Variables and Data Types in Scheme

July 8, 2024

In this post, we delve into variables and data types in Scheme. Learn how to declare variables, work with different data types like numbers, strings, and lists, and understand the concept of immutability in Scheme.

Variables in Scheme

In Scheme, variables are declared using the define keyword. For example:

(define x 10)
(define name "Alice")
(define my-list '(1 2 3 4))

Here, we have declared a variable x with the value 10, name as a string “Alice”, and my-list as a list containing numbers.

Data Types in Scheme

Scheme supports various data types including:

  • Numbers: Integers, decimals, fractions, etc.
  • Strings: Text enclosed in double quotes.
  • Lists: Collections of elements enclosed in parentheses.

For example:

(define num 42)
(define greeting "Hello, World!")
(define fruits '(apple banana cherry))

Immutability in Scheme

In Scheme, variables are immutable, meaning once a variable is bound to a value, it cannot be changed. If you need to update a value, you would create a new variable with the updated value.

Understanding variables and data types is fundamental in Scheme programming and forms the building blocks for writing efficient and concise code.