Q: Is Portable Standard Lisp statically or dynamically typed?
A: Portable Standard Lisp is dynamically typed. This means type checking is performed at runtime rather than compile time.

## Why It Matters
Portable Standard Lisp (PSL) serves as a specific implementation within the broader Lisp family, distinguished by its adherence to tail-recursion and dynamic binding. As a programming language, it functions as a tool for instructing machines, fitting within the historical ecosystem of Lisp dialects that prioritized flexible data manipulation and symbolic computation. Its "Portable" designation implies a design focus on implementation across different hardware architectures, though its core definition rests on its specific handling of recursion and variable scope. By employing dynamic typing and dynamic binding, PSL allows for greater flexibility during runtime, a hallmark of the Lisp programming paradigm. This combination of features defines its utility and specific niche in the landscape of computer science languages.

## Notable For
- **Tail-Recursion:** Unlike some earlier Lisp dialects, PSL is explicitly defined as tail-recursive, allowing for efficient iterative processes via recursion.
- **Dynamic Binding:** It employs dynamic binding, a scope strategy where variable bindings are determined at runtime.
- **Dynamic Typing:** The language operates under a dynamic typing discipline, distinct from statically typed languages.
- **Lisp Dialect:** It represents a specific variation of the Lisp language family, tailored for specific computational needs.

## Body
### Overview
Portable Standard Lisp (PSL) is identified as a **programming language** and a **dialect of Lisp**. It serves the fundamental purpose of communicating instructions to a machine.

### Technical Specifications
The architecture of Portable Standard Lisp is built upon specific computational concepts derived from its source description:

- **Recursion:** The language is designed to be **tail-recursive**. This property allows functions that call themselves as their final action to be executed without adding new stack frames, converting recursion into iteration internally.
- **Variable Binding:** PSL uses **dynamic binding** (also known as shallow binding in some contexts). This means that during the execution of a function, free variables refer to the bindings established by the most recent function call in the call stack.
- **Typing:** The typing discipline is explicitly listed as **dynamic typing**. Variables are not bound to specific types at compile time; rather, values have types, and variables can hold values of any type.

### Identifiers and Metadata
Portable Standard Lisp is cataloged under the alias **PSL**. Within knowledge graphs, it is associated with the Freebase identifier `/m/0brz3l`. It maintains a presence on Wikipedia with one sitelink in the English language.