Functional programs deal with structured data, are often nonrepetitive and nonrecursive, are hierarchically constructed, do not name their arguments, and do not require the complex machinery of procedure declarations to become generally applicable.Moreover, such programs are actually objects of an algebra whose composition laws are functional forms. Various properties on programs can thus be proved by use of college algebra.
A few more toplevel commands are available, these are:
form or function name Backus' syntax our syntax apply to all a @ division ÷ div or ÷ select nth n ns reverse select nr nr composition f ° g °...° h f o g o ... o h condition p ® f; g p -> f; g construction [f,g,...,h] [ f,g,...,h ] constant n
definition Def f º defs Def f = defs
Table 1: Syntax differences with original Backus description
#' and extend to the end of line.