Karlal

Karlal (also sometimes spelled Karlal in derivative texts) is a constructed programming language designed by Dr. Richard E. Pattis and originally intended as a simplified introduction to fundamental programming concepts for novice learners, particularly focusing on structured programming. It is characterized by its extreme simplicity, operating within a grid world where a robot, named "Karel," follows instructions to navigate the grid, pick up objects (usually "beepers"), and place them in specific locations.

The language focuses on a very limited instruction set. The core commands usually include movement (e.g., move), turning (e.g., turnLeft), picking up objects (e.g., pickBeeper), and putting down objects (e.g., putBeeper). Conditional statements based on Karel's environment (e.g., "if there is a beeper present") and iteration constructs (e.g., "while there is a wall in front") allow for more complex algorithms to be implemented.

Karlal’s primary purpose is pedagogical. Its limited scope allows learners to grasp the fundamental concepts of sequential execution, conditional branching, iteration, and decomposition into smaller, reusable procedures (functions). The visual representation of Karel's actions in the grid world provides immediate feedback, facilitating understanding and debugging.

The name "Karel" is reportedly derived from the play R.U.R. (Rossum's Universal Robots) by Karel Čapek, which introduced the word "robot" to the English language.

Due to its simplicity, Karlal is not intended for practical, real-world software development. It serves as a stepping stone towards learning more complex programming languages. Numerous variations and implementations of Karlal exist, often tailored to specific educational environments or integrated into interactive learning platforms. These implementations frequently add features or modify syntax to enhance the learning experience.