C++ mode

C++ mode makes the Ravi shell act as a C++ interpreter. The interpreter reads a "command" which must be a single C/C++ instruction, executes it, and prints the result.

Let's look at a simple session of ravi in C++ mode: This example uses the modpoint module presented in module generation

 ravi -mod c++
 require( modpoint0);     // loading the module
:>help(Point);            // getting help about class
Point is C++class  
Module : modpoint0
parent class: #f
methods are:
     1 GetX
     2 GetY
     3 SetX
     4 SetY
     5 Set
     6 (c-operator -=)
     7 ObjectInfo
     8 constructor
:>help( 6);
Point::(c-operator -=) defined with 1 profile(s):
Point * operator-=(Point &);
:>p1=new Point(3,4);        // creating a point
<Point : (3 4)>
:>p1.GetX();                // calling a method
3
:>p2=new Point(p1);
<Point : (3 4)>
:>p2.SetX(12);              // calling another method
:>p2;
<Point : (12 4)>

Short notice

Usefull ways to activate C++ mode

ravi [-v] -mod c++ -scheme-trace [filename ...]

Switching between C++ mode and Lisp mode

The command scheme switches from C== to Lisp/Scheme. The function (c++-toplevel) switches from Scheme to C++.

Simplification of C++ syntax

In order to simplify interactive use, c++ mode accepts a modified C++ syntax.

• You may omit the semi-colon at the end of a command, it is added automatically. This implies your command is given on a single line. As with preprocessor commands, this line may be extended using the backslash character a the end.

• You may omit the parentheses for 1-argument functions.

This is very practical - the follwing 3 lines are strictly equivalent:

help(Point);
help(Point)
help Point

Scheme compatibility

Under C++ mode you have access to all parts of the Ravi environment, which includes (actually, it initially IS) a complete Scheme system. This has an annoying consequence: in Scheme, the hyphen (minus sign) is traditionnally used to separate the syllables of a symbol, rather than the underscore character used in C. This means Scheme identifiers are not legal identifiers in C. For this reason, the minus sign in C++ mode has the special property of being considered a letter if it follows a letter or digit. This can be annoying inside arithmetic expressions.

You can give the - sign its "pure C" syntax ...

Using Scheme functions in C++ mode

:>v=make-vector 10      
#(() () () () () () () () () ())
:>vector-length v
10
:>v[3]=19
19
:>v[3]*v[3]
361
:>string-length "imag"
4