flight

flight is a lightweight programming language.

summary

The source code of this program is for learning programming languages.
Also, it's not practical because arrays is not supported and only Japanese are supported.

---

how to use

The fastest way to call a scripting language from C++ is to see 'flight-test/flight-test.cpp' and 'flight/flight.h'.

#include "flight.h"

void main()
{
    flight f;

    do {
        // load script file
        if(!f.load_file("script.f")){ break; }
        if(!f.load_file("script2.f")){ break; }

        // call when all scripts are loaded
        if(!f.load_complete()){ break; }
        
        // script execution
        f.exec();
    } while(false);

    // Get the error
    if (f.get_last_error() != flight_errors::error_none)
    {
      printf("%s", f.get_last_error_string().c_str());
    }
}

---

script

See 'flight-test/script/test.f' for a sample script.
It can be written like C language.

The details are described below.

variable

var a;
var b = 10;
var c = a * b + 3;
var str = "string";
var str2 = str + "aaaa";
var ch = 'a';
var oct = 0123;
var hex = 0xff1;
var val1 = 10 , val2 = 20; // multiple declare

comment

// comment
/* comment */

if

var a = 10;
if( a == 10 ){ /* execute */ }
else if( a != 20 ) {}
else if( a > 10 ) {}
else {}

for

for( var i = 0 ; i < 10 ; i += 1 ) { /* execute */ }

while

var count = 0;
while( count < 5 ){ count += 1; }

function

func fuctorial( var value )
{
    if(value <= 1) { return 1; }
    return value * fuctorial( value - 1);
}

factorial(5);

print function (embedded)

print( 5 );
print( "abc" );
print( "value => " + 10 );

yield

yield returns processing to host.

yield;
yield 2; // Can be picked up by the host.

How to receive the yield value on the host side

flight_variable var;
f.get_exec_data(var);
printf("last data => %s\n", var.value.c_str());  // yield 2 is returned 2, yield is returned ""

function pointer

func mul( var a , var b ) { return a * b; }
var fp_prt = print;
var fp_mul = mul;

fp_prt( fp_mul( 2 , 3 ) );

---

Addition of embedded functions

cpp

Call regisiter_function method.

#include "flight.h"

void add(flight_variable& ret_var, const flight_variable& arg1, const flight_variable& arg2)
{
    ret_var.value = std::to_string(atoi(arg1.value.c_str()) + atoi(arg2.value.c_str()));
    ret_var.type = flight_data_type::FDT_VARNUMBER;
    return;
}

void main()
{
    flight f;

    do {
        // load script file
        if(!f.load_file("script.f")){ break; }
        if(!f.load_file("script2.f")){ break; }

        // call when all scripts are loaded
        if(!f.load_complete()){ break; }

        // !!! add embedded function
        if (!f.register_function("add", add)) { break; }

        // script execution
        f.exec();

script

// call host function
print( "value => " + add( 1 , 2 ) );

---

References

http://www.hpcs.cs.tsukuba.ac.jp/~msato/lecture-note/comp-lecture/note1.html

---

Explanation end