Lion Lang

A new programming language for kids, inspired by BASIC and Logo. Designed for simplicity, fun, and learning.

Language Specification

Goals

• Extremely simple syntax (one command per line)
• English-like keywords
• Immediate visual or text output
• Minimal setup, runs in a REPL or simple interpreter
• Safe: no complex types, no pointers, no advanced concepts

Types

• Integer: Whole numbers (e.g., 10, -5)
• Float: Decimal numbers (e.g., 3.14, -2.5)
• String: Text in double quotes (e.g., "hello")

Example Syntax

LET x = 10
LET y = 3.14
LET name = "Cub"
PRINT name
PRINT x + y

Functions

• Define with DEF and end with END
• Use RETURN to return a value

DEF SQUARE(n)
  RETURN n * n
END
PRINT SQUARE(5)

Built-in Functions

• PRINT(value): Output text or numbers to the console
• LEN(string): Returns the length of a string
• RANDOM(min, max): Returns a random integer between min and max
• TO_INT(value): Converts a value to integer
• TO_FLOAT(value): Converts a value to float
• TO_STRING(value): Converts a value to string
• SQRT(value): Returns the square root of a number
• ABS(value): Returns the absolute value
• ROUND(value): Rounds a float to the nearest integer

Example usage:

LET n = LEN("hello")
PRINT RANDOM(1, 10)
PRINT TO_STRING(123)
PRINT SQRT(16)

Core Features

1. Commands: PRINT, FORWARD, BACK, LEFT, RIGHT, CIRCLE, SET COLOR, REPEAT, END, LET, DEF, RETURN
2. Variables: Only integer, float, and string types
3. Functions: Simple function definition and call
4. Built-in functions: See above
5. REPEAT for loops, no conditionals at first
6. All numbers are integer or float
7. All strings in double quotes
8. Immediate drawing (turtle graphics) and text output

Example Program

LET side = 100
DEF draw_square(size)
  REPEAT 4
    FORWARD size
    RIGHT 90
  END
END
PRINT "Let's draw a square!"
draw_square(side)

Visual Feedback

• Turtle graphics window for drawing commands
• Console for PRINT output

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Want to help? Try writing a simple interpreter or suggest new commands!