Re: [Vala] Starting with Vala, problems with strings

[Diego Jacobi <jacobidiego gmail com>]

Hi again.
I am still having troubles with things that i should easily do in C.
Maybe because i have never programmed in C#, or mono or anything like
it.

In my test code i want to split a math sentence in terms, like the
next string example:
"(2+a)*d+(a*b-3)-4-q/2"

My function split_in_terms, is a very bad implementation (i know) that
should split the string into 4 terms, and if not possible, return
NULL.
For that i have tryed with a List, but when using nth_data it prints
this string: "g_list_nth_data", only once. So i think that Lists are
not yet fully implemented so i switched to Array.
Where now i cant compile it.
ERROR:arraylist.c:322:gee_array_list_real_get: assertion failed: (_tmp0)

And i dont have any clue where the problem is.

Also i dont know when should i use pointers in Vala.
I know from C that every object must be defined as a pointer, but the
Vala bindings, doesnt defines them as pointer, so, why should i add an
*
If i dont add it, i cant change the value of the parameter.
supouse a function like next:
private static void split_in_terms(string strmath, string* term_left,
string* term_right)
This also gives a lot of warnings  for term_left and right.

Please note too the casting in:  new Array<string>(false, true,
(uint)sizeof(string));
Seems like the new array requires an ulong instead of uint which is
returned by sizeof. I dont know if this is the correct behavior or
not, but it seems strange.



    private static Array<string>* split_in_terms(string strmath)
    {
    int x = 0;
    int parentesis=0;
    Array<string> list = new Array<string>(false, true, (uint)sizeof(string));
    string str = strmath;
    StringBuilder term = new StringBuilder("");
        int p = 0;

    stdout.printf("str = %s\n", str);

        for(weak string s = str; s.get_char()!=0 ; s = s.next_char())
                {
                unichar c = s.get_char();
            if ( c == '(')
                {
            parentesis++;
                term.append_unichar(c);
                }
            else if ( c == ')')
                {
            parentesis--;
                term.append_unichar(c);
                }
            else if ( c == '+')
                {
            if ( parentesis == 0)
                {
                list.append_val( term.str );

                print("%s\n",term.str);
                term = new StringBuilder("");
                p = x+1;
                if ( str.len() >= p )
                        list.append_val( "+" );
                }
                }
            else
                {
                term.append_unichar(c);
                }
                x++;
                }
        list.append_val( term.str );

    if (parentesis != 0)
        {
        stdout.printf("SintaxERROR: Los parentesis no cierran
adecuadamente: %s\n", str);
        return null;
        }
    return &list;
    }

    public void calculate ()
    {
            double mean, max, min;
            string str = "holaaa+world";

            print ("1");
            Array<string>* list = split_in_terms( str );

        print ("2");
            for (int i = 0; i < list->length; i++)
                        stdout.printf ("term%d = %s\n", i, list->index(i));
/*            for (int i = 0; i < list->length(); i++)
                        stdout.printf ("term%d = %s\n", i, list->nth_data (i)*/);*/
                print ("3");
.....




Cheers.
Diego