C.12 Appendix Summary

Haskell is a statically typed and type-safe programming language that primarily supports functional programming. Haskell uses homogeneous lists with list operators : (i.e., cons) and ++ (i.e., append). The language supports anonymous/λ functions (i.e., unnamed or literal functions). A key language concept in Haskell is that all functions have types. Another key language concept in Haskell is pattern-directed invocation—a pattern-action rule-oriented style of programming, involving pattern matching, for defining and invoking functions. This appendix provides an introduction to Haskell so that readers can explore type concepts of programming languages and lazy evaluation through Haskell in Chapters 7–9, and 12. Table 9.7 compares the main concepts in Standard ML and Haskell.