OVERVIEW OF
                                   CLEO
                            Programming Language






Version:        1.00 (Dec 1992)
Author :        DIALLO Barrou


Introduction

    This work consists in a Pascal-like experimental programming language
including some 3d and 2d mathematical stuffes to generate 3D scenes for a
soon coming ray-tracer.
    This version includes loop-instructions, standard I/O controls,
expressions tests, floating point numbers, special 3d/2d types.

Package Contents:

    cleo:/
    Author              (Author's name & Adress , Copyright advertissement)
    makefile                       (Compiling rules to Amiga users)
    /bin
        cleo                        (Executable-code Encoder)
        inter                       (Interpreter program)
    /etc
       Cleo_exe_cfg                 (Interpreter Configuration file)
       Cleo_int_cfg                 (Encoder Configuration file)
    /cleobin                        (Cleo's executable-code files)
        cleo.out                    (Default Cleo's executable-code)
    /include                        (Encoder's include source files)
    /source                         (Encoder's code source files)
    /obj                            (Object.o files)
    /examples                       (Some demo samples)
    /inter
        makefile                        (Compiling rules to Amiga users)
        /include                        (Interpreter's include source files)
        /source                         (Interpreter's code source files)


How can I recompile the Encoder and the interpreter?


    On Amiga machines:  ( Release 1.3 , 2.0 or 3.0)

    1. Assign the cleo: directory
        Assign cleo: my_dir

    2. add a path to the interpreter and compiler:
        path cleo:bin add

    Ensure that you've got the Aztec C v5.01 compiler and the make command
    on your disk and type this.

    3. Edit these files : CLEO:makefile and CLEO:inter/makefile to change
        the path behind PROJET =

    4. Under your Shell type please:

        cd cleo:
        make
        cd inter
        make
        cd /
    And then if no errors occurs, you've got two executable files in the bin
    directory.


How can I compile and run a cleo program?

    The easiest way to show how cleo works, is to compile a sample in the
Examples directory:
    (type what's following)

    1>  cleo examples/hello.cl

    This will compile the hello.pas sample which stay the Examples
    directory. The default output file (etc/cleobis.out) is used to put
    the produced cleo-code.

    1> inter
                    (This will execute the default cleo-code)



Types:
        Types lenght depends to the machine on which Cleo was compiled.

        1. LONGREAL                     ( = double in C language)
        2. REAL                         ( = float in C language)
        3. LONGINT                      ( = long int in C language)
        4. INTEGER                      ( = int in C language)
        5. CHAR                         ( = char in C language)
        6. STRING
            ex:
                 str : STRING;
                 str2 : STRING;

                 str := 'Hello World!' ;

                 str2 : =str;
                 writeln(str2);

        7. BOOLEAN                      ( = 1 unsigned byte )
        8. POINT2D                      ( = 2 floats in C language)
            ex:
                pnt    :   POINT3D;

                pnt.x := 111;      pnt.y := 222;
                writeln( ' coords(x y) =' , pnt.x, '  ', pnt.y  );

        9. POINT3D                      ( = 3 floats in C language)
            ex:

                pnt1, pnt2 : POINT3D;

                pnt1.x := 111;      pnt1.y := 222;      pnt1.z := 333;
                pnt2 := pnt1;
                writeln(' y= ', pnt2.y);

        10. RGB                      ( = 3 unsigned char in C language)
            ex:
                col :  RGB;

                col.r := 111;      col.g := 222;      col.b := 333;
                writeln(' red = ', col.r);

        11. ARRAY  ...   OF CHAR, OF INTEGER, OF REAL, OF BOOLEAN,
                        OF POINT3D, OF POINT2D, OF RGB.

Mathematical operators:

    +, -, /, * .
    % , mod : modulo

Logical operators:

    And, Or, Xor.


Operators priority:

    (High priority)
    * / AND MOD DIV
    + - OR
    < <= => > <>

Mathematical functions:

   abs , atan, acos, asin, cosh, sinh,
   cos, sin, exp, ln, sqr,
   sqrt, inv, rnd, tan, tanh,

Extra functions:

    odd(x)      :   return 1 if x is an odd value
                        else return 0
    even(x)     :   return 1 if x is an even value
                        else return 0
    pred(x)     :   return the predececor of x
    succ(x)     :   return the successor of x
    int(x)      :   return the integer part of x
    frac(x)     :   return the floating part of x

Break Instructions:

    1. WHILE expression DO instruction;
    2. REPEAT instruction UNTIL expression;


Tests Instructions:

    1. IF expression THEN instruction; <ELSE instruction;>


I/O Functions:

    1. Output functions:

    1.1. WRITE ( EXPRESSION | CONSTANTS ...);
    1.2. WRITELN < (EXPRESSION | CONSTANTS) ...> | <;>

    Write and Writeln are the same functions. Writeln just prints out a
    carriage return at the end of line.
    A Writeln function alone (without arguments) stands for a carriage
    return.

    2. Input functions:

    2.1. READ ( variable, variable, ...);
    2.2. READLN ( variable, variable, ...);



Porting Conventions:

    This language was developped with Aztec C 5.01 on Commodore Amiga and
entirely written in C language. It can be compiled on UNIX* Workstations or
on IBM PC/XT/AT by #defining during compilation 'unix' or 'msdos'.


Known bugs:

    1. Types conversions are not yet implemented, no errors or warning will
occurs when you attempt to assign a real to an integer variable!
    2. Array under-overflow aren't ckecked.
    3. Arrays fisrt index must be 1.

Author:

Please help me to improve new versions of Cleo,
    send please bug reports, or suggestions to :

    DIALLO Barrou
    23, rue des enfants de choeur
    51210 MONTMIRAIL
    FRANCE

*UNIX is a trademark of AT&T Bell Laboratories.