Expressions

A Scheme expression is a construct that returns a value, such as a variable reference, literal, procedure call, or conditional.

Expression types are categorized as primitive or derived. Primitive expression types include variables and procedure calls. Derived expression types are not semantically primitive, but can instead be explained in terms of the primitive constructs as in section . They are redundant in the strict sense of the word, but they capture common patterns of usage, and are therefore provided as convenient abbreviations.

• Primitive expression types
  • Variable references
  • Literal expressions
  • Procedure calls
  • s
  • Conditionals
  • Assignments
  
  
• Derived expression types
  • Conditionals
  • Binding constructs
  • Sequencing
  • Iteration
  • Delayed evaluation
  • Quasiquotation