• Summary
• Acknowledgments
• Getting Started


• Overview of Scheme
• Lexical conventions
• Basic concepts
• Expressions
• Program structure
• Standard procedures


• Haskell Interface


• Standard Libraries
• Husk Libraries
• Standard Feature Identifiers
• Index

The REPL

Husk provides an interactive session called a REPL (Read-Eval-Print Loop), where import declarations, expressions and definitions can be entered and evaluated one at a time. For convenience and ease of use, the global Scheme environment in a REPL must not be empty, but must start out with at least the bindings provided by the base library. This library includes the core syntax of Scheme and generally useful procedures that manipulate data. For example, the variable abs is bound to a procedure of one argument that computes the absolute value of a number, and the variable + is bound to a procedure that computes sums. The full list of (scheme base) bindings can be found in Appendix A.

An implementation may provide a mode of operation in which the REPL reads its input from a file. Such a file is not, in general, the same as a program, because it can contain import declarations in places other than the beginning.

The Husk REPL can be started by running the huski program.