It is a search through a symbol table, a query of function's environment. The paper argues that all the variety of OO species has sprung from different structures of underlying databases-environments, which hold the data and their labels. Conversely, a way queries to these databases are formulated and executed has everything to do with how powerful and expressive the corresponding OO system is. Furthermore, reading of input and character-dispatch can also be considered term evaluation. The difference between the two types of evaluators is especially noticeable when they face a term with a bottom subterm.
Normal evaluators can sometimes escape the bottom 's grasp.
This article exposes bottom terms for all four evaluators and shows how some of them are able to cope with insane input. The laziness of the lexer however can be its saving grace. Fibonacci sequence re-written from a previously published Haskell code, which was beautiful indeed. The current version is 1.1, Dec 23, 1998. The summary ends with a fascinating discussion about general rules of programming lazy computations in a strict language.