Proteus

Introduction

Proteus was initially created as a system utility for MS-DOS, Windows, and Unix to manipulate text and binary files and create CGI scripts. The language was later focused on Windowswith hundreds of specialized functions for: network and serial communication, database interrogation, system service creation, console applications, keyboard emulation, and ISAPI scripting (for IIS). Most of these additional functions are only available in the Windows flavour of the interpreter, even though a Linux version is still available.

Proteus was designed to be practical (easy to use, efficient, complete), readable and consistent.

Its strongest points are:

powerful string manipulation

comprehensibility of Proteus scripts

availability of advanced data structures: arrays, queues (single or double), stacks, bit maps, sets, AVL trees.

The language can be extended by adding user functions written in Proteus or DLLs created in C/C++.

Language features

At first sight, Proteus may appear similar to Basic because of its straight syntax, but similarities are limited to the surface:

Proteus has a fully functional, procedural approach;

variables are untyped, do not need to be declared, can be local or public and can be passed by value or by reference;

all the typical control structures are available (if-then-else; for-next; while-loop; repeat-until; switch-case);

new functions can be defined and used as native functions.

Data types supported by Proteus are only three: integer numbers, floating point numbers and strings. Access to advanced data structures (files, arrays, queues, stacks, AVL trees, sets and so on) takes place by using handles, i.e. integer numbers returned by item creation functions.

Type declaration is unnecessary: variable type is determined by the function applied – Proteus converts on the fly every variable when needed and holds previous data renderings, to avoid performance degradation caused by repeated conversions.

There is no need to add parenthesis in expressions to determine the evaluation order, because the language is fully functional (there are no operators).

Proteus includes hundreds of functions for:

accessing file system;

sorting data;

manipulating dates and strings;

interacting with the user (console functions)

Synopsis and licensing

The main features of this language are:

fully functional, procedural language;

no data types: all variables can be used as integer numbers, floating point numbers or strings; variables are interpreted according to the functions being applied – Proteus keeps different representations of their values between calls, to decrease execution time in case of frequent conversions between one type and the other;

no pre-allocated structures: all data used by Proteus are dynamically allocated at execution time; there are no limits on: recursion, maximum data size, number of variables, etc.;

no operators: As a completely functional language, there are no operators; thus, there is no ambiguity when evaluating expressions and parenthesis are not needed;

large library of predefined functions: Proteus is not a toy-language, it comes with hundreds of library functions ready to be used for working on strings, dates, numbers, for sorting, searching and so on;

advanced data access (DAO), pipes, Windows sockets, serial ports: in the Windows version, Proteus includes hundreds of system calls which are operating system-specific;

clear and comprehensible syntax: the names of the library functions resemble those of corresponding functions in C, Clipper/Flagship and Assembly; by using medium-length keywords, Proteus programs are very easy to understand;

native support for high-level data structures: arrays, queues (single or double), stacks, bit maps, sets, AVL trees are already available in Proteus and do not require additional code or libraries to be used;

ISAPI DLL and Windows Service versions: Proteus is available as a Windows service or as an ISAPI DLL (for using together with Microsoft Internet Information Server);

Example programs

Hello World

The following example prints out "Hello world!".

CONSOLELN "Hello World!"

Extract two fields

The following example reads the standard input (CSV format, separator ";") and prints out the first two fields separated by "|":

CONSOLELN TOKEN(L, 1, ";") "|" TOKEN(L, 2, ";")

Proteus scripts by default work on an input file and write to an output file; the predefined identifier L gets the value of every line in input. The function TOKEN returns the requested item of the string; the third parameter represents the delimiter. String concatenation is implicit.

The same program can be written in this way:

H = TOKNEW(L, ";")CONSOLELN TOKGET(H, 1) "|" TOKGET(H, 2)TOKFREE(H)

In this case, we used another function (TOKGET), which builds the list of the tokens in the line; this is more efficient if we need to access several items in the string.