Iain Duncan

A plea for help from the C external experts: I'm trying to implement functionality like tosymbol so that any message of atoms into s4m can be treated like a string to eval if it starts with '('. I've been trying this out with binbufs, and I can get the binbuf set with max atoms, and it has the right size, but I can't figure out how to safely get string content out of it that I can manipulate. If anyone has experience with these, help would be much appreciated. I put details and a code sample here:

https://github.com/iainctduncan/scheme-for-max/issues/101

code:
// IN PROGRESS
// I want this to take my array of atoms and return a string
// of them, just as tosymbol does
void s4m_tosymbol(t_s4m *x, t_symbol *s, int argc, t_atom *argv){
    post("s4m_tosymbol");
    //post(" - s: \"%s\" argc: %i", s->s_name, argc);
    char *token_1_str = s->s_name;
    
    void *binbuf = binbuf_new();
    binbuf_set(binbuf, NULL, argc, argv);

    char **buf_text = newhandle(0);
    t_ptr_size buf_size = 0; 
    int err = binbuf_totext(binbuf, buf_text, &buf_size);
    if(err){
      post("err in binbuf_totext");
    }
    post("binbuf filled, buf_size: %i", buf_size);

    // ?? how can I read text safely from buf_text and create
    // a new string that is ("%s %s", token_1_str, buf_text)??
    // the below sometimes prints the right thing, and other times has trailing garbage
    post("buf_text: %s", *buf_text);

    sysmem_freehandle(buf_text); 
    freeobject(binbuf);
    post("done");

}

A plea for help from the C external experts: I'm trying to implement functionality like tosymbol so that any message of atoms into s4m can be treated like a string to eval if it starts with '('. I've been trying this out with binbufs, and I can get the binbuf set with max atoms, and it has the right size, but I can't figure out how to safely get string content out of it that I can manipulate. If anyone has experience with these, help would be much appreciated. I put details and a code sample here:
https://github.com/iainctduncan/scheme-for-max/issues/101

A plea for help from the C external experts: I'm trying to implement functionality like tosymbol so that any message of atoms into s4m can b

need-help-replicating-tosymbol-functionality-stuck-on-binbuf-string-conversion

maybe I don't fully understand your issue, but if you want to convert atoms to a string of text I would do it like this:

void s4m_tosymbol(t_s4m *x, t_symbol *sym, long argc, t_atom *argv)

t_max_err err = atom_gettext(argc, argv, &size, &text, OBEX_UTIL_ATOM_GETTEXT_DEFAULT);

if (err == MAX_ERR_NONE && size && text) {

Be aware that if you convert the string to a symbol using gensym() you are gonna add to the Max symbol table.

void s4m_tosymbol(t_s4m *x, t_symbol *sym, long argc, t_atom *argv)
{
    long size = 0;
    char *text = NULL;
    t_max_err err = atom_gettext(argc, argv, &size, &text, OBEX_UTIL_ATOM_GETTEXT_DEFAULT);
    if (err == MAX_ERR_NONE && size && text) {
        // text contains your atom string
    }
    if (text) {
        sysmem_freeptr(text);
    }
}

Ah fantastic! I have to admit, I was dearly hoping you would see this Luigi. You got an acknowledgement in my paper at ICFP2021 btw. :-)

Ah fantastic! I have to admit, I was dearly hoping you would see this Luigi. You got an acknowledgement in my paper at ICFP2021 btw.  :-)


Ok I think this is as good as I get with C eh? It's working, though better coding pointers are always welcome and appreciated!

void s4m_eval_atoms_as_string(t_s4m *x, t_symbol *sym, long argc, t_atom *argv){
    post("s4m_eval_atoms_as_string");
    long size = 0;
    char *atoms_as_text = NULL;
    t_max_err err = atom_gettext(argc, argv, &size, &atoms_as_text, OBEX_UTIL_ATOM_GETTEXT_DEFAULT);
    if (err == MAX_ERR_NONE && size && atoms_as_text) {
        // atoms_as_text contains your atom string
        post("size: %i text: '%s'", size, atoms_as_text);
    }else{
      // TODO abort error here
    }
    char *token_1 = sym->s_name;
    int token_1_size = strlen(token_1);
    int code_str_size = token_1_size + size + 1;
    char *code_str = (char *)sysmem_newptr( sizeof( char ) * code_str_size);
    sprintf(code_str, "%s %s", token_1, atoms_as_text);
    post("code_str: %s", code_str);

   char *code_str_2 = (char *)sysmem_newptr( sizeof( char ) * code_str_size);
    for(int i=0, j=0; i < code_str_size; i++, j++){
        if(code_str[j] == '\\') code_str_2[i] = code_str[++j];
        else code_str_2[i] = code_str[j];
    }
    post("code_str cleaned: %s", code_str_2);
    // string will get returned and used like this:
    // s4m_s7_eval_c_string(x, code_str);

   if (atoms_as_text) {
        sysmem_freeptr(atoms_as_text);
    }
}


Fixed version in case you have additional (welcome) feedback. Thanks once again!

void s4m_eval_atoms_as_string(t_s4m *x, t_symbol *sym, long argc, t_atom *argv){
    post("s4m_eval_atoms_as_string");
    char *token_1 = sym->s_name;
    int token_1_size = strlen(token_1);
    long size = 0;
    char *atoms_as_text = NULL;

   t_max_err err = atom_gettext(argc, argv, &size, &atoms_as_text, OBEX_UTIL_ATOM_GETTEXT_DEFAULT);
    if (err == MAX_ERR_NONE && size && atoms_as_text) {
        int code_str_size = token_1_size + size + 1;
        char *code_str = (char *)sysmem_newptr( sizeof( char ) * code_str_size);
        sprintf(code_str, "%s %s", token_1, atoms_as_text);
        post("code_str: %s", code_str);
        // now we have code, but we need to clean up Max escape chars
        char *code_str_clean = (char *)sysmem_newptr( sizeof( char ) * code_str_size);
        for(int i=0, j=0; i < code_str_size; i++, j++){
            if(code_str[j] == '\\') code_str_clean[i] = code_str[++j];
            else code_str_clean[i] = code_str[j];
        }
        post("code_str cleaned: %s", code_str_clean);
        // call s4m
        s4m_s7_eval_c_string(x, code_str_clean);
    }else{
       // TODO abort error here
    }
    if (atoms_as_text) {
        sysmem_freeptr(atoms_as_text);
    }
}

Fixed version in case you have additional (welcome) feedback. Thanks once again! 

Screen Shot 2021-09-05 at 9.25.41 PM.png

First of all, thanks for the acknowledgement in your paper :)

Your code looks good and - above all - it does what it's supposed to.

First of all, thanks for the acknowledgement in your paper :)
Your code looks good and - above all - it does what it's supposed to.
Good job!

Need help replicating tosymbol functionality, stuck on binbuf string conversion.