distance.c

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/*****************************************************************************
 * ugBASIC - an isomorphic BASIC language compiler for retrocomputers        *
 *****************************************************************************
 * Copyright 2021-2026 Marco Spedaletti (asimov@mclink.it)
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 * Licensed under the Apache License, Version 2.0 (the "License");
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/****************************************************************************
 * INCLUDE SECTION 
 ****************************************************************************/
 
#include "../../ugbc.h"
 
/****************************************************************************
 * CODE SECTION 
 ****************************************************************************/
 
extern char DATATYPE_AS_STRING[][16];

/* <usermanual>
@keyword DISTANCE
 
@english
 
The ''DISTANCE'' function calculates the geometric distance between two points. 
The distance is calculated with the application of the Pythagorean theorem, 
the result of which is however returned with the nnly integer part. If any 
component is omitted, the last screen position is used, instead.
 
@italian
La funzione ''DISTANCE'' calcola la distanza geometrica tra due punti. 
La distanza viene calcolata con l'applicazione del teorema di Pitagora, il cui 
risultato viene comunque restituito con la sola parte intera. Se viene omessa
una qualsiasi delle componenti, viene usata quella corrispondente all'ultima
position dello schermo.
 
@syntax = DISTANCE( [x1], [y1] TO [x2], [y2] )
 
@example result = DISTANCE( x1, y1 TO x2, y2 )
 
@usedInExample maths_distance_01.bas
</usermanual> */
Variable * distance( Environment * _environment, char * _x1, char * _y1, char * _x2, char * _y2 ) {
 
    Variable * x1 = variable_retrieve_or_define( _environment, _x1, VT_POSITION, 0 );
    Variable * y1 = variable_retrieve_or_define( _environment, _y1, VT_POSITION, 0 );
    Variable * x2 = variable_retrieve_or_define( _environment, _x2, VT_POSITION, 0 );
    Variable * y2 = variable_retrieve_or_define( _environment, _y2, VT_POSITION, 0 );
    Variable * two = variable_resident( _environment, VT_POSITION, "(two)");
    
    variable_store( _environment, two->name, 2 );
 
    Variable * sum = variable_add( 
                    _environment,
                    powering( _environment, 
                        variable_sub( _environment,
                            x1->name,
                            x2->name
                        )->name, 
                        two->name 
                    )->name,
                    powering( _environment, 
                        variable_sub( _environment,
                            y1->name,
                            y2->name
                        )->name, 
                        two->name
                    )->name
                );
 
    Variable * result = variable_cast( _environment, sum->name, VT_POSITION );
 
    MAKE_LABEL
 
    variable_move(
            _environment,
            sqroot(
                _environment,
                result->name                 
            )->name,
            result->name
    );
 
    return result;
}