Trees

Create rows and release iterators

tree creates a file-style tree with labels, paths and directory state. tree_append returns an allocated iterator. Freeing the iterator releases its wrapper, not the row in the model.

import gui
let add_root = fn (tree:u8*) -> i64 {
    let row = Gui:tree_append(tree, cast(u8*, 0), "Sources", "src", 1)
    if !row { return 0 }
    defer Gui:tree_iter_free(row)
    Gui:tree_mark_loaded(tree, row)
    return 1
}
let print_selected_path = fn (tree:u8*) -> i64 {
    var directory:i32 = 0
    let path = Gui:tree_selected_path(tree, &directory)
    if !path { return 0 }
    defer Gui:text_free(path)
    printf("selected: %s\n", path)
    return 1
}

Populate directories lazily

Null parent adds a root row. To populate a directory lazily, append its children, then mark that directory loaded; a loaded flag is application bookkeeping, not a filesystem scan.

Read selection and paths

tree_selection returns a borrowed selection object; tree_selected_iter returns an owned iterator, or null for no selection. tree_iter_path and tree_selected_path return owned text released with Gui:text_free. Clear operations invalidate iterators for removed rows. Never keep an iterator across tree_clear or deletion of its row.