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91737ed565c426f26b916fa080def66162693e15
mercury/compiler/prog_io.m
Fergus Henderson 91737ed565 Added code to parse mode declarations.
1993-12-01 11:55:55 +00:00

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%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%
:- module prog_io.
:- import_module string, list, varset, term, io.
% This module defines a data structure for representing Mercury
% programs.
%
% In some ways the representation of programs 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.
%
% Some of this code is a nightmare 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???
%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%
:- interface.
%-----------------------------------------------------------------------------%
:- type int == integer. % XXX put this somewhere central
%-----------------------------------------------------------------------------%
% This is how programs (and parse errors) are represented.
:- type maybe_program ---> ok(message_list, program)
; error(message_list).
:- type message_list == list(pair(string, term)).
% the error/warning message, and the
% term to which it relates
:- type program ---> module(module_name, list(item)).
:- 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),
condition)
% VarNames, PredName, ArgTypes, Cond
; rule(varset, sym_name, list(type), condition)
% VarNames, PredName, ArgTypes, Cond
; mode(varset, sym_name, list(mode), condition)
% VarNames, PredName, ArgModes, Cond
; unimplemented % XXX
; error.
:- type type_and_mode ---> type_only(type)
; type_and_mode(type, mode).
%-----------------------------------------------------------------------------%
% 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).
:- 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).
% XXX constructor should be pair(sym_name, list(type)) not term.
:- type constructor == term.
% XXX type parameters should 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 inst parameters should be variables not terms.
:- type inst_param == term.
:- type (inst) ---> free
; bound(list(bound_inst))
; ground
; inst_var(var)
; 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, maybe_program, io__state, io__state).
:- mode prog_io__read_program(input, output, di, uo).
% read_program(FileName, Result)
% - reads and parses file 'FileName'. Result is either
% ok(Warnings,Program) or error(Messages) where Warnings
% is a list of warning messages, Program is the parse tree,
% and Messages is a list of warning/error messages.
%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%
:- 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_constructor == maybe2(sym_name, list(type)).
% 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_program(FileName, Result) -->
io__op(1199, fx, "rule"),
io__op(1179, xfy, "--->"), % XXX should be automatic
io__see(FileName, R),
(if { R = ok } then
read_program_3(RevMessages, RevItems0, Error),
{
get_end_module(RevItems0, RevItems, EndModule),
reverse(RevMessages, Messages),
reverse(RevItems, Items),
check_begin_module(Messages, Items, Error, EndModule,
Result)
},
io__seen
else
{ io__progname(Progname),
string__append(Progname, ": can't open file '", Message1),
string__append(Message1, FileName, Message2),
string__append(Message2, "'.\n", Message),
Term = term_functor(term_atom("<end of file>"), [])
}
).
%-----------------------------------------------------------------------------%
% extract the final `:- end_module' declaration if any
:- type module_end ---> no ; yes(module_name).
:- pred get_end_module(message_list, message_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))
| RevItems1]
then
RevItems = RevItems1,
EndModule = yes(ModuleName)
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, list(item), yes_or_no,
module_end, maybe_program).
:- mode check_begin_module(input, input, input, input, output).
check_begin_module(Messages0, Items0, Error, EndModule, Result) :-
% check that the first item is a `:- module ModuleName'
% declaration
(if some [VarSet, ModuleName1, Items1]
Items0 = [module_defn(VarSet, module(ModuleName1))
| Items1]
then
% check that the end module declaration (if any)
% matches the begin module declaration
(if some [ModuleName2] (
EndModule = yes(ModuleName2),
ModuleName1 \= ModuleName2
)
then
ThisError = error(
"`:- end_module' declaration doesn't match `:- module' declaration",
term_functor(term_atom("<end of file>"), []) ),
append([ThisError], Messages0, Messages),
Program = error(Messages)
else
(if Error = yes then
Program = error(Messages0)
else
Program = ok(Messages0, module(ModuleName1,Items1))
)
)
else
ThisError = error("module should start with a ':- module' declaration",
term_functor(term_atom("<start of file>"), []) ),
Program = error([ThisError | Messages])
).
%-----------------------------------------------------------------------------%
% 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.
:- type yes_or_no ---> yes ; no.
:- pred read_program_3(message_list, program, yes_or_no, io__state, io__state).
:- mode read_program_3(output, output, output, di, uo).
read_program_3(Messages, Items, Error) -->
io__read_term(MaybeTerm),
read_program_4(MaybeTerm, [], [], no, Messages, Items, Error).
:- pred read_program_4(read_term, message_list, program, yes_or_no,
message_list, program, yes_or_no,
io__state,io__state).
:- mode read_program_4(input, input, input, input,
output, output, output, di, uo).
read_program_4(eof, Msgs, Items, Error, Msgs, Items, Error) --> [].
read_program_4(error(ErrorMsg), Msgs0, Items, _, Msgs, Items, yes) -->
{
Error = error(Msg, term_functor(term_atom(""), [])),
Msgs = [Error | Msgs]
}.
read_program_4(term(VarSet, Term), Msgs0, Items0,
Error0, Msgs, Items, Error) -->
{
parse_item(VarSet, Term, MaybeItem),
process_item(MaybeItem, Msgs0, Items0, Error0,
Msgs1, Items1, Error1)
},
io__read_term(MaybeTerm),
read_program_4(MaybeTerm, Messages1, Items1, Error1,
Msgs, Items, Error).
:- pred process_item(maybe(item), message_list, program, yes_or_no,
message_list, program, yes_or_no).
:- mode process_item(input, input, input, input,
output, output, output).
process_item(ok(Item), Msgs, Items0, Error, Msgs, [Item|Items0], Error).
process_item(error(M,T), Msgs0, Items, _, Msgs, Items0, yes) :-
add_error(M, T, Msgs0, Msgs).
:- pred parse_item(varset, term, maybe(item)).
:- mode parse_item(input, input, output).
parse_item(VarSet, Term, Result) :-
(if some [Decl]
Term = term_functor(term_atom(":-"), [Decl])
then
parse_decl(VarSet, Decl, Result)
else
% OK, it's not a declaration. Is it a fact, or a rule?
(if some [H,B]
Term = term_functor(term_atom(":-"), [H,B])
then % it's a fact
Head = H,
Body = B
else % it's a rule
Head = Term,
Body = term_functor(term_atom("true"), [])
),
parse_goal(Body, Body2),
parse_qualified_term(Head, "clause head", Result),
process_clause(Result, VarSet, Body2, Msgs0, Error0,
Item, Msgs1, Error)
).
:- pred process_clause(maybe_functor, varset, term, maybe(item)).
:- mode process_clause(input, 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(yes_or_no, yes_or_no, yes_or_no).
:- mode join_error(input, input, output).
join_error(yes, _, yes).
join_error(no, Error, Error).
%-----------------------------------------------------------------------------%
% parse a goal
:- 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(","),[A0,B0]), (A,B)) :-
parse_goal(A0, 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("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("all"),[Vars0,A0]),all(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]
A0 = term_functor(term_atom("some"), [Vars0,A1])
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]
F = term_functor(term_atom(Atom), As)
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))).
% XXX
process_decl(VarSet, "module", [_ModuleName], ok(unimplemented)).
process_decl(VarSet, "end_module", [_ModuleName], ok(unimplemented)).
:- 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
parse_type_decl_2(R, VarSet, Cond, Result)
else
Result = error("Invalid type declaration (need =, == or --->)", TypeDecl)
).
:- 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))).
% XXX 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 "pred" 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),
process_pred(VarSet, Body, 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 "pred" 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),
process_mode(VarSet, Body, Condition, R).
%-----------------------------------------------------------------------------%
% 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]
B = term_functor(term_atom("where"), [Body1, Condition1])
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)
).
%-----------------------------------------------------------------------------%
% 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
:- pred convert_constructor(term, constructor).
:- mode convert_constructor(input, output).
convert_constructor(term_functor(Functor,Args), term_functor(Functor,Args)).
%-----------------------------------------------------------------------------%
% 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]
Term = term_functor(term_atom(Op), [L, R])
then
binop_term_to_list_2(Op, L, List0, List1),
binop_term_to_list_2(Op, R, List1, List)
else
List = [Term|List0]
).
%-----------------------------------------------------------------------------%
% parse a `:- pred p(...)' declaration
:- pred process_pred(varset, term, condition, maybe(item)).
:- mode process_pred(input, input, input, output).
process_pred(VarSet, PredType, Cond, Result) :-
parse_qualified_term(PredType, "`:- pred' declaration", R),
process_pred_2(R, PredType, VarSet, Cond, Result).
:- pred process_pred_2(maybe_functor, term, varset, condition, maybe(item)).
:- mode process_pred_2(input, input, input, input, output).
process_pred_2(ok(F, As0), PredType, VarSet, Cond, Result) :-
(if some [As]
convert_type_and_mode_list(As0, As)
then
Result = ok(pred(VarSet, F, As, 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, condition, maybe(item)).
:- mode process_mode(input, input, input, output).
process_mode(VarSet, PredMode, Cond, Result) :-
parse_qualified_term(PredMode, "`:- mode' declaration", R),
process_mode_2(R, PredMode, VarSet, Cond, Result).
:- pred process_mode_2(maybe_functor, term, varset, condition, maybe(item)).
:- mode process_mode_2(input, input, input, input, output).
process_mode_2(ok(F, As0), PredMode, VarSet, Cond, Result) :-
(if some [As]
convert_mode_list(As0, As)
then
Result = ok(mode(VarSet, F, As, 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]
InstDefn = term_functor(term_atom("="),[H,B])
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)
).
% XXX 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
% XXX catch-all error message
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]
Term = term_functor(term_atom("::"), [ModeTerm, TypeTerm])
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]
Term = term_functor(term_atom("->"), [InstA, InstB])
then
convert_inst(InstA, ConvertedInstA),
convert_inst(InstB, ConvertedInstB),
Mode = (ConvertedInstA -> ConvertedInstB)
else
parse_qualified_term(Term, "mode definition", R),
R = ok(Name, Args), % XXX 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]
Term = term_functor(term_atom("cons"), [ConsSpecTerm])
then
parse_constructor_specifier(ConsSpecTerm, ConsSpecResult),
process_cons_symbol_specifier(ConsSpecResult, Result)
else if some [PredSpecTerm]
Term = term_functor(term_atom("pred"), [PredSpecTerm])
then
parse_predicate_specifier(PredSpecTerm, PredSpecResult),
process_pred_symbol_specifier(PredSpecResult, Result)
else if some [TypeSpecTerm]
Term = term_functor(term_atom("type"), [TypeSpecTerm])
then
parse_type_specifier(TypeSpecTerm, TypeSpecResult),
process_type_symbol_specifier(TypeSpecResult, Result)
else if some [AdtSpecTerm]
Term = term_functor(term_atom("adt"), [AdtSpecTerm])
then
parse_adt_specifier(AdtSpecTerm, AdtSpecResult),
process_adt_symbol_specifier(AdtSpecResult, Result)
else if some [OpSpecTerm]
Term = term_functor(term_atom("op"), [OpSpecTerm])
then
parse_op_specifier(OpSpecTerm, OpSpecResult),
process_op_symbol_specifier(OpSpecResult, Result)
else if some [ModuleSpecTerm]
Term = term_functor(term_atom("module"), [ModuleSpecTerm])
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]
Term = term_functor(term_atom(ModuleName), [])
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]
Term = term_functor(term_atom("::"), [NameArgsTerm, TypeTerm])
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] Term = term_functor(term_atom("/"), [X,Y]) 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] Term = term_functor(term_atom("/"), [X,Y]) 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]
Term = term_functor(term_atom("/"), [NameTerm, ArityTerm])
then
(if some [Arity]
ArityTerm = term_functor(term_integer(Arity),[])
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]
Term = term_functor(term_atom(":"), [ModuleTerm, NameArgsTerm])
then
(if some [Name, Args]
NameArgsTerm = term_functor(term_atom(Name),Args)
then
(if some [Module]
ModuleTerm = term_functor(term_atom(Module),[])
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]
Term = term_functor(term_atom(Name2), Args2)
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]
Term = term_functor(term_atom(":"), [ModuleTerm, NameTerm])
then
(if some [Name]
NameTerm = term_functor(term_atom(Name),[])
then
(if some [Module]
ModuleTerm = term_functor(term_atom(Module),[])
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]
Term = term_functor(term_atom(Name2),[])
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(term, type).
:- mode convert_type(input, output).
convert_type(T, T).
%-----------------------------------------------------------------------------%
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