Falcon (programming Language) - Paradigms - Functional

Functional

Falcon has an evaluation engine called Sigma-reductor, which allows programmers to write completely functional programs without the need to use any procedural construct, not differently from what is seen in Lisp. The intermixed programming style allows use of different paradigms (such as OOP or procedural approaches) in functional sequences, or to use functional evaluations during the course of otherwise procedural programs.

Functional sequences are represented by standard language arrays; this means that sequences can be created, inspected and changed dynamically by the program itself, either across different evaluations or during the course of a Sigma-reduction evaluation. The following example does that by changing a special variable reference, called late binding in a list loop.

seq = dolist( function(p); seq.value = p; eval(seq); end, )

Standard arrays can be called as functions if their first member is itself a callable item, as in the following example.

f = f( "Real data to print" )

One-level functional sequences (as in the above example) can be conceptually treated as cached calls, and once assigned to a variable, they are morphologically equivalent to a function symbol.

The functional paradigm includes an out-of-band item marker. Items can receive an oob flag marker which can be tested through language operators and functions and indicate a special meaning for values traveling in functional sequences. For example, many functional loops, as floop and times, can perform loop restarts or can be interrupted by returning either an out-of-band 1 or 0 from any of the involved functions. The map function, transforming all the values in an array through a mapping function, will ignore the returned value (discarding it) if it's an out-of-band nil; in this way, it is possible to perform map-and-filter operations in place.