Filters are used to require nouns to have specific kinds or attributes, or to have specific scoping rules: they correspond to Inform 6's |noun=Routine| and |scope=Routine| tokens. Though these are quite different concepts in I6, their common handling seems natural in I7.
typedef struct noun_filter_token { struct parse_node *the_filter; struct parse_node *nft_created_at; int global_scope_flag; int any_things_flag; int parse_using_gpr; int nft_compiled; struct inter_name *nft_iname; CLASS_DEFINITION } noun_filter_token;
- The structure noun_filter_token is private to this section.
§2. There are only three things we can do with these: create them, compile their names (used as I6 tokens), and compile their routines.
noun_filter_token *UnderstandFilterTokens::nft_new(parse_node *spec, int global_scope, int any_things) { noun_filter_token *nft = CREATE(noun_filter_token); nft->the_filter = spec; nft->global_scope_flag = global_scope; nft->any_things_flag = any_things; nft->nft_created_at = current_sentence; nft->parse_using_gpr = FALSE; nft->nft_compiled = FALSE; if (global_scope) { package_request *PR = Hierarchy::local_package(SCOPE_FILTERS_HAP); nft->nft_iname = Hierarchy::make_iname_in(SCOPE_FILTER_FN_HL, PR); } else { package_request *PR = Hierarchy::local_package(NOUN_FILTERS_HAP); nft->nft_iname = Hierarchy::make_iname_in(NOUN_FILTER_FN_HL, PR); } return nft; } inter_name *UnderstandFilterTokens::nft_compile_routine_iname(noun_filter_token *nft) { return nft->nft_iname; } void UnderstandFilterTokens::nft_compile_routine(noun_filter_token *nft) { parse_node *noun_var = Lvalues::new_actual_NONLOCAL_VARIABLE(Inter_noun_VAR); kind *R = Specifications::to_kind(nft->the_filter); kind *K = NonlocalVariables::kind(Inter_noun_VAR); NonlocalVariables::set_kind(Inter_noun_VAR, R); if (Kinds::Behaviour::is_object(R) == FALSE) nft->parse_using_gpr = TRUE; packaging_state save = Functions::begin(nft->nft_iname); if (nft->parse_using_gpr) { inter_symbol *v_s = LocalVariables::new_internal_commented_as_symbol(I"v", I"value parsed"); inter_symbol *n_s = LocalVariables::new_internal_commented_as_symbol(I"n", I"saved value of noun"); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_symbol(K_value, v_s); inter_name *gpr_to_ask = RTKindConstructors::get_explicit_I6_GPR_iname(R); if (gpr_to_ask == NULL) gpr_to_ask = RTKindConstructors::get_kind_GPR_iname(R); EmitCode::call(gpr_to_ask); EmitCode::up(); EmitCode::inv(IF_BIP); EmitCode::down(); EmitCode::inv(EQ_BIP); EmitCode::down(); EmitCode::val_symbol(K_value, v_s); EmitCode::val_iname(K_object, Hierarchy::find(GPR_NUMBER_HL)); EmitCode::up(); EmitCode::code(); EmitCode::down(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_symbol(K_value, n_s); EmitCode::val_iname(K_object, Hierarchy::find(NOUN_HL)); EmitCode::up(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_iname(K_object, Hierarchy::find(NOUN_HL)); EmitCode::val_iname(K_object, Hierarchy::find(PARSED_NUMBER_HL)); EmitCode::up(); EmitCode::inv(IF_BIP); EmitCode::down(); EmitCode::inv(NOT_BIP); EmitCode::down(); CompilePropositions::to_test_if_variable_matches(noun_var, nft->the_filter); EmitCode::up(); EmitCode::code(); EmitCode::down(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_symbol(K_value, v_s); EmitCode::val_iname(K_object, Hierarchy::find(GPR_FAIL_HL)); EmitCode::up(); EmitCode::up(); EmitCode::up(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_iname(K_object, Hierarchy::find(NOUN_HL)); EmitCode::val_symbol(K_value, n_s); EmitCode::up(); EmitCode::up(); EmitCode::up(); EmitCode::inv(RETURN_BIP); EmitCode::down(); EmitCode::val_symbol(K_value, v_s); EmitCode::up(); } else if (nft->global_scope_flag) { inter_symbol *obj_s = LocalVariables::new_internal_commented_as_symbol(I"obj", I"object loop variable"); inter_symbol *o2_s = LocalVariables::new_internal_commented_as_symbol(I"o2", I"saved value of noun"); EmitCode::inv(SWITCH_BIP); EmitCode::down(); EmitCode::val_iname(K_object, Hierarchy::find(SCOPE_STAGE_HL)); EmitCode::code(); EmitCode::down(); EmitCode::inv(CASE_BIP); EmitCode::down(); EmitCode::val_number(1); EmitCode::code(); EmitCode::down(); if (nft->any_things_flag) EmitCode::rtrue(); else EmitCode::rfalse(); EmitCode::up(); EmitCode::up(); EmitCode::inv(CASE_BIP); EmitCode::down(); EmitCode::val_number(2); EmitCode::code(); EmitCode::down(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_symbol(K_value, obj_s); EmitCode::val_iname(K_object, Hierarchy::find(NOUN_HL)); EmitCode::up(); EmitCode::inv(OBJECTLOOP_BIP); EmitCode::down(); EmitCode::ref_iname(K_object, Hierarchy::find(NOUN_HL)); EmitCode::val_iname(K_value, RTKindDeclarations::iname(K_object)); CompilePropositions::to_test_if_variable_matches(noun_var, nft->the_filter); EmitCode::code(); EmitCode::down(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_symbol(K_value, o2_s); EmitCode::val_iname(K_object, Hierarchy::find(NOUN_HL)); EmitCode::up(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_iname(K_object, Hierarchy::find(NOUN_HL)); EmitCode::val_symbol(K_value, obj_s); EmitCode::up(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_iname(K_object, Hierarchy::find(SUPPRESS_SCOPE_LOOPS_HL)); EmitCode::val_true(); EmitCode::up(); EmitCode::call(Hierarchy::find(PLACEINSCOPE_HL)); EmitCode::down(); EmitCode::val_symbol(K_value, o2_s); EmitCode::val_true(); EmitCode::up(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_iname(K_object, Hierarchy::find(SUPPRESS_SCOPE_LOOPS_HL)); EmitCode::val_false(); EmitCode::up(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_iname(K_object, Hierarchy::find(NOUN_HL)); EmitCode::val_symbol(K_value, o2_s); EmitCode::up(); EmitCode::up(); EmitCode::up(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_iname(K_object, Hierarchy::find(NOUN_HL)); EmitCode::val_symbol(K_value, obj_s); EmitCode::up(); EmitCode::up(); EmitCode::up(); EmitCode::inv(CASE_BIP); EmitCode::down(); EmitCode::val_number(3); EmitCode::code(); EmitCode::down(); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_iname(K_object, Hierarchy::find(NEXTBEST_ETYPE_HL)); EmitCode::val_iname(K_object, Hierarchy::find(NOTINCONTEXTPE_HL)); EmitCode::up(); EmitCode::inv(RETURN_BIP); EmitCode::down(); EmitCode::val_number((inter_ti) (-1)); EmitCode::up(); EmitCode::up(); EmitCode::up(); EmitCode::up(); EmitCode::up(); } else { inter_symbol *x_s = LocalVariables::new_internal_commented_as_symbol(I"x", I"saved value of noun"); EmitCode::inv(STORE_BIP); EmitCode::down(); EmitCode::ref_symbol(K_value, x_s); EmitCode::val_iname(K_object, Hierarchy::find(NOUN_HL)); EmitCode::up(); EmitCode::inv(RETURN_BIP); EmitCode::down(); if (Specifications::to_proposition(nft->the_filter)) { TypecheckPropositions::type_check(Specifications::to_proposition(nft->the_filter), TypecheckPropositions::tc_no_problem_reporting()); CompilePropositions::to_test_as_condition( noun_var, Specifications::to_proposition(nft->the_filter)); } else CompilePropositions::to_test_if_variable_matches(noun_var, nft->the_filter); EmitCode::up(); } Functions::end(save); NonlocalVariables::set_kind(Inter_noun_VAR, K); }
§3. Access via ID. For now, though, these are perhaps strangely accessed by ID number. (Because the parse_node structure can't conveniently be annotated with pointers, that's why.)
void UnderstandFilterTokens::compile_id(noun_filter_token *nft) { if (nft) { if (nft->parse_using_gpr) EmitCode::val_iname(K_value, Hierarchy::find(GPR_TT_HL)); else if (nft->global_scope_flag) EmitCode::val_iname(K_value, Hierarchy::find(SCOPE_TT_HL)); else EmitCode::val_iname(K_value, Hierarchy::find(ROUTINEFILTER_TT_HL)); EmitCode::val_iname(K_value, nft->nft_iname); } } void UnderstandFilterTokens::emit_id(noun_filter_token *nft) { if (nft) { inter_ti annot = 0; if (nft->parse_using_gpr == FALSE) { if (nft->global_scope_flag) annot = SCOPE_FILTER_IANN; else annot = NOUN_FILTER_IANN; } inter_name *iname = UnderstandFilterTokens::nft_compile_routine_iname(nft); if (annot != 0) if (Produce::read_annotation(iname, annot) != 1) Produce::annotate_i(iname, annot, 1); EmitArrays::iname_entry(iname); } }
§4. Compiling everything. Having referred to these filter routines, we need to compile them.
void UnderstandFilterTokens::compile(void) { noun_filter_token *nft; LOOP_OVER(nft, noun_filter_token) if (nft->nft_compiled == FALSE) { current_sentence = nft->nft_created_at; UnderstandFilterTokens::nft_compile_routine(nft); nft->nft_compiled = TRUE; } }