Defining the label construct.

§1.

enum LABEL_IST

void Inter::Label::define?Usage of Inter::Label::define:
Definition - §3(void) {
    inter_construct *IC = Inter::Defn::create_construct(
        LABEL_IST,
        L"(.%i+)",
        I"label", I"labels");
    IC->min_level = 0;
    IC->max_level = 100000000;
    IC->usage_permissions = INSIDE_CODE_PACKAGE;
    METHOD_ADD(IC, CONSTRUCT_READ_MTID, Inter::Label::read);
    METHOD_ADD(IC, CONSTRUCT_VERIFY_MTID, Inter::Label::verify);
    METHOD_ADD(IC, CONSTRUCT_WRITE_MTID, Inter::Label::write);
}

§2.

define BLOCK_LABEL_IFLD 2
define DEFN_LABEL_IFLD 3
define EXTENT_LABEL_IFR 4

void Inter::Label::read?Usage of Inter::Label::read:
§1(inter_construct *IC, inter_bookmark *IBM, inter_line_parse *ilp, inter_error_location *eloc, inter_error_message **E) {
    if (Inter::Annotations::exist(&(ilp->set))) { *E = Inter::Errors::plain(I"__annotations are not allowed", eloc); return; }
    *E = Inter::Defn::vet_level(IBM, LABEL_IST, ilp->indent_level, eloc);
    if (*E) return;
    inter_package *routine = Inter::Defn::get_latest_block_package();
    if (routine == NULL) { *E = Inter::Errors::plain(I"'label' used outside function", eloc); return; }
    inter_symbols_table *locals = Inter::Packages::scope(routine);
    if (locals == NULL) { *E = Inter::Errors::plain(I"function has no symbols table", eloc); return; }

    inter_symbol *lab_name = InterSymbolsTables::symbol_from_name(locals, ilp->mr.exp[0]);
    if (Inter::Symbols::is_label(lab_name) == FALSE) { *E = Inter::Errors::plain(I"not a label", eloc); return; }

    *E = Inter::Label::new(IBM, lab_name, (inter_ti) ilp->indent_level, eloc);
}

inter_error_message *Inter::Label::new(inter_bookmark *IBM, inter_symbol *lab_name, inter_ti level, inter_error_location *eloc) {
    inter_tree_node *P = Inode::fill_2(IBM, LABEL_IST, 0, InterSymbolsTables::id_from_IRS_and_symbol(IBM, lab_name), eloc, level);
    inter_error_message *E = Inter::Defn::verify_construct(Inter::Bookmarks::package(IBM), P); if (E) return E;
    Inter::Bookmarks::insert(IBM, P);
    return NULL;
}

void Inter::Label::verify?Usage of Inter::Label::verify:
§1(inter_construct *IC, inter_tree_node *P, inter_package *owner, inter_error_message **E) {
    if (P->W.extent != EXTENT_LABEL_IFR) { *E = Inode::error(P, I"extent wrong", NULL); return; }
    inter_symbol *lab_name = InterSymbolsTables::local_symbol_from_id(owner, P->W.data[DEFN_LABEL_IFLD]);
    if (Inter::Symbols::is_label(lab_name) == FALSE) {
        *E = Inode::error(P, I"not a label", (lab_name)?(lab_name->symbol_name):NULL);
        return;
    }
    if (P->W.data[LEVEL_IFLD] < 1) { *E = Inode::error(P, I"label with bad level", NULL); return; }
    inter_symbols_table *locals = Inter::Packages::scope(owner);
    if (locals == NULL) { *E = Inode::error(P, I"no symbols table in function", NULL); return; }
    *E = Inter::Verify::local_defn(P, DEFN_LABEL_IFLD, locals);
}

void Inter::Label::write?Usage of Inter::Label::write:
§1(inter_construct *IC, OUTPUT_STREAM, inter_tree_node *P, inter_error_message **E) {
    inter_package *pack = Inter::Packages::container(P);
    inter_symbol *lab_name = InterSymbolsTables::local_symbol_from_id(pack, P->W.data[DEFN_LABEL_IFLD]);
    if (lab_name) {
        WRITE("%S", lab_name->symbol_name);
    } else { *E = Inode::error(P, I"cannot write label", NULL); return; }
}