%-----------------------------------------------------------------------------% %-----------------------------------------------------------------------------% % % File: prog_io.nl. % Main author: fjh. % % This module defines a data structure for representing Mercury % programs. % % In some ways the representation of programs here is considerably % more complex than is necessary for the compiler. % The basic reason for this is that it was designed to preserve % as much information about the source code as possible, so that % this representation could also be used for other tools such % as Mercury-to-Goedel converters, pretty-printers, etc. % Currently the only information that is lost is the comments, % whitespace and indentation, and any redundant parenthesization. % It would be a good idea to preserve those too (well, maybe not % the redundant parentheses), but right now it's not worth the effort. % % So that means that this phase of compilation is purely parsing. % No simplifications are done. The results of this phase specify % basically the same information as is contained in the source code, % but in a parse tree rather than a flat file. % Simplifications are done only by make_hlds.nl, which transforms % the parse tree which we built here into the HLDS. % % Some of this code is a rather bad example of cut-and-paste style reuse. % It should be cleaned up to eliminate most of the duplication. % But that task really needs to wait until we implement higher-order % predicates. For the moment, just be careful that any changes % you make are reflected correctly in all similar parts of this % file. % XXX todo: % % 1. implement importing/exporting operators with a particular fixity % eg. :- import_op prefix(+). % only prefix +, not infix % (not important, but should be there for reasons of symmetry.) % 2. improve the handling of type and inst parameters % (see XXX's below) % 3. improve the error reporting % % Question: should we allow `:- rule' declarations??? %-----------------------------------------------------------------------------% %-----------------------------------------------------------------------------% :- module prog_io. :- interface. :- import_module string, int, list, varset, term, io. %-----------------------------------------------------------------------------% % This is how programs (and parse errors) are represented. :- type message_list == list(pair(string, term)). % the error/warning message, and the % term to which it relates :- type program ---> module( module_name, item_list ). :- type item_list == list(item_and_context). :- type item_and_context == pair(item, term__context). :- type item ---> clause(varset, sym_name, list(term), goal) % VarNames, PredName, HeadArgs, ClauseBody ; type_defn(varset, type_defn, condition) ; inst_defn(varset, inst_defn, condition) ; mode_defn(varset, mode_defn, condition) ; module_defn(varset, module_defn) ; pred(varset, sym_name, list(type_and_mode), determinism, condition) % VarNames, PredName, ArgTypes, % Deterministicness, Cond ; rule(varset, sym_name, list(type), condition) % VarNames, PredName, ArgTypes, Cond ; mode(varset, sym_name, list(mode), determinism, condition) % VarNames, PredName, ArgModes, % Deterministicness, Cond ; nothing. % used for items that should be ignored % (currently only NU-Prolog `when' declarations, % which are silently ignored for backwards % compatibility). :- type type_and_mode ---> type_only(type) ; type_and_mode(type, mode). :- type determinism ---> det ; semidet ; nondet ; unspecified. %-----------------------------------------------------------------------------% % Here's how clauses and goals are represented. % (Constructs like "=>", "<=", and "<=>" are considered to be % just higher-order predicates, and so aren't represented % specially here.) % clause/4 defined above :- type goal ---> (goal,goal) ; fail % could use conj(goals) instead ; {goal;goal} % {...} quotes ';'/2. ; true % could use disj(goals) instead ; not(vars,goal) ; some(vars,goal) ; all(vars,goal) ; if_then(vars,goal,goal) ; if_then_else(vars,goal,goal,goal) ; call(term) ; unify(term, term). :- type goals == list(goal). :- type vars == list(variable). %-----------------------------------------------------------------------------% % This is how types are represented. % one day we might allow types to take % value parameters as well as type parameters. % type_defn/3 define above :- type type_defn ---> du_type(sym_name, list(type_param), list(constructor)) ; uu_type(sym_name, list(type_param), list(type)) ; eqv_type(sym_name, list(type_param), type) ; abstract_type(sym_name, list(type_param)). :- type constructor == pair(sym_name, list(type)). % XXX should type parameters be variables not terms ?? :- type type_param == term. :- type (type) == term. % Types may have arbitrary assertions associated with them % (eg. you can define a type which represents sorted lists). % The compiler will ignore these assertions - they are intended % to be used by other tools, such as the debugger. :- type condition ---> true ; where(term). %-----------------------------------------------------------------------------% % This is how instantiatednesses and modes are represented. % Note that while we use the normal term data structure to represent % type terms (see above), we need a separate data structure for inst % terms. % inst_defn/3 defined above :- type inst_defn ---> inst_defn(sym_name, list(inst_param), inst). % XXX should inst parameters be variables not terms ?? :- type inst_param == term. :- type (inst) ---> free ; bound(list(bound_inst)) ; ground ; inst_var(variable) ; user_defined_inst(sym_name, list(inst)). :- type bound_inst ---> functor(const, list(inst)). % mode_defn/3 defined above :- type mode_defn ---> mode_defn(sym_name, list(inst_param), mode). :- type (mode) ---> ((inst) -> (inst)) ; user_defined_mode(sym_name, list(inst)). % mode/4 defined above %-----------------------------------------------------------------------------% % This is how module-system declarations (such as imports % and exports) are represented. :- type module_defn ---> module(module_name) ; interface ; implementation ; end_module(module_name) ; export(sym_list) ; import(sym_list) ; use(sym_list). :- type sym_list ---> sym(list(sym_specifier)) ; pred(list(pred_specifier)) ; cons(list(pred_specifier)) ; op(list(op_specifier)) ; adt(list(sym_name_specifier)) ; type(list(sym_name_specifier)) ; module(list(module_specifier)). :- type sym_specifier ---> sym(sym_name_specifier) ; typed_sym(typed_cons_specifier) ; pred(pred_specifier) ; cons(cons_specifier) ; op(op_specifier) ; adt(sym_name_specifier) ; type(sym_name_specifier) ; module(module_specifier). :- type pred_specifier ---> sym(sym_name_specifier) ; name_args(sym_name, list(type)). :- type cons_specifier ---> sym(sym_name_specifier) ; typed(typed_cons_specifier). :- type typed_cons_specifier ---> name_args(sym_name, list(type)) ; name_res(sym_name_specifier, type) ; name_args_res(sym_name, list(type), type). :- type op_specifier ---> sym(sym_name_specifier) % XXX operator fixity specifiers not yet implemented ; fixity(sym_name_specifier, fixity). :- type fixity ---> infix ; prefix ; postfix. :- type sym_name_specifier ---> name(sym_name) ; name_arity(sym_name, integer). :- type sym_name ---> unqualified(string) ; qualified(module_specifier, string). :- type module_specifier == string. :- type module_name == string. %-----------------------------------------------------------------------------% % This module (prog_io) exports the following predicate: :- pred prog_io__read_program(string, bool, message_list, item_list, io__state, io__state). :- mode prog_io__read_program(input, output, output, output, di, uo). % read_program(ModuleName, Error, Messages, Program) % - reads and parses the module 'ModuleName'. Error is `yes' % if a syntax error was detected and `no' otherwise, % Messages is a list of warning/error messages, % and Program is the parse tree. %-----------------------------------------------------------------------------% %-----------------------------------------------------------------------------% :- implementation. %-----------------------------------------------------------------------------% % When actually reading in type declarations, we need to % check for errors. :- type maybe(T) ---> error(string, term) ; ok(T). :- type maybe2(T1, T2) ---> error(string, term) ; ok(T1, T2). :- type maybe_functor == maybe2(sym_name, list(term)). :- type maybe_item_and_context == maybe2(item, term__context). % This implementation uses io__read_term to read in the program % term at a time, and then converts those terms into clauses and % declarations, checking for errors as it goes. % Note that rather than using difference lists, we just % build up the lists of items and messages in reverse order % and then reverse them afterwards. (Using difference lists would require % late-input modes.) prog_io__read_module(Module, Error, Messages, Prog) --> % io__op(1199, fx, "rule"), % io__op(1179, xfy, "--->"), % XXX should be automatic { string__append(Module, ".nl", FileName) }, io__see(FileName, R), (if { R = ok } then read_all_items(RevMessages, RevItems0, Error0), { get_end_module(RevItems0, RevItems, EndModule), reverse(RevMessages, Messages0), reverse(RevItems, Items0), check_begin_module(Messages0, Items0, Error0, EndModule, Messages, Items, Error), Prog = module(Module, Items) }, io__seen else io__progname(Progname), { string__append(Progname, ": can't open file '", Message1), string__append(Message1, FileName, Message2), string__append(Message2, "'.\n", Message), dummy_term(Term), Messages = [Message - Term], Error = yes, Prog = module(Module, []) } ). %-----------------------------------------------------------------------------% % extract the final `:- end_module' declaration if any :- type module_end ---> no ; yes(module_name, term__context). :- pred get_end_module(item_list, item_list, module_end). :- mode get_end_module(input, output, output). get_end_module(RevItems0, RevItems, EndModule) :- (if some [VarSet, ModuleName, RevItems1] RevItems0 = [ module_defn(VarSet, end_module(ModuleName)) - Context | RevItems1] then RevItems = RevItems1, EndModule = yes(ModuleName, Context) else RevItems = RevItems0, EndModule = no ). %-----------------------------------------------------------------------------% % check that the module starts with a :- module declaration, % and that the end_module declaration (if any) is correct, % and construct the final parsing result. :- pred check_begin_module(message_list, item_list, bool, module_end, message_list, item_list, bool). :- mode check_begin_module(input, input, input, input, output, output, output). check_begin_module(Messages0, Items0, Error0, EndModule, Messages, Items, Error) :- % check that the first item is a `:- module ModuleName' % declaration (if some [VarSet, ModuleName1, Items1, Context] Items0 = [module_defn(VarSet, module(ModuleName1)) - Context | Items1] then % check that the end module declaration (if any) % matches the begin module declaration (if some [ModuleName2, Context2] ( EndModule = yes(ModuleName2, Context2), not ModuleName1 = ModuleName2 ) then dummy_term_with_context(Context2, Term), ThisError = "`:- end_module' declaration doesn't match `:- module' declaration" - Term, append([ThisError], Messages0, Messages), Items = Items1, Error = yes else Messages = Messages0, Items = Items1, Error = Error0 ) else dummy_term(Term2), ThisError = "module should start with a `:- module' declaration" - Term2, Messages = [ThisError | Messages0], Items = Items0, Error = yes ). % Create a dummy term. % Used for error messages that are not associated with any % particular term or context. :- pred dummy_term(term). :- mode dummy_term(output). dummy_term(Term) :- term__context_init(0, Context), dummy_term_with_context(Context, Term). % Create a dummy term with the specified context. % Used for error messages that are associated with some specific % context, but for which we don't want to print out the term % (or for which the term isn't available to be printed out). :- pred dummy_term_with_context(term__context, term). :- mode dummy_term_with_context(input, output). dummy_term_with_context(Context, Term) :- Term = term_functor(term_atom(""), [], Context). %-----------------------------------------------------------------------------% % Read a source file from standard input, first reading in % the input term by term and then parsing those terms and producing % a high-level representation. % Parsing is actually a 3-stage process instead of the % normal two-stage process: % lexical analysis (chars -> tokens), % parsing stage 1 (tokens -> terms), % parsing stage 2 (terms -> items). % The final stage produces a list of program items, each of % which may be a declaration or a clause. :- pred read_all_items(message_list, item_list, bool, io__state, io__state). :- mode read_all_items(output, output, output, di, uo). read_all_items(Messages, Items, Error) --> read_items_loop([], [], no, Messages, Items, Error). %-----------------------------------------------------------------------------% % The loop is arranged somewhat carefully: we want it to % be tail recursive, and we want to do a small garbage collection % after we have read each item to minimize memory usage % and improve cache locality. So each iteration calls % read_item(MaybeItem) - which does all the work for a single item - % via io__gc_call/1, which calls the goal with garbage collection. % This manual garbage collection won't be strictly necessary % when (if) we implement automatic garbage collection, but % it will probably still improve performance. % % Note: the following will NOT be tail recursive with our % implementation unless the compiler is smart enough to inline % read_items_loop_2. :- pred read_items_loop(message_list, list(item), bool, message_list, list(item), bool, io__state, io__state). :- mode read_items_loop(input, input, input, output, output, output, di, uo). read_items_loop(Msgs1, Items1, Error1, Msgs, Items, Error) --> io__gc_call(read_item(MaybeItem)), read_items_loop_2(MaybeItem, Msgs1, Items1, Error1, Msgs, Items, Error). %-----------------------------------------------------------------------------% :- pred read_items_loop_2(maybe_item_or_eof, message_list, list(item), bool, message_list, list(item), bool, io__state, io__state). :- mode read_items_loop_2(input, input, input, input, output, output, output, di, uo). % do a switch on the type of the next item read_items_loop_2(eof, Msgs, Items, Error, Msgs, Items, Error) --> []. % if the next item was end-of-file, then we're done. read_items_loop_2(syntax_error(ErrorMsg), Msgs0, Items0, _Error0, Msgs, Items, Error) --> % if the next item was a syntax error, then insert it in % the list of messages and continue looping io__input_stream(Stream), io__stream_name(Stream, StreamName), % XXX the line number is slightly off io__get_line_number(LineNumber), { term__context_init(StreamName, LineNumber, Context), dummy_term_with_context(Context, Term), ThisError = ErrorMsg - Term, Msgs1 = [ThisError | Msgs0], Items1 = Items0, Error1 = yes }, read_items_loop(Msgs1, Items1, Error1, Msgs, Items, Error). read_items_loop_2(error(M,T), Msgs0, Items0, _Error0, Msgs, Items, Error) --> % if the next item was a semantic error, then insert it in % the list of messages and continue looping { add_error(M, T, Msgs0, Msgs1), Items1 = Items0, Error1 = yes }, read_items_loop(Msgs1, Items1, Error1, Msgs, Items, Error). read_items_loop_2(ok(Item, Context), Msgs0, Items0, Error0, Msgs, Items, Error) --> % if the next item was a valid item, then insert it in % the list of items and continue looping { Msgs1 = Msgs0, Items1 = [Item - Context | Items0], Error1 = Error0 }, read_items_loop(Msgs1, Items1, Error1, Msgs, Items, Error). %-----------------------------------------------------------------------------% % read_item/1 reads a single item, and if it is a valid term % parses it. :- type maybe_item_or_eof ---> eof ; syntax_error(string) ; error(string, term) ; ok(item, term__context). :- pred read_item(maybe_item_or_eof, io__state, io__state). :- mode read_item(output, di, uo). read_item(MaybeItem) --> io__read_term(MaybeTerm), { process_read_term(MaybeTerm, MaybeItem) }. :- pred process_read_term(read_term, maybe_item_or_eof). :- mode process_read_term(input, output). process_read_term(eof, eof). process_read_term(error(ErrorMsg), syntax_error(ErrorMsg)). process_read_term(term(VarSet, Term), MaybeItemOrEof) :- parse_item(VarSet, Term, MaybeItem), convert_item(MaybeItem, MaybeItemOrEof). :- pred convert_item(maybe_item_and_context, maybe_item_or_eof). :- mode convert_item(input, output). convert_item(ok(Item, Context), ok(Item, Context)). convert_item(error(M,T), error(M,T)). :- pred parse_item(varset, term, maybe_item_and_context). :- mode parse_item(input, input, output). parse_item(VarSet, Term, Result) :- (if some [Decl, Context] Term = term_functor(term_atom(":-"), [Decl], Context) then parse_decl(VarSet, Decl, R), add_context(R, Context, Result) else % OK, it's not a declaration. Is it a fact, or a rule? (if some [H, B, Context2] Term = term_functor(term_atom(":-"), [H,B], Context2) then % it's a rule Head = H, Body = B, TheContext = Context2 else % it's a fact Head = Term, (if some [Functor, Args, Context3] Head = term_functor(Functor, Args, Context3) then TheContext = Context3 else % term consists of just a single % variable - the context has been lost term__context_init(0, TheContext) ), Body = term_functor(term_atom("true"), [], TheContext) ), parse_goal(Body, Body2), parse_qualified_term(Head, "clause head", R), process_clause(R, VarSet, Body2, R2), add_context(R2, TheContext, Result) ). :- pred add_context(maybe(item), term__context, maybe_item_and_context). :- mode add_context(input, input, output). add_context(error(M, T), _, error(M, T)). add_context(ok(Item), Context, ok(Item, Context)). :- pred process_clause(maybe_functor, varset, goal, maybe(item)). :- mode process_clause(input, input, input, output). process_clause(ok(Name, Args), VarSet, Body, ok(clause(VarSet, Name, Args, Body))). process_clause(error(ErrMessage, Term), _, _, error(ErrMessage, Term)). :- pred join_error(bool, bool, bool). :- mode join_error(input, input, output). join_error(yes, _, yes). join_error(no, Error, Error). %-----------------------------------------------------------------------------% % Parse a goal. % We just check if it matches the appropriate pattern % for one of the builtins. If it doens't match any of the % builtins, then it's just a predicate call. % XXX we should do more parsing here - type qualification and % module qualification should be parsed here. :- pred parse_goal(term, goal). :- mode parse_goal(input, output). parse_goal(Term, Goal) :- (if some [Goal2] parse_goal_2(Term, Goal2) then Goal = Goal2 else Goal = call(Term) ). :- pred parse_goal_2(term, goal). :- mode parse_goal_2(input, output). parse_goal_2(term_functor(term_atom("true"),[],_), true). parse_goal_2(term_functor(term_atom("fail"),[],_), fail). parse_goal_2(term_functor(term_atom("="),[A,B],_), unify(A,B)). parse_goal_2(term_functor(term_atom("->"),[A0,B0],_), if_then(Vars,A,B)) :- parse_some_vars_goal(A0, Vars, A), parse_goal(B0, B). parse_goal_2(term_functor(term_atom(","),[A0,B0],_), (A,B)) :- parse_goal(A0, A), parse_goal(B0, B). parse_goal_2(term_functor(term_atom(";"),[A0,B0],_), R) :- (if some [X0, Y0, Context] A0 = term_functor(term_atom("->"), [X0,Y0], Context) then parse_some_vars_goal(X0, Vars, X), parse_goal(Y0, Y), parse_goal(B0, B), R = if_then_else(Vars, X, Y, B) else parse_goal(A0, A), parse_goal(B0, B), R = (A;B) ). parse_goal_2(term_functor(term_atom("if"), [term_functor(term_atom("then"),[A0,B0],_)],_), if_then(Vars,A,B)) :- parse_some_vars_goal(A0, Vars, A), parse_goal(B0, B). parse_goal_2( term_functor(term_atom("else"),[ term_functor(term_atom("if"),[ term_functor(term_atom("then"),[A0,B0],_) ],_), C0 ],_), if_then_else(Vars,A,B,C)) :- parse_some_vars_goal(A0, Vars, A), parse_goal(B0, B), parse_goal(C0, C). parse_goal_2( term_functor(term_atom("not"), [A0], _), not([],A) ) :- parse_goal(A0, A). parse_goal_2( term_functor(term_atom("\+"), [A0], _), not([],A) ) :- parse_goal(A0, A). parse_goal_2( term_functor(term_atom("all"),[Vars0,A0],_),all(Vars,A) ):- term__vars(Vars0, Vars), parse_goal(A0, A). parse_goal_2( term_functor(term_atom("some"),[Vars0,A0],_),some(Vars,A) ):- term__vars(Vars0, Vars), parse_goal(A0, A). :- pred parse_some_vars_goal(term, vars, goal). :- mode parse_some_vars_goal(input, output, output). parse_some_vars_goal(A0, Vars, A) :- (if some [Vars0, A1, Context] A0 = term_functor(term_atom("some"), [Vars0,A1], Context) then term__vars(Vars0, Vars), parse_goal(A1, A) else Vars = [], parse_goal(A0, A) ). %-----------------------------------------------------------------------------% % parse a declaration :- pred parse_decl(varset, term, maybe(item)). :- mode parse_decl(input, input, output). parse_decl(VarSet, F, Result) :- (if some [Atom, As, Context] F = term_functor(term_atom(Atom), As, Context) then (if some [R] process_decl(VarSet, Atom, As, R) then Result = R else Result = error("unrecognized declaration", F) ) else Result = error("atom expected after `:-'", F) ). % process_decl(VarSet, Atom, Args, Result) succeeds if Atom(Args) % is a declaration and binds Result to a representation of that % declaration. :- pred process_decl(varset, string, list(term), maybe(item)). :- mode process_decl(input, input, input, output). process_decl(VarSet, "type", [TypeDecl], Result) :- parse_type_decl(VarSet, TypeDecl, Result). process_decl(VarSet, "pred", [PredDecl], Result) :- parse_type_decl_pred(VarSet, PredDecl, Result). /*** OBSOLETE process_decl(VarSet, "rule", [RuleDecl], Result) :- parse_type_decl_rule(VarSet, RuleDecl, Result). ***/ process_decl(VarSet, "mode", [ModeDecl], Result) :- parse_mode_decl(VarSet, ModeDecl, Result). process_decl(VarSet, "inst", [InstDecl], Result) :- parse_inst_decl(VarSet, InstDecl, Result). process_decl(VarSet, "import_module", [ModuleSpec], Result) :- parse_import_module_decl(VarSet, ModuleSpec, Result). process_decl(VarSet, "use_module", [ModuleSpec], Result) :- parse_use_module_decl(VarSet, ModuleSpec, Result). process_decl(VarSet, "export_module", [ModuleSpec], Result) :- parse_export_module_decl(VarSet, ModuleSpec, Result). process_decl(VarSet, "import_sym", [SymSpec], Result) :- parse_import_sym_decl(VarSet, SymSpec, Result). process_decl(VarSet, "use_sym", [SymSpec], Result) :- parse_use_sym_decl(VarSet, SymSpec, Result). process_decl(VarSet, "export_sym", [SymSpec], Result) :- parse_export_sym_decl(VarSet, SymSpec, Result). process_decl(VarSet, "import_pred", [PredSpec], Result) :- parse_import_pred_decl(VarSet, PredSpec, Result). process_decl(VarSet, "use_pred", [PredSpec], Result) :- parse_use_pred_decl(VarSet, PredSpec, Result). process_decl(VarSet, "export_pred", [PredSpec], Result) :- parse_export_pred_decl(VarSet, PredSpec, Result). process_decl(VarSet, "import_cons", [ConsSpec], Result) :- parse_import_cons_decl(VarSet, ConsSpec, Result). process_decl(VarSet, "use_cons", [ConsSpec], Result) :- parse_use_cons_decl(VarSet, ConsSpec, Result). process_decl(VarSet, "export_cons", [ConsSpec], Result) :- parse_export_cons_decl(VarSet, ConsSpec, Result). process_decl(VarSet, "import_type", [TypeSpec], Result) :- parse_import_type_decl(VarSet, TypeSpec, Result). process_decl(VarSet, "use_type", [TypeSpec], Result) :- parse_use_type_decl(VarSet, TypeSpec, Result). process_decl(VarSet, "export_type", [TypeSpec], Result) :- parse_export_type_decl(VarSet, TypeSpec, Result). process_decl(VarSet, "import_adt", [ADT_Spec], Result) :- parse_import_adt_decl(VarSet, ADT_Spec, Result). process_decl(VarSet, "use_adt", [ADT_Spec], Result) :- parse_use_adt_decl(VarSet, ADT_Spec, Result). process_decl(VarSet, "export_adt", [ADT_Spec], Result) :- parse_export_adt_decl(VarSet, ADT_Spec, Result). process_decl(VarSet, "import_op", [OpSpec], Result) :- parse_import_op_decl(VarSet, OpSpec, Result). process_decl(VarSet, "use_op", [OpSpec], Result) :- parse_use_op_decl(VarSet, OpSpec, Result). process_decl(VarSet, "export_op", [OpSpec], Result) :- parse_export_op_decl(VarSet, OpSpec, Result). process_decl(VarSet, "interface", [], ok(module_defn(VarSet, interface))). process_decl(VarSet, "implementation", [], ok(module_defn(VarSet, implementation))). process_decl(VarSet, "module", [ModuleName], Result) :- (if some [Module, Context] ModuleName = term_functor(term_atom(Module), [], Context) then Result = ok(module_defn(VarSet, module(Module))) else Result = error("module name expected", ModuleName) ). process_decl(VarSet, "end_module", [ModuleName], Result) :- (if some [Module, Context] ModuleName = term_functor(term_atom(Module), [], Context) then Result = ok(module_defn(VarSet, end_module(Module))) else Result = error("module name expected", ModuleName) ). % NU-Prolog `when' declarations are silently ignored for % backwards compatibility. process_decl(_VarSet, "when", [_Goal, _Cond], Result) :- Result = ok(nothing). :- pred parse_type_decl(varset, term, maybe(item)). :- mode parse_type_decl(input, input, output). parse_type_decl(VarSet, TypeDecl, Result) :- (if some [R, Cond] parse_type_decl_type(TypeDecl, Cond, R) then R1 = R, Cond1 = Cond else process_abstract_type(TypeDecl, R1), Cond1 = true ), parse_type_decl_2(R1, VarSet, Cond1, Result). :- pred parse_type_decl_2(maybe(type_defn), varset, condition, maybe(item)). :- mode parse_type_decl_2(input, input, input, output). parse_type_decl_2(error(Error, Term), _, _, error(Error, Term)). parse_type_decl_2(ok(TypeDefn), VarSet, Cond, ok(type_defn(VarSet, TypeDefn, Cond))). % we should check the condition for errs % (don't bother at the moment, since we ignore % conditions anyhow :-) %-----------------------------------------------------------------------------% % add a warning message to the list of messages :- pred add_warning(string, term, message_list, message_list). :- mode add_warning(input, input, output, input). add_warning(Warning, Term, [Msg - Term | Msgs], Msgs) :- string__append("warning: ", Warning, Msg). % add an error message to the list of messages :- pred add_error(string, term, message_list, message_list). :- mode add_error(input, input, input, output). add_error(Error, Term, Msgs, [Msg - Term | Msgs]) :- string__append("error: ", Error, Msg). %-----------------------------------------------------------------------------% % parse_type_decl_type(Term, Condition, Result) succeeds % if Term is a "type" type declaration, and binds Condition % to the condition for that declaration (if any), and Result to % a representation of the declaration. :- pred parse_type_decl_type(term, condition, maybe(type_defn)). :- mode parse_type_decl_type(input, input, output). parse_type_decl_type(term_functor(term_atom("--->"),[H,B],_), Condition, R) :- get_condition(B, Body, Condition), process_du_type(H, Body, R). parse_type_decl_type(term_functor(term_atom("="),[H,B],_), Condition, R) :- get_condition(B, Body, Condition), process_uu_type(H, Body, R). parse_type_decl_type(term_functor(term_atom("=="),[H,B],_), Condition, R) :- get_condition(B, Body, Condition), process_eqv_type(H, Body, R). %-----------------------------------------------------------------------------% % parse_type_decl_pred(Pred, Condition, Result) succeeds % if Pred is a predicate type declaration, and binds Condition % to the condition for that declaration (if any), and Result to % a representation of the declaration. :- pred parse_type_decl_pred(varset, term, maybe(item)). :- mode parse_type_decl_pred(input, input, output). parse_type_decl_pred(VarSet, Pred, R) :- get_condition(Pred, Body, Condition), get_determinism(Body, Body2, Determinism), process_pred(VarSet, Body2, Determinism, Condition, R). %-----------------------------------------------------------------------------% /*** OBSOLETE % parse_type_decl_rule(VarSet, Rule, Result) succeeds % if Rule is a "rule" type declaration, and binds Result to % a representation of the declaration. % ("rule" here means DCG predicate, not horn clause.) :- pred parse_type_decl_rule(varset, term, maybe(item)). :- mode parse_type_decl_rule(input, input, output). parse_type_decl_rule(VarSet, Rule, R) :- get_condition(Rule, Body, Condition), process_mode(VarSet, Body, Condition, R). ****/ %-----------------------------------------------------------------------------% % parse_mode_decl_pred(Pred, Condition, Result) succeeds % if Pred is a predicate mode declaration, and binds Condition % to the condition for that declaration (if any), and Result to % a representation of the declaration. :- pred parse_mode_decl_pred(varset, term, maybe(item)). :- mode parse_mode_decl_pred(input, input, output). parse_mode_decl_pred(VarSet, Pred, R) :- get_condition(Pred, Body, Condition), get_determinism(Body, Body2, Determinism), process_mode(VarSet, Body2, Determinism, Condition, R). %-----------------------------------------------------------------------------% % get_determinism(Term0, Term, Determinism) binds Determinism % to a representation of the 'where' condition of Term0, if any, % and binds Term to the other part of Term0. If Term0 does not % contain a condition, then Determinism is bound to true. :- pred get_determinism(term, term, condition). :- mode get_determinism(input, output, output). get_determinism(B, Body, Determinism) :- (if some [Body1, Determinism1, Context] B = term_functor(term_atom("is"), [Body1, Determinism1], Context) then Body = Body1, (if some [Determinism2, Determinism3, Context2] ( Determinism1 = term_functor(term_atom(Determinism2), [], Context2), standard_det(Determinism2, Determinism3) ) then Determinism = Determinism3 else % XXX should report a syntax error!! Determinism = unspecified ) else Body = B, Determinism = unspecified ). :- pred standard_det(string, determinism). :- mode standard_det(input, output). standard_det("det", det). standard_det("nondet", nondet). standard_det("semidet", semidet). %-----------------------------------------------------------------------------% % get_condition(Term0, Term, Condition) binds Condition % to a representation of the 'where' condition of Term0, if any, % and binds Term to the other part of Term0. If Term0 does not % contain a condition, then Condition is bound to true. :- pred get_condition(term, term, condition). :- mode get_condition(input, output, output). get_condition(B, Body, Condition) :- (if some [Body1, Condition1, Context] B = term_functor(term_atom("where"), [Body1, Condition1], Context) then Body = Body1, Condition = where(Condition1) else Body = B, Condition = true ). %-----------------------------------------------------------------------------% % This is for "Head = Body" (undiscriminated union) definitions. :- pred process_uu_type(term, term, maybe(type_defn)). :- mode process_uu_type(input, input, output). process_uu_type(Head, Body, Result) :- check_for_errors(Head, Body, Result0), process_uu_type_2(Result0, Body, Result). :- pred process_uu_type_2(maybe_functor, term, maybe(type_defn)). :- mode process_uu_type_2(input, input, output). process_uu_type_2(error(Error, Term), _, error(Error, Term)). process_uu_type_2(ok(Name, Args), Body, ok(uu_type(Name,Args,List))) :- sum_to_list(Body, List). %-----------------------------------------------------------------------------% % This is for "Head == Body" (equivalence) definitions. :- pred process_eqv_type(term, term, maybe(type_defn)). :- mode process_eqv_type(input, input, output). process_eqv_type(Head, Body, Result) :- check_for_errors(Head, Body, Result0), process_eqv_type_2(Result0, Body, Result). :- pred process_eqv_type_2(maybe_functor, term, maybe(type_defn)). :- mode process_eqv_type_2(input, input, output). process_eqv_type_2(error(Error, Term), _, error(Error, Term)). process_eqv_type_2(ok(Name, Args), Body, ok(eqv_type(Name,Args,Body))). %-----------------------------------------------------------------------------% % process_du_type(TypeHead, TypeBody, Result) % checks that its arguments are well formed, and if they are, % binds Result to a representation of the type information about the % TypeHead. % This is for "Head ---> Body" (constructor) definitions. :- pred process_du_type(term, term, maybe(type_defn)). :- mode process_du_type(input, input, output). process_du_type(Head, Body, Result) :- check_for_errors(Head, Body, Result0), process_du_type_2(Result0, Body, Result). :- pred process_du_type_2(maybe_functor, term, maybe(type_defn)). :- mode process_du_type_2(input, input, output). process_du_type_2(error(Error, Term), _, error(Error, Term)). process_du_type_2(ok(Functor,Args), Body, Result) :- % check that body is a disjunction of constructors (if some [Constrs] convert_constructors(Body, Constrs) then Result = ok(du_type(Functor, Args, Constrs)) else Result = error("Invalid RHS of type definition", Body) ). %-----------------------------------------------------------------------------% % process_abstract_type(TypeHead, Result) % checks that its argument is well formed, and if it is, % binds Result to a representation of the type information about the % TypeHead. :- pred process_abstract_type(term, term, maybe(type_defn)). :- mode process_abstract_type(input, input, output). process_abstract_type(Head, Result) :- dummy_term(Body), check_for_errors(Head, Body, Result0), process_abstract_type_2(Result0, Result). :- pred process_abstract_type_2(maybe_functor, maybe(type_defn)). :- mode process_abstract_type_2(input, output). process_abstract_type_2(error(Error, Term), error(Error, Term)). process_abstract_type_2(ok(Functor, Args), ok(abstract_type(Functor, Args))). %-----------------------------------------------------------------------------% % check a type definition for errors :- pred check_for_errors(term, term, maybe_functor). :- mode check_for_errors(input, input, output). check_for_errors(Term, _, error("variable on LHS of type definition", Term)) :- Term = term_variable(_). check_for_errors(Term, Body, Result) :- Term = term_functor(_,_,_), parse_qualified_term(Term, "type definition", R), check_for_errors_2(R, Body, Term, Result). :- pred check_for_errors_2(maybe_functor, term, term, maybe_functor). :- mode check_for_errors_2(input, input, input, output). check_for_errors_2(error(Msg, Term), _, _, error(Msg, Term)). check_for_errors_2(ok(Name, Args), Body, Term, Result) :- check_for_errors_3(Name, Args, Body, Term, Result). :- pred check_for_errors_3(sym_name, list(term), term, term, maybe_functor). :- mode check_for_errors_3(input, input, input, input, output). check_for_errors_3(Name, Args, Body, Term, Result) :- % check that all the head args are variables (if some [Arg] ( member(Arg, Args), all [Var] Arg ~= term_variable(Var) ) then Result = error("Type parameters must be variables", Arg) else % check that all the head arg variables are distinct if some [Arg2, OtherArgs] ( member(Arg2, Args, Arg2.OtherArgs), member(Arg2, OtherArgs) ) then Result = error("Repeated type parameters in LHS of type defn", Term) else % check that all the variables in the body occur in the head if some [Var2] ( term__contains_var(Body, Var2), not term__contains_var_list(Args, Var2) ) then Result = error("Free type parameter in RHS of type definition", Var2) else Result = ok(Name, Args) ). %-----------------------------------------------------------------------------% % Convert a list of terms separated by semi-colons % (known as a "disjunction", even thought the terms aren't goals % in this case) into a list of constructors :- pred convert_constructors(term, list(constructor)). :- mode convert_constructors(input, output). convert_constructors(Body, Constrs) :- disjunction_to_list(Body, List), convert_constructors_2(List, Constrs). % true if input argument is a valid list of constructors :- pred convert_constructors_2(list(term), list(constructor)). :- mode convert_constructors_2(input, output). convert_constructors_2([], []). convert_constructors_2(Term.Terms, Constr.Constrs) :- convert_constructor(Term, Constr), convert_constructors_2(Terms, Constrs). % true if input argument is a valid constructor. % Note that as a special case, one level of % curly braces around the constructor are ignored. % This is to allow you to define ';'/2 constructors. :- pred convert_constructor(term, constructor). :- mode convert_constructor(input, output). convert_constructor(Term, Result) :- (if some [Term1, Context] Term = term_functor(term_atom("{}"), [Term1], Context) then Term2 = Term1 else Term2 = Term ), parse_qualified_term(Term2, "constructor definition", ok(F, As)), convert_type_list(As, ArgTypes), Result = F - ArgTypes. %-----------------------------------------------------------------------------% % convert a "disjunction" (bunch of terms separated by ';'s) to a list :- pred disjunction_to_list(term, list(term)). :- mode disjunction_to_list(input, output). disjunction_to_list(Term, List) :- binop_term_to_list(";", Term, List). % convert a "conjunction" (bunch of terms separated by ','s) to a list :- pred conjunction_to_list(term, list(term)). :- mode conjunction_to_list(input, output). conjunction_to_list(Term, List) :- binop_term_to_list(",", Term, List). % convert a "sum" (bunch of terms separated by '+' operators) to a list :- pred sum_to_list(term, list(term)). :- mode sum_to_list(input, output). sum_to_list(Term, List) :- binop_term_to_list("+", Term, List). % general predicate to convert terms separated by any specified % operator into a list :- pred binop_term_to_list(string, term, list(term)). :- mode binop_term_to_list(input, input, output). binop_term_to_list(Op, Term, List) :- binop_term_to_list_2(Op, Term, [], List). :- pred binop_term_to_list_2(string, term, list(term), list(term)). :- mode binop_term_to_list_2(input, input, input, output). binop_term_to_list_2(Op, Term, List0, List) :- (if some [L, R, Context] Term = term_functor(term_atom(Op), [L, R], Context) then binop_term_to_list_2(Op, R, List0, List1), binop_term_to_list_2(Op, L, List1, List) else List = [Term|List0] ). %-----------------------------------------------------------------------------% % parse a `:- pred p(...)' declaration :- pred process_pred(varset, term, determinism, condition, maybe(item)). :- mode process_pred(input, input, input, input, output). process_pred(VarSet, PredType, Det, Cond, Result) :- parse_qualified_term(PredType, "`:- pred' declaration", R), process_pred_2(R, PredType, VarSet, Det, Cond, Result). :- pred process_pred_2(maybe_functor, term, varset, determinism, condition, maybe(item)). :- mode process_pred_2(input, input, input, input, input, output). process_pred_2(ok(F, As0), PredType, VarSet, Det, Cond, Result) :- (if some [As] convert_type_and_mode_list(As0, As) then Result = ok(pred(VarSet, F, As, Det, Cond)) else Result = error("syntax error in :- pred declaration", PredType) ). process_pred_2(error(M, T), _, _, _, _, error(M, T)). % parse a `:- mode p(...)' declaration :- pred process_mode(varset, term, determinism, condition, maybe(item)). :- mode process_mode(input, input, input, input, output). process_mode(VarSet, PredMode, Det, Cond, Result) :- parse_qualified_term(PredMode, "`:- mode' declaration", R), process_mode_2(R, PredMode, VarSet, Det, Cond, Result). :- pred process_mode_2(maybe_functor, term, varset, determinism, condition, maybe(item)). :- mode process_mode_2(input, input, input, input, input, output). process_mode_2(ok(F, As0), PredMode, VarSet, Det, Cond, Result) :- (if some [As] convert_mode_list(As0, As) then Result = ok(mode(VarSet, F, As, Det, Cond)) else Result = error("syntax error in predicate mode declaration", PredMode) ). process_mode_2(error(M, T), _, _, _, _, error(M, T)). /*** OBSOLETE % A rule declaration is just the same as a pred declaration, % except that it is for DCG rules, so there are two hidden arguments. :- pred process_rule(varset, term, condition, maybe(item)). :- mode process_rule(input, input, input, output). process_rule(VarSet, RuleType, Cond, Result) :- parse_qualified_term(RuleType, "`:- rule' declaration", R), process_rule_2(R, VarSet, Cond, Result). :- pred process_rule_2(maybe_functor, varset, condition, maybe(item)). :- mode process_rule_2(input, input, input, output). process_rule_2(ok(F, As), VarSet, Cond, ok(rule(VarSet, F, As, Cond))). process_rule_2(error(M, T), _, _, error(M, T)). ***/ /*** JUNK process_rule(VarSet, RuleType, Cond, Result) :- varset__new_var(VarSet, Var, VarSet1), RuleType = term_functor(F, RuleArgs, _), append(RuleArgs, [Var, Var], PredArgs), PredType = term_functor(F, PredArgs, _), process_pred(VarSet1, PredType, Cond, Result). ***/ %-----------------------------------------------------------------------------% % parse a `:- inst foo = ...' definition :- pred parse_inst_decl(varset, term, maybe(item)). :- mode parse_inst_decl(input, input, output). parse_inst_decl(VarSet, InstDefn, Result) :- (if some [H, B, Context] InstDefn = term_functor(term_atom("="), [H,B], Context) then get_condition(B, Body, Condition), convert_inst_defn(H, Body, R), process_inst_defn(R, VarSet, Condition, Result) else Result = error("`=' expected in `:- inst' definition", InstDefn) ). % we should check the condition for errs % (don't bother at the moment, since we ignore % conditions anyhow :-) :- pred convert_inst_defn(term, term, maybe(inst_defn)). :- mode convert_inst_defn(input, input, output). convert_inst_defn(Head, Body, Result) :- parse_qualified_term(Head, "inst definition", R), convert_inst_defn_2(R, Head, Body, Result). :- pred convert_inst_defn_2(maybe_functor, term, term, maybe(inst_defn)). :- mode convert_inst_defn_2(input, input, input, output). convert_inst_defn_2(error(M,T), _, _, error(M,T)). convert_inst_defn_2(ok(Name, Args), Head, Body, Result) :- % check that all the head args are variables (if some [Arg] ( member(Arg, Args), all [Var] Arg ~= term_variable(Var) ) then Result = error("Inst parameters must be variables", Arg) else % check that all the head arg variables are distinct if some [Arg2, OtherArgs] ( member(Arg2, Args, Arg2.OtherArgs), member(Arg2, OtherArgs) ) then Result = error("Repeated inst parameters in LHS of inst defn", Head) else % check that all the variables in the body occur in the head if some [Var2] ( term__contains_var(Body, Var2), not term__contains_var_list(Args, Var2) ) then Result = error("Free inst parameter in RHS of inst definition", Var2) else % should improve the error message here (if some [ConvertedBody] convert_inst(Body, ConvertedBody) then Result = ok(inst_defn(Name, Args, ConvertedBody)) else Result = error("syntax error in inst body", Body) ) ). :- pred convert_inst_list(list(term), list(inst)). :- mode convert_inst_list(input, output). convert_inst_list([], []). convert_inst_list([H0|T0], [H|T]) :- convert_inst(H0, H), convert_inst_list(T0, T). :- pred convert_inst(term, inst). :- mode convert_inst(input, output). convert_inst(term_variable(V), inst_var(V)). convert_inst(term_functor(Name, Args0, _), Result) :- (if Name = term_atom("free"), Args0 = [] then Result = free else if Name = term_atom("ground"), Args0 = [] then Result = ground else if some [Disj] (Name = term_atom("bound"), Args0 = [Disj]) then disjunction_to_list(Disj, List), convert_bound_inst_list(List, Functors), Result = bound(Functors) else convert_inst_list(Args0, Args), Result = user_defined_inst(Name, Args) ). :- pred convert_bound_inst_list(list(term), list(bound_inst)). :- mode convert_bound_inst_list(input, output). convert_bound_inst_list([], []). convert_bound_inst_list([H0|T0], [H|T]) :- convert_bound_inst(H0, H), convert_bound_inst_list(T0, T). :- pred convert_bound_inst(term, bound_inst). :- mode convert_bound_inst(input, output). convert_bound_inst(term_functor(Name, Args0, _), functor(Name, Args)) :- convert_inst_list(Args0, Args). :- pred process_inst_defn(maybe(inst_defn), varset, condition, maybe(item)). :- mode process_inst_defn(input, input, input, output). process_inst_defn(error(Error, Term), _, _, error(Error, Term)). process_inst_defn(ok(InstDefn), VarSet, Cond, ok(inst_defn(VarSet, InstDefn, Cond))). %-----------------------------------------------------------------------------% % parse a `:- mode foo :: ...' or `:- mode foo = ...' definition. :- pred parse_mode_decl(varset, term, maybe(item)). :- mode parse_mode_decl(input, input, output). parse_mode_decl(VarSet, ModeDefn, Result) :- (if some [H,B] mode_op(ModeDefn, H, B) then get_condition(B, Body, Condition), convert_mode_defn(H, Body, R), process_mode_defn(R, VarSet, Condition, Result) else parse_mode_decl_pred(VarSet, ModeDefn, Result) ). :- pred mode_op(term, term, term). :- mode mode_op(input, input, output). mode_op(term_functor(term_atom("::"),[H,B],_), H, B). mode_op(term_functor(term_atom("="),[H,B],_), H, B). :- pred convert_mode_defn(term, term, maybe(mode_defn)). :- mode convert_mode_defn(input, input, output). convert_mode_defn(Head, Body, Result) :- parse_qualified_term(Head, "mode definition", R), convert_mode_defn_2(R, Head, Body, Result). :- pred convert_mode_defn_2(maybe_functor, term, term, maybe(mode_defn)). :- mode convert_mode_defn_2(input, input, input, output). convert_mode_defn_2(error(M,T), _, _, error(M,T)). convert_mode_defn_2(ok(Name, Args), Head, Body, Result) :- % check that all the head args are variables (if some [Arg] ( member(Arg, Args), all [Var] Arg ~= term_variable(Var) ) then Result = error("Mode parameters must be variables", Arg) else % check that all the head arg variables are distinct if some [Arg2, OtherArgs] ( member(Arg2, Args, Arg2.OtherArgs), member(Arg2, OtherArgs) ) then Result = error("Repeated parameters in LHS of mode defn", Head) else % check that all the variables in the body occur in the head if some [Var2] ( term__contains_var(Body, Var2), not term__contains_var_list(Args, Var2) ) then Result = error("Free inst parameter in RHS of mode definition", Var2) else % should improve the error message here (if some [ConvertedBody] convert_mode(Body, ConvertedBody) then Result = ok(mode_defn(Name, Args, ConvertedBody)) else % catch-all error message - we should do % better than this Result = error("syntax error in mode definition body", Body) ) ). :- pred convert_type_and_mode_list(list(term), list(type_and_mode)). :- mode convert_type_and_mode_list(input, output). convert_type_and_mode_list([], []). convert_type_and_mode_list([H0|T0], [H|T]) :- convert_type_and_mode(H0, H), convert_type_and_mode_list(T0, T). :- pred convert_type_and_mode(term, type_and_mode). :- mode convert_type_and_mode(input, output). convert_type_and_mode(Term, Result) :- (if some [ModeTerm, TypeTerm, Context] Term = term_functor(term_atom("::"), [TypeTerm, ModeTerm], Context) then convert_type(TypeTerm, Type), convert_mode(ModeTerm, Mode), Result = type_and_mode(Type, Mode) else convert_type(Term, Type), Result = type_only(Type) ). :- pred convert_mode_list(list(term), list(mode)). :- mode convert_mode_list(input, output). convert_mode_list([], []). convert_mode_list([H0|T0], [H|T]) :- convert_mode(H0, H), convert_mode_list(T0, T). :- pred convert_mode(term, mode). :- mode convert_mode(input, output). convert_mode(Term, Mode) :- (if some [InstA, InstB, Context] Term = term_functor(term_atom("->"), [InstA, InstB], Context) then convert_inst(InstA, ConvertedInstA), convert_inst(InstB, ConvertedInstB), Mode = (ConvertedInstA -> ConvertedInstB) else parse_qualified_term(Term, "mode definition", R), R = ok(Name, Args), % should improve error reporting convert_inst_list(Args, ConvertedArgs), Mode = user_defined_mode(Name, ConvertedArgs) ). :- pred process_mode_defn(maybe(mode_defn), varset, condition, maybe(item)). :- mode process_mode_defn(input, input, input, output). process_mode_defn(error(Error, Term), _, _, error(Error, Term)). process_mode_defn(ok(ModeDefn), VarSet, Cond, ok(mode_defn(VarSet, ModeDefn, Cond))). %-----------------------------------------------------------------------------% % parse {import,use,export}_module declarations :- pred parse_import_module_decl(varset, term, maybe(item)). :- mode parse_import_module_decl(input, input, output). parse_import_module_decl(VarSet, ModuleSpec, Result) :- parse_module_spec_list(ModuleSpec, R), process_import(R, VarSet, Result). :- pred parse_use_module_decl(varset, term, maybe(item)). :- mode parse_use_module_decl(input, input, output). parse_use_module_decl(VarSet, ModuleSpec, Result) :- parse_module_spec_list(ModuleSpec, R), process_use(R, VarSet, Result). :- pred parse_export_module_decl(varset, term, maybe(item)). :- mode parse_export_module_decl(input, input, output). parse_export_module_decl(VarSet, ModuleSpec, Result) :- parse_module_spec_list(ModuleSpec, R), process_export(R, VarSet, Result). % parse {import,use,export}_sym declarations :- pred parse_export_sym_decl(varset, term, maybe(item)). :- mode parse_export_sym_decl(input, input, output). parse_export_sym_decl(VarSet, SymSpec, Result) :- parse_sym_spec_list(SymSpec, R), process_export(R, VarSet, Result). :- pred parse_import_sym_decl(varset, term, maybe(item)). :- mode parse_import_sym_decl(input, input, output). parse_import_sym_decl(VarSet, SymSpec, Result) :- parse_sym_spec_list(SymSpec, R), process_import(R, VarSet, Result). :- pred parse_use_sym_decl(varset, term, maybe(item)). :- mode parse_use_sym_decl(input, input, output). parse_use_sym_decl(VarSet, SymSpec, Result) :- parse_sym_spec_list(SymSpec, R), process_use(R, VarSet, Result). % parse {import,use,export}_pred declarations :- pred parse_import_pred_decl(varset, term, maybe(item)). :- mode parse_import_pred_decl(input, input, output). parse_import_pred_decl(VarSet, PredSpec, Result) :- parse_pred_spec_list(PredSpec, R), process_import(R, VarSet, Result). :- pred parse_use_pred_decl(varset, term, maybe(item)). :- mode parse_use_pred_decl(input, input, output). parse_use_pred_decl(VarSet, PredSpec, Result) :- parse_pred_spec_list(PredSpec, R), process_use(R, VarSet, Result). :- pred parse_export_pred_decl(varset, term, maybe(item)). :- mode parse_export_pred_decl(input, input, output). parse_export_pred_decl(VarSet, PredSpec, Result) :- parse_pred_spec_list(PredSpec, R), process_export(R, VarSet, Result). % parse {import,use,export}_cons declarations :- pred parse_import_cons_decl(varset, term, maybe(item)). :- mode parse_import_cons_decl(input, input, output). parse_import_cons_decl(VarSet, ConsSpec, Result) :- parse_cons_spec_list(ConsSpec, R), process_import(R, VarSet, Result). :- pred parse_use_cons_decl(varset, term, maybe(item)). :- mode parse_use_cons_decl(input, input, output). parse_use_cons_decl(VarSet, ConsSpec, Result) :- parse_cons_spec_list(ConsSpec, R), process_use(R, VarSet, Result). :- pred parse_export_cons_decl(varset, term, maybe(item)). :- mode parse_export_cons_decl(input, input, output). parse_export_cons_decl(VarSet, ConsSpec, Result) :- parse_cons_spec_list(ConsSpec, R), process_export(R, VarSet, Result). % parse {import,use,export}_type declarations :- pred parse_import_type_decl(varset, term, maybe(item)). :- mode parse_import_type_decl(input, input, output). parse_import_type_decl(VarSet, TypeSpec, Result) :- parse_type_spec_list(TypeSpec, R), process_import(R, VarSet, Result). :- pred parse_use_type_decl(varset, term, maybe(item)). :- mode parse_use_type_decl(input, input, output). parse_use_type_decl(VarSet, TypeSpec, Result) :- parse_type_spec_list(TypeSpec, R), process_use(R, VarSet, Result). :- pred parse_export_type_decl(varset, term, maybe(item)). :- mode parse_export_type_decl(input, input, output). parse_export_type_decl(VarSet, TypeSpec, Result) :- parse_type_spec_list(TypeSpec, R), process_export(R, VarSet, Result). % parse {import,use,export}_adt declarations :- pred parse_import_adt_decl(varset, term, maybe(item)). :- mode parse_import_adt_decl(input, input, output). parse_import_adt_decl(VarSet, ADT_Spec, Result) :- parse_adt_spec_list(ADT_Spec, R), process_import(R, VarSet, Result). :- pred parse_use_adt_decl(varset, term, maybe(item)). :- mode parse_use_adt_decl(input, input, output). parse_use_adt_decl(VarSet, ADT_Spec, Result) :- parse_adt_spec_list(ADT_Spec, R), process_use(R, VarSet, Result). :- pred parse_export_adt_decl(varset, term, maybe(item)). :- mode parse_export_adt_decl(input, input, output). parse_export_adt_decl(VarSet, ADT_Spec, Result) :- parse_adt_spec_list(ADT_Spec, R), process_export(R, VarSet, Result). % parse {import,use,export}_op declarations :- pred parse_import_op_decl(varset, term, maybe(item)). :- mode parse_import_op_decl(input, input, output). parse_import_op_decl(VarSet, OpSpec, Result) :- parse_op_spec_list(OpSpec, R), process_import(R, VarSet, Result). :- pred parse_use_op_decl(varset, term, maybe(item)). :- mode parse_use_op_decl(input, input, output). parse_use_op_decl(VarSet, OpSpec, Result) :- parse_op_spec_list(OpSpec, R), process_use(R, VarSet, Result). :- pred parse_export_op_decl(varset, term, maybe(item)). :- mode parse_export_op_decl(input, input, output). parse_export_op_decl(VarSet, OpSpec, Result) :- parse_op_spec_list(OpSpec, R), process_export(R, VarSet, Result). %-----------------------------------------------------------------------------% % Parse a comma-separated list (misleading described as % a "conjunction") of module specifiers. :- pred parse_module_spec_list(term, maybe(sym_list)). :- mode parse_module_spec_list(input, output). parse_module_spec_list(Term, Result) :- conjunction_to_list(Term, List), parse_module_spec_list_2(List, R), process_module_spec_list(R, Result). :- pred parse_module_spec_list_2(list(term), maybe(list(module_specifier))). :- mode parse_module_spec_list_2(input, output). parse_module_spec_list_2([], ok([])). parse_module_spec_list_2(X.Xs, Result) :- parse_module_specifier(X, X_Result), parse_module_spec_list_2(Xs, Xs_Result), combine_list_results(X_Result, Xs_Result, Result). :- pred process_module_spec_list(maybe(list(module_specifier)), maybe(sym_list)). :- mode process_module_spec_list(input, output). process_module_spec_list(ok(X), ok(module(X))). process_module_spec_list(error(M, T), error(M, T)). % Parse a comma-separated list (misleading described as % a "conjunction") of symbol specifiers. :- pred parse_sym_spec_list(term, maybe(sym_list)). :- mode parse_sym_spec_list(input, output). parse_sym_spec_list(Term, Result) :- conjunction_to_list(Term, List), parse_sym_spec_list_2(List, R), process_sym_spec_list(R, Result). :- pred parse_sym_spec_list_2(list(term), maybe(list(sym_specifier))). :- mode parse_sym_spec_list_2(input, output). parse_sym_spec_list_2([], ok([])). parse_sym_spec_list_2(X.Xs, Result) :- parse_symbol_specifier(X, X_Result), parse_sym_spec_list_2(Xs, Xs_Result), combine_list_results(X_Result, Xs_Result, Result). :- pred process_sym_spec_list(maybe(list(sym_specifier)), maybe(sym_list)). :- mode process_sym_spec_list(input, output). process_sym_spec_list(ok(X), ok(sym(X))). process_sym_spec_list(error(M, T), error(M, T)). % Parse a comma-separated list (misleading described as % a "conjunction") of predicate specifiers. :- pred parse_pred_spec_list(term, maybe(sym_list)). :- mode parse_pred_spec_list(input, output). parse_pred_spec_list(Term, Result) :- conjunction_to_list(Term, List), parse_pred_spec_list_2(List, R), process_pred_spec_list(R, Result). :- pred parse_pred_spec_list_2(list(term), maybe(list(pred_specifier))). :- mode parse_pred_spec_list_2(input, output). parse_pred_spec_list_2([], ok([])). parse_pred_spec_list_2(X.Xs, Result) :- parse_predicate_specifier(X, X_Result), parse_pred_spec_list_2(Xs, Xs_Result), combine_list_results(X_Result, Xs_Result, Result). :- pred process_pred_spec_list(maybe(list(pred_specifier)), maybe(sym_list)). :- mode process_pred_spec_list(input, output). process_pred_spec_list(ok(X), ok(pred(X))). process_pred_spec_list(error(M, T), error(M, T)). % Parse a comma-separated list (misleading described as % a "conjunction") of constructor specifiers. :- pred parse_cons_spec_list(term, maybe(sym_list)). :- mode parse_cons_spec_list(input, output). parse_cons_spec_list(Term, Result) :- conjunction_to_list(Term, List), parse_cons_spec_list_2(List, R), process_cons_spec_list(R, Result). :- pred parse_cons_spec_list_2(list(term), maybe(list(cons_specifier))). :- mode parse_cons_spec_list_2(input, output). parse_cons_spec_list_2([], ok([])). parse_cons_spec_list_2(X.Xs, Result) :- parse_constructor_specifier(X, X_Result), parse_cons_spec_list_2(Xs, Xs_Result), combine_list_results(X_Result, Xs_Result, Result). :- pred process_cons_spec_list(maybe(list(cons_specifier)), maybe(sym_list)). :- mode process_cons_spec_list(input, output). process_cons_spec_list(ok(X), ok(cons(X))). process_cons_spec_list(error(M, T), error(M, T)). % Parse a comma-separated list (misleading described as % a "conjunction") of type specifiers. :- pred parse_type_spec_list(term, maybe(sym_list)). :- mode parse_type_spec_list(input, output). parse_type_spec_list(Term, Result) :- conjunction_to_list(Term, List), parse_type_spec_list_2(List, R), process_type_spec_list(R, Result). :- pred parse_type_spec_list_2(list(term), maybe(list(sym_name_specifier))). :- mode parse_type_spec_list_2(input, output). parse_type_spec_list_2([], ok([])). parse_type_spec_list_2(X.Xs, Result) :- parse_type_specifier(X, X_Result), parse_type_spec_list_2(Xs, Xs_Result), combine_list_results(X_Result, Xs_Result, Result). :- pred process_type_spec_list(maybe(list(sym_name_specifier)), maybe(sym_list)). :- mode process_type_spec_list(input, output). process_type_spec_list(ok(X), ok(type(X))). process_type_spec_list(error(M, T), error(M, T)). % Parse a comma-separated list (misleading described as % a "conjunction") of adt specifiers. :- pred parse_adt_spec_list(term, maybe(sym_list)). :- mode parse_adt_spec_list(input, output). parse_adt_spec_list(Term, Result) :- conjunction_to_list(Term, List), parse_adt_spec_list_2(List, R), process_adt_spec_list(R, Result). :- pred parse_adt_spec_list_2(list(term), maybe(list(sym_name_specifier))). :- mode parse_adt_spec_list_2(input, output). parse_adt_spec_list_2([], ok([])). parse_adt_spec_list_2(X.Xs, Result) :- parse_adt_specifier(X, X_Result), parse_adt_spec_list_2(Xs, Xs_Result), combine_list_results(X_Result, Xs_Result, Result). :- pred process_adt_spec_list(maybe(list(sym_name_specifier)), maybe(sym_list)). :- mode process_adt_spec_list(input, output). process_adt_spec_list(ok(X), ok(adt(X))). process_adt_spec_list(error(M, T), error(M, T)). % Parse a comma-separated list (misleading described as % a "conjunction") of operator specifiers. :- pred parse_op_spec_list(term, maybe(sym_list)). :- mode parse_op_spec_list(input, output). parse_op_spec_list(Term, Result) :- conjunction_to_list(Term, List), parse_op_spec_list_2(List, R), process_op_spec_list(R, Result). :- pred parse_op_spec_list_2(list(term), maybe(list(sym_name_specifier))). :- mode parse_op_spec_list_2(input, output). parse_op_spec_list_2([], ok([])). parse_op_spec_list_2(X.Xs, Result) :- parse_op_specifier(X, X_Result), parse_op_spec_list_2(Xs, Xs_Result), combine_list_results(X_Result, Xs_Result, Result). :- pred process_op_spec_list(maybe(list(op_specifier)), maybe(sym_list)). :- mode process_op_spec_list(input, output). process_op_spec_list(ok(X), ok(op(X))). process_op_spec_list(error(M, T), error(M, T)). %-----------------------------------------------------------------------------% % If a list of things contains multiple errors, then we only % report the first one. :- pred combine_list_results(maybe(T), maybe(list(T)), maybe(list(T))). :- mode combine_list_results(input, input, output). combine_list_results(error(Msg, Term), _, error(Msg, Term)). combine_list_results(ok(_), error(Msg, Term), error(Msg, Term)). combine_list_results(ok(X), ok(Xs), ok([X|Xs])). %-----------------------------------------------------------------------------% % % A symbol specifier is one of % % SymbolNameSpecifier % Matches any symbol matched by the SymbolNameSpecifier. % TypedConstructorSpecifier % Matches any constructors matched by the % TypedConstructorSpecifier. % cons(ConstructorSpecifier) % Matches only constructors. % pred(PredSpecifier) % Matches only predicates, ie. constructors of type % `pred'. % adt(SymbolNameSpecifier) % Matches only type names. % type(SymbolNameSpecifier) % Matches type names matched by the SymbolNameSpecifier, % and also matches any constructors for the matched type % names. % op(SymbolNameSpecifier) % Matches only operators. % module(ModuleSpecifier) % Matches all symbols in the specified module. :- pred parse_symbol_specifier(term, maybe(sym_specifier)). parse_symbol_specifier(Term, Result) :- (if some [ConsSpecTerm, Context1] Term = term_functor(term_atom("cons"), [ConsSpecTerm], Context1) then parse_constructor_specifier(ConsSpecTerm, ConsSpecResult), process_cons_symbol_specifier(ConsSpecResult, Result) else if some [PredSpecTerm, Context2] Term = term_functor(term_atom("pred"), [PredSpecTerm], Context2) then parse_predicate_specifier(PredSpecTerm, PredSpecResult), process_pred_symbol_specifier(PredSpecResult, Result) else if some [TypeSpecTerm, Context3] Term = term_functor(term_atom("type"), [TypeSpecTerm], Context3) then parse_type_specifier(TypeSpecTerm, TypeSpecResult), process_type_symbol_specifier(TypeSpecResult, Result) else if some [AdtSpecTerm, Context4] Term = term_functor(term_atom("adt"), [AdtSpecTerm], Context4) then parse_adt_specifier(AdtSpecTerm, AdtSpecResult), process_adt_symbol_specifier(AdtSpecResult, Result) else if some [OpSpecTerm, Context5] Term = term_functor(term_atom("op"), [OpSpecTerm], Context5) then parse_op_specifier(OpSpecTerm, OpSpecResult), process_op_symbol_specifier(OpSpecResult, Result) else if some [ModuleSpecTerm, Context6] Term = term_functor(term_atom("module"), [ModuleSpecTerm], Context6) then parse_module_specifier(ModuleSpecTerm, ModuleSpecResult), process_module_symbol_specifier(ModuleSpecResult, Result) else parse_constructor_specifier(Term, TermResult), process_any_symbol_specifier(TermResult, Result) ). % Once we've parsed the appropriate type of symbol specifier, we % need to convert it to a sym_specifier, propagating errors upwards. :- pred process_module_symbol_specifier(maybe(module_specifier), maybe(sym_specifier)). :- mode process_module_symbol_specifier(input, output). process_module_symbol_specifier(ok(OpSpec), ok(module(OpSpec))). process_module_symbol_specifier(error(Msg, Term), error(Msg, Term)). :- pred process_any_symbol_specifier(maybe(cons_specifier), maybe(sym_specifier)). :- mode process_any_symbol_specifier(input, output). process_any_symbol_specifier(error(Msg, Term), error(Msg, Term)). process_any_symbol_specifier(ok(sym(SymSpec)), ok(sym(SymSpec))). process_any_symbol_specifier(ok(typed(ConsSpec)), ok(typed_sym(ConsSpec))). :- pred process_pred_symbol_specifier(maybe(pred_specifier), maybe(sym_specifier)). :- mode process_pred_symbol_specifier(input, output). process_pred_symbol_specifier(error(Msg, Term), error(Msg, Term)). process_pred_symbol_specifier(ok(PredSpec), ok(pred(PredSpec))). :- pred process_cons_symbol_specifier(maybe(cons_specifier), maybe(sym_specifier)). :- mode process_cons_symbol_specifier(input, output). process_cons_symbol_specifier(error(Msg, Term), error(Msg, Term)). process_cons_symbol_specifier(ok(ConsSpec), ok(cons(ConsSpec))). :- pred process_type_symbol_specifier(maybe(sym_name_specifier), maybe(sym_specifier)). :- mode process_type_symbol_specifier(input, output). process_type_symbol_specifier(ok(SymSpec), ok(type(SymSpec))). process_type_symbol_specifier(error(Msg, Term), error(Msg, Term)). :- pred process_adt_symbol_specifier(maybe(sym_name_specifier), maybe(sym_specifier)). :- mode process_adt_symbol_specifier(input, output). process_adt_symbol_specifier(ok(SymSpec), ok(adt(SymSpec))). process_adt_symbol_specifier(error(Msg, Term), error(Msg, Term)). :- pred process_op_symbol_specifier(maybe(op_specifier), maybe(sym_specifier)). :- mode process_op_symbol_specifier(input, output). process_op_symbol_specifier(ok(OpSpec), ok(op(OpSpec))). process_op_symbol_specifier(error(Msg, Term), error(Msg, Term)). %-----------------------------------------------------------------------------% % A ModuleSpecifier is just an identifier. :- pred parse_module_specifier(term, maybe(module_specifier)). :- mode parse_module_specifier(input, output). parse_module_specifier(Term, Result) :- (if some [ModuleName, Context] Term = term_functor(term_atom(ModuleName), [], Context) then Result = ok(ModuleName) else Result = error("module specifier should be an identifier", Term) ). %-----------------------------------------------------------------------------% % A ConstructorSpecifier is one of % SymbolNameSpecifier % TypedConstructorSpecifier % % A TypedConstructorSpecifier is one of % SymbolNameSpecifier::Type % Matches only constructors with the specified result % type. % SymbolName(ArgType1, ..., ArgTypeN) % Matches only constructors with the specified argument % types. % SymbolName(ArgType1, ..., ArgTypeN)::Type % Matches only constructors with the specified argument % and result types. :- pred parse_constructor_specifier(term, maybe(cons_specifier)). :- mode parse_constructor_specifier(input, output). parse_constructor_specifier(Term, Result) :- (if some [NameArgsTerm, TypeTerm, Context] Term = term_functor(term_atom("::"), [NameArgsTerm, TypeTerm], Context) then parse_arg_types_specifier(NameArgsTerm, NameArgsResult), parse_type(TypeTerm, TypeResult), process_typed_constructor_specifier(NameArgsResult, TypeResult, Result) else parse_arg_types_specifier(Term, TermResult), process_untyped_constructor_specifier(TermResult, Result) ). %-----------------------------------------------------------------------------% % A PredicateSpecifier is one of % SymbolName(ArgType1, ..., ArgTypeN) % Matches only predicates with the specified argument % types. % SymbolNameSpecifier :- pred parse_predicate_specifier(term, maybe(pred_specifier)). :- mode parse_predicate_specifier(input, output). parse_predicate_specifier(Term, Result) :- (if some [X, Y, Context] Term = term_functor(term_atom("/"), [X,Y], Context) then parse_symbol_name_specifier(Term, TermResult), process_arity_predicate_specifier(TermResult, Result) else parse_qualified_term(Term, "predicate specifier", TermResult), process_typed_predicate_specifier(TermResult, Result) ). :- pred process_typed_predicate_specifier(maybe_functor, maybe(pred_specifier)). :- mode process_typed_predicate_specifier(input, output). process_typed_predicate_specifier(ok(Name, Args), ok(Result)) :- (if Args = [] then Result = sym(name(Name)) else Result = name_args(Name, Args) ). process_typed_predicate_specifier(error(Msg, Term), error(Msg, Term)). :- pred process_arity_predicate_specifier(maybe(sym_name_specifier), maybe(pred_specifier)). :- mode process_arity_predicate_specifier(input, output). process_arity_predicate_specifier(ok(Result), ok(sym(Result))). process_arity_predicate_specifier(error(Msg, Term), error(Msg, Term)). %-----------------------------------------------------------------------------% % Parsing the name & argument types of a constructor specifier is % exactly the same as parsing a predicate specifier... :- pred parse_arg_types_specifier(term, maybe(pred_specifier)). :- mode parse_arg_types_specifier(input, output). parse_arg_types_specifier(Term, Result) :- (if some [X, Y, Context] Term = term_functor(term_atom("/"), [X,Y], Context) then parse_symbol_name_specifier(Term, TermResult), process_arity_predicate_specifier(TermResult, Result) else parse_qualified_term(Term, "constructor specifier", TermResult), process_typed_predicate_specifier(TermResult, Result) ). % ... but we have to convert the result back into the appropriate % format. :- pred process_typed_constructor_specifier(maybe(pred_specifier), maybe(type), maybe(cons_specifier)). :- mode process_typed_constructor_specifier(input, input, output). process_typed_constructor_specifier(error(Msg, Term), _, error(Msg, Term)). process_typed_constructor_specifier(_, error(Msg, Term), error(Msg, Term)). process_typed_constructor_specifier(ok(NameArgs), ok(ResType), ok(Result)) :- process_typed_cons_spec_2(NameArgs, ResType, Result). :- pred process_typed_cons_spec_2(pred_specifier, type, cons_specifier). :- mode process_typed_cons_spec_2(input, input, output). process_typed_cons_spec_2(sym(Name), Res, typed(name_res(Name, Res))). process_typed_cons_spec_2(name_args(Name, Args), Res, typed(name_args_res(Name, Args, Res))). :- pred process_untyped_constructor_specifier(maybe(pred_specifier), maybe(cons_specifier)). :- mode process_untyped_constructor_specifier(input, output). process_untyped_constructor_specifier(error(Msg, Term), error(Msg, Term)). process_untyped_constructor_specifier(ok(NameArgs), ok(Result)) :- process_untyped_cons_spec_2(NameArgs, Result). :- pred process_untyped_cons_spec_2(pred_specifier, cons_specifier). :- mode process_untyped_cons_spec_2(input, output). process_untyped_cons_spec_2(sym(Name), sym(Name)). process_untyped_cons_spec_2(name_args(Name, Args), typed(name_args(Name, Args))). %-----------------------------------------------------------------------------% % A SymbolNameSpecifier is one of % SymbolName % SymbolName/Arity % Matches only symbols of the specified arity. % :- pred parse_symbol_name_specifier(term, maybe(sym_name_specifier)). :- mode parse_symbol_name_specifier(input, output). parse_symbol_name_specifier(Term, Result) :- (if some [NameTerm, ArityTerm, Context] Term = term_functor(term_atom("/"), [NameTerm, ArityTerm], Context) then (if some [Arity, Context2] ArityTerm = term_functor(term_integer(Arity), [], Context2) then (if Arity >= 0 then parse_symbol_name(NameTerm, NameResult), process_name_arity_specifier(NameResult, Arity, Result) else Result = error("Arity in symbol name specifier must be a non-negative integer", Term) ) else Result = error("Arity in symbol name specifier must be an integer", Term) ) else parse_symbol_name(Term, SymbolNameResult), process_name_specifier(SymbolNameResult, Result) ). :- pred process_name_arity_specifier(maybe(sym_name), int, maybe(sym_name_specifier)). :- mode process_name_arity_specifier(input, input, output). process_name_arity_specifier(ok(Name), Arity, ok(name_arity(Name, Arity))). process_name_arity_specifier(error(Error, Term), _, error(Error, Term)). :- pred process_name_specifier(maybe(sym_name), maybe(sym_name_specifier)). :- mode process_name_specifier(input, output). process_name_specifier(ok(Name), ok(name(Name))). process_name_specifier(error(Error, Term), error(Error, Term)). %-----------------------------------------------------------------------------% % A QualifiedTerm is one of % Name(Args) % Module:Name(Args) % (or if Args is empty, one of % Name % Module:Name) :- pred parse_qualified_term(term, string, maybe_functor). :- mode parse_qualified_term(input, input, output). parse_qualified_term(Term, Msg, Result) :- (if some [ModuleTerm, NameArgsTerm, Context] Term = term_functor(term_atom(":"), [ModuleTerm, NameArgsTerm], Context) then (if some [Name, Args, Context2] NameArgsTerm = term_functor(term_atom(Name), Args, Context2) then (if some [Module, Context3] ModuleTerm = term_functor(term_atom(Module), [], Context3) then Result = ok(qualified(Module, Name), Args) else Result = error("module name identifier expected before ':' in qualified symbol name", Term) ) else Result = error("identifier expected after ':' in qualified symbol name", Term) ) else (if some [Name2, Args2, Context4] Term = term_functor(term_atom(Name2), Args2, Context4) then Result = ok(unqualified(Name2), Args2) else string__append("atom expected in ", Msg, ErrorMsg), Result = error(ErrorMsg, Term) ) ). %-----------------------------------------------------------------------------% % A SymbolName is one of % Name % Matches symbols with the specified name in the % current namespace. % Module:Name % Matches symbols with the specified name exported % by the specified module. :- pred parse_symbol_name(term, maybe(sym_name)). :- mode parse_symbol_name(input, output). parse_symbol_name(Term, Result) :- (if some [ModuleTerm, NameTerm, Context] Term = term_functor(term_atom(":"), [ModuleTerm, NameTerm], Context) then (if some [Name, Context1] NameTerm = term_functor(term_atom(Name), [], Context1) then (if some [Module, Context2] ModuleTerm = term_functor(term_atom(Module), [], Context2) then Result = ok(qualified(Module, Name)) else Result = error("module name identifier expected before ':' in qualified symbol name", Term) ) else Result = error("identifier expected after ':' in qualified symbol name", Term) ) else (if some [Name2, Context3] Term = term_functor(term_atom(Name2), [], Context3) then Result = ok(unqualified(Name2)) else Result = error("symbol name specifier expected", Term) ) ). %-----------------------------------------------------------------------------% % convert a module definition to a program item, % propagating errors upwards :- pred process_import(maybe(module_defn), varset, maybe(item)). :- mode process_import(input, input, output). process_import(ok(X), VarSet, ok(module_defn(VarSet, import(X)))). process_import(error(Msg, Term), _, error(Msg, Term)). :- pred process_use(maybe(module_defn), varset, maybe(item)). :- mode process_use(input, input, output). process_use(ok(X), VarSet, ok(module_defn(VarSet, use(X)))). process_use(error(Msg, Term), _, error(Msg, Term)). :- pred process_export(maybe(module_defn), varset, maybe(item)). :- mode process_export(input, input, output). process_export(ok(X), VarSet, ok(module_defn(VarSet, export(X)))). process_export(error(Msg, Term), _, error(Msg, Term)). %-----------------------------------------------------------------------------% % A TypeSpecifier is just a symbol name specifier. :- pred parse_type_specifier(term, maybe(sym_name_specifier)). :- mode parse_type_specifier(input, output). parse_type_specifier(Term, Result) :- parse_symbol_name_specifier(Term, Result). % An ADT_Specifier is just a symbol name specifier. :- pred parse_adt_specifier(term, maybe(sym_name_specifier)). :- mode parse_adt_specifier(input, output). parse_adt_specifier(Term, Result) :- parse_symbol_name_specifier(Term, Result). %-----------------------------------------------------------------------------% % For the moment, an OpSpecifier is just a symbol name specifier. % XXX We should allow specifying the fixity of an operator :- pred parse_op_specifier(term, maybe(op_specifier)). :- mode parse_op_specifier(input, output). parse_op_specifier(Term, Result) :- parse_symbol_name_specifier(Term, R), process_op_specifier(R, Result). :- pred process_op_specifier(maybe(sym_name_specifier), maybe(op_specifier)). :- mode process_op_specifier(input, output). process_op_specifier(ok(X), ok(sym(X))). process_op_specifier(error(M,T), error(M,T)). %-----------------------------------------------------------------------------% % types are represented just as ordinary terms :- pred parse_type(term, maybe(type)). :- mode parse_type(input, output). parse_type(T, ok(T)). :- pred convert_type_list(list(term), list(type)). :- mode convert_type_list(input, output). convert_type_list([], []). convert_type_list([H0|T0], [H|T]) :- convert_type(H0, H), convert_type_list(T0, T). :- pred convert_type(term, type). :- mode convert_type(input, output). convert_type(T, T). %-----------------------------------------------------------------------------%