Nested function support (bug #35772) * src/oct-parse.yy (push_fcn_symtab, recover_from_parsing_function) (eval_string): Keep track of a stack of nested functions. (parse_fcn_file): Keep track of a stack of nested functions and remove warning that nested functions are not supported. (frob_function): Call symbol_table::install_nestfunction for nested functions. (finish_function): Call symbol_table::update_nest on top level functions. * src/ov-fcn-handle.cc (octave_fcn_handle::octave_fcn_handle): Error when creating a handle to a nested function. * src/ov-usr-fcn.cc (octave_user_function::octave_user_function): Initialize new members. (octave_user_function::do_multi_index_op): Use active_context to determine execution context. * src/ov-usr-fcn.h (octave_user_function::active_context, octave_user_function::is_nested_function, octave_user_function::mark_as_nested_function): New functions. * src/pt-id.h (symbol_table::xsym): Check symbol validity. * src/symtab.cc (symbol_table::symbol_record::symbol_record_rep::active_context, symbol_table::install_nestfunction, symbol_table::do_update_nest): New functions. (symbol_table::symbol_record::symbol_record_rep::dump): Use varval () instead of varval (current_context). (symbol_table::fcn_info::fcn_info_rep::xfind, symbol_table::fcn_info::fcn_info_rep::x_builtin_find): Allow for parents of parents in subfunction search. * src/symtab.h (symbol_table::symbol_record::symbol_record_rep::symbol_record_rep, symbol_table::symbol_record::symbol_record): New parameter, decl_scope. (symbol_table::symbol_record::symbol_record_rep::force_variable, symbol_table::symbol_record::force_variable, symbol_table::symbol_record::symbol_record_rep::varref, symbol_table::symbol_record::varref, symbol_table::symbol_record::symbol_record_rep::varval, symbol_table::symbol_record::varval, symbol_table::symbol_record::symbol_record_rep::is_defined, symbol_table::symbol_record::is_defined, symbol_table::symbol_record::symbol_record_rep::is_variable, symbol_table::symbol_record::is_variable, symbol_table::symbol_record::varval, symbol_table::symbol_record::symbol_record_rep::varval): Use xdefault_context. symbol_table::symbol_record::symbol_record_rep::push_context, symbol_table::symbol_record::push_context, symbol_table::symbol_record::symbol_record_rep::pop_context, symbol_table::symbol_record::pop_context, symbol_table::symbol_record::symbol_record_rep::clear, symbol_table::symbol_record::clear): Only work when the decl_scope of the symbol is the active scope. (symbol_table::symbol_record::symbol_record_rep::is_valid, symbol_table::symbol_record::is_valid, symbol_table::symbol_record::symbol_record_rep::invalidate, symbol_table::symbol_record::invalidate, symbol_table::symbol_record::symbol_record_rep::set_curr_fcn, symbol_table::symbol_record::set_curr_fcn, symbol_table::symbol_record::symbol_record_rep::scope, symbol_table::symbol_record::scope, symbol_table::symbol_record::active_context, symbol_table::update_nest, symbol_table::symbol_table, symbol_table::add_nest_child, symbol_table::look_nonlocal): New functions. (symbol_table::symbol_record::symbol_record_rep::init_persistent): Init to xdefault_context instead of xcurrent_context. (symbol_table::symbol_record::symbol_record_rep::dup, symbol_table::symbol_record::dup): New parameter, scope. (symbol_table::set_scope, symbol_table::dup_scope, symbol_table:;get_instance): Pass scope_id to symbol_table constructor. (symbol_table::find_symbol, symbol_table::glob_global_variables, symbol_table::regexp_global_variables): Specify scope when creating symbol_record. (symbol_table::force_variable, symbol_table::varref, symbol_table::varval, symbol_table::all_variables): Default to xdefault_context instead of xcurrent_context. (symbol_table::do_dup_scope): Pass scope of new symbol table to symbol dup. (symbol_table::do_insert): Check nest_parent for nonlocals. (symbol_table::do_push_context, symbol_table::do_pop_context, symbol_table::do_clear_variables, symbol_table::do_clear_objects, symbol_table::do_clear_variable, symbol_table::do_clear_variable_pattern, symbol_table::do_clear_variable_regexp): Pass my_scope to symbol. * test/Makefile.am: Include nest/module.mk. * test/nest/arg_nest.m: New file. * test/nest/arg_ret.m: New file. * test/nest/module.mk: New file. * test/nest/no_closure.m: New file. * test/nest/persistent_nest.m: New file. * test/nest/recursive_nest.m: New file. * test/nest/recursive_nest2.m: New file. * test/nest/recursive_nest3.m: New file. * test/nest/scope0.m: New file. * test/nest/scope1.m: New file. * test/nest/scope2.m: New file. * test/nest/scope3.m: New file. * test/nest/script_nest.m: New file. * test/nest/script_nest_script.m: New file. * test/nest/test_nest.m: New file. * test/nest/varg_nest.m: New file. * test/nest/varg_nest2.m: New file.