Files
mercury/compiler/polymorphism.m
Fergus Henderson 865beeb3ca Various minor bugfixes.
Makefile.common:
	Various minor bugfixes.

Makefile.mercury:
	Add rules for creating assembler (.s) files.

term.nl, *.nl:
	Replace term__context_init/1 with term__context_init/0.
	The first argument was always zero anyway.

io.nl:
	Change the interface to io__read_char and io__read_line so that
	they return a better error indicator.
	Add a new predicate io__putback_char.

polymorphism.nl:
	Don't abort if a predicate doesn't have any modes.

options.nl:
	Let's try turning polymorphism on again.  It seems to work this time.

string.nl, string.nu.nl:
	Add string__to_float.
	Move implementation of string__to_int from string.nl to string.nu.nl.
1995-01-23 17:07:17 +00:00

626 lines
23 KiB
Mathematica

%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%
% file: polymorphism.nl
% main author: fjh
% This module is a pass over the HLDS.
% It does a syntactic transformation to implement polymorphic unifications
% using higher-order predicates. Every polymorphic predicate is transformed
% so that it takes one additional argument for every type variable in the
% predicate's type declaration. The argument is a higher-order predicate
% argument which is (the address of) the unification predicate for that type.
% Every polymorphic unification is replaced by a call to one of these
% predicates.
%
% For example, we translate
%
% :- pred p(T1).
% :- pred q(T2).
% :- pred r(T3).
% p(X) :- q([X]), r(0).
%
% into
%
% :- pred p(T1, pred(T1, T1)).
% :- pred q(T2, pred(T2, T2)).
% :- pred r(T3, pred(T2, T2)).
% p(X, Unify) :- q([X], list_unify(Unify)), r(0, int_unify).
%
% (except that both the input and output of the transformation are
% actually in super-homogeneous form).
%-----------------------------------------------------------------------------%
:- module polymorphism.
:- interface.
:- import_module hlds.
:- pred polymorphism__process_module(module_info, module_info).
:- mode polymorphism__process_module(in, out) is det.
%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%
:- implementation.
:- import_module int, string, list, set, map, term, varset, std_util, require.
:- import_module prog_io, type_util, mode_util, quantification.
:- import_module code_util, unify_proc.
%-----------------------------------------------------------------------------%
% This whole section just traverses the module structure.
% We do two passes, the first to fix up the procedure bodies,
% (and in fact everything except the pred_info argtypes),
% the second to fix up the pred_info argtypes.
% The reason we need two passes is that the first pass looks at
% the argtypes of the called predicates, and so we need to make
% sure we don't much them up before we've finished the first pass.
polymorphism__process_module(ModuleInfo0, ModuleInfo) :-
module_info_preds(ModuleInfo0, Preds),
map__keys(Preds, PredIds),
polymorphism__process_preds(PredIds, ModuleInfo0, ModuleInfo1),
polymorphism__fixup_preds(PredIds, ModuleInfo1, ModuleInfo).
:- pred polymorphism__process_preds(list(pred_id), module_info, module_info).
:- mode polymorphism__process_preds(in, in, out) is det.
polymorphism__process_preds([], ModuleInfo, ModuleInfo).
polymorphism__process_preds([PredId | PredIds], ModuleInfo0, ModuleInfo) :-
module_info_pred_info(ModuleInfo0, PredId, PredInfo),
pred_info_name(PredInfo, PredName),
( PredName = "call" ->
ModuleInfo1 = ModuleInfo0
;
pred_info_procids(PredInfo, ProcIds),
polymorphism__process_procs(PredId, ProcIds, ModuleInfo0,
ModuleInfo1)
),
polymorphism__process_preds(PredIds, ModuleInfo1, ModuleInfo).
:- pred polymorphism__process_procs(pred_id, list(proc_id),
module_info, module_info).
:- mode polymorphism__process_procs(in, in, in, out) is det.
polymorphism__process_procs(_PredId, [], ModuleInfo, ModuleInfo).
polymorphism__process_procs(PredId, [ProcId | ProcIds], ModuleInfo0,
ModuleInfo) :-
module_info_preds(ModuleInfo0, PredTable0),
map__lookup(PredTable0, PredId, PredInfo0),
pred_info_procedures(PredInfo0, ProcTable0),
map__lookup(ProcTable0, ProcId, ProcInfo0),
polymorphism__process_proc(ProcInfo0, PredInfo0, ModuleInfo0,
ProcInfo, PredInfo1),
map__set(ProcTable0, ProcId, ProcInfo, ProcTable),
pred_info_set_procedures(PredInfo1, ProcTable, PredInfo),
map__set(PredTable0, PredId, PredInfo, PredTable),
module_info_set_preds(ModuleInfo0, PredTable, ModuleInfo1),
polymorphism__process_procs(PredId, ProcIds, ModuleInfo1, ModuleInfo).
%---------------------------------------------------------------------------%
:- pred polymorphism__fixup_preds(list(pred_id), module_info, module_info).
:- mode polymorphism__fixup_preds(in, in, out) is det.
polymorphism__fixup_preds([], ModuleInfo, ModuleInfo).
polymorphism__fixup_preds([PredId | PredIds], ModuleInfo0, ModuleInfo) :-
%
% Recompute the arg types by finding the headvars and the var->type
% mapping (from the first procedure for the predicate) and
% applying the type mapping to the extra headvars to get the new
% arg types. Note that we are careful to only apply the mapping
% to the extra head vars, not to the originals, because otherwise
% we would stuff up the arg types for unification predicates for
% equivalence types.
%
module_info_preds(ModuleInfo0, PredTable0),
map__lookup(PredTable0, PredId, PredInfo0),
pred_info_procedures(PredInfo0, ProcTable0),
pred_info_proc_ids(PredInfo0, ProcIds),
( ProcIds = [ProcId|_] ->
map__lookup(ProcTable0, ProcId, ProcInfo),
proc_info_vartypes(ProcInfo, VarTypes),
proc_info_headvars(ProcInfo, HeadVars),
pred_info_arg_types(PredInfo0, TypeVarSet, ArgTypes0),
list__length(ArgTypes0, NumOldArgs),
list__length(HeadVars, NumNewArgs),
NumExtraArgs is NumNewArgs - NumOldArgs,
(
list__split_list(NumExtraArgs, HeadVars, ExtraHeadVars,
_OldHeadVars)
->
map__apply_to_list(ExtraHeadVars, VarTypes,
ExtraArgTypes),
list__append(ExtraArgTypes, ArgTypes0, ArgTypes)
;
error("polymorphism.nl: list__split_list failed")
),
pred_info_set_arg_types(PredInfo0, TypeVarSet, ArgTypes,
PredInfo),
map__set(PredTable0, PredId, PredInfo, PredTable),
module_info_set_preds(ModuleInfo0, PredTable, ModuleInfo1),
polymorphism__fixup_preds(PredIds, ModuleInfo1, ModuleInfo)
;
ModuleInfo = ModuleInfo0
).
%---------------------------------------------------------------------------%
:- type poly_info --->
poly_info(
varset, % from the proc_info
map(var, type), % from the proc_info
tvarset, % from the proc_info
map(tvar, var), % specifies the unify proc var
% for each of the pred's type
% parameters
module_info
).
:- pred polymorphism__process_proc(proc_info, pred_info, module_info,
proc_info, pred_info).
:- mode polymorphism__process_proc(in, in, in, out, out) is det.
polymorphism__process_proc(ProcInfo0, PredInfo0, ModuleInfo,
ProcInfo, PredInfo) :-
% grab the appropriate fields from the pred_info and proc_info
pred_info_arg_types(PredInfo0, ArgTypeVarSet, ArgTypes),
pred_info_typevarset(PredInfo0, TypeVarSet0),
proc_info_headvars(ProcInfo0, HeadVars0),
proc_info_variables(ProcInfo0, VarSet0),
proc_info_vartypes(ProcInfo0, VarTypes0),
proc_info_goal(ProcInfo0, Goal0),
proc_info_argmodes(ProcInfo0, ArgModes0),
% insert extra head variables to hold the address of the
% equality predicate for each polymorphic type in the predicate's
% type declaration
term__vars_list(ArgTypes, HeadTypeVars0),
list__sort(HeadTypeVars0, HeadTypeVars), % remove duplicates
polymorphism__make_head_vars(HeadTypeVars, ArgTypeVarSet,
VarSet0, VarTypes0,
ExtraHeadVars, VarSet1, VarTypes1),
list__append(ExtraHeadVars, HeadVars0, HeadVars),
list__length(ExtraHeadVars, NumExtraVars),
list__duplicate(NumExtraVars, ground -> ground, ExtraModes),
list__append(ExtraModes, ArgModes0, ArgModes),
pred_info_name(PredInfo0, PredName),
( PredName = "call" ->
VarTypes = VarTypes1,
VarSet = VarSet1,
TypeVarSet = TypeVarSet0,
Goal = Goal0
;
% process any polymorphic calls inside the goal
map__from_corresponding_lists(HeadTypeVars, ExtraHeadVars,
UnifyProcMap),
Info0 = poly_info(VarSet1, VarTypes1, TypeVarSet0,
UnifyProcMap, ModuleInfo),
polymorphism__process_goal(Goal0, Goal1, Info0, Info),
Info = poly_info(VarSet, VarTypes, TypeVarSet, _, _),
% if we introduced any new head variables, we need to
% fix up the quantification (non-local variables)
( ExtraHeadVars = [] ->
Goal = Goal1
;
implicitly_quantify_clause_body(HeadVars, Goal1, Goal)
)
),
% set the new values of the fields in proc_info and pred_info
proc_info_set_headvars(ProcInfo0, HeadVars, ProcInfo1),
proc_info_set_goal(ProcInfo1, Goal, ProcInfo2),
proc_info_set_varset(ProcInfo2, VarSet, ProcInfo3),
proc_info_set_vartypes(ProcInfo3, VarTypes, ProcInfo4),
proc_info_set_argmodes(ProcInfo4, ArgModes, ProcInfo),
pred_info_set_typevarset(PredInfo0, TypeVarSet, PredInfo).
:- pred polymorphism__process_goal(hlds__goal, hlds__goal,
poly_info, poly_info).
:- mode polymorphism__process_goal(in, out, in, out) is det.
polymorphism__process_goal(Goal0 - GoalInfo0, Goal) -->
polymorphism__process_goal_2(Goal0, GoalInfo0, Goal).
:- pred polymorphism__process_goal_2(hlds__goal_expr, hlds__goal_info,
hlds__goal, poly_info, poly_info).
:- mode polymorphism__process_goal_2(in, in, out, in, out) is det.
polymorphism__process_goal_2(
call(PredId, ProcId, Args0, Builtin, Name, FollowVars),
GoalInfo, Goal) -->
{ term__term_list_to_var_list(Args0, ArgVars0) },
polymorphism__process_call(PredId, ProcId, ArgVars0,
ArgVars, ExtraGoals),
{ term__var_list_to_term_list(ArgVars, Args) },
{ Call = call(PredId, ProcId, Args, Builtin, Name, FollowVars)
- GoalInfo },
{ list__append(ExtraGoals, [Call], GoalList) },
{ conj_list_to_goal(GoalList, GoalInfo, Goal) }.
polymorphism__process_goal_2(unify(X, Y, Mode, Unification, Context), GoalInfo,
Goal) -->
(
{ Unification = complicated_unify(UniMode, _Category,
FollowVars) },
{ X = term__variable(XVar) }
->
=(poly_info(_, VarTypes, _, UnifyProcMap, ModuleInfo)),
{ map__lookup(VarTypes, XVar, Type) },
( { Type = term__variable(TypeVar) } ->
% Convert polymorphic unifications into calls to
% call(UnifyProcVar, X, Y)
% where UnifyProcVar is the higher-order pred var
% associated with the type of the variables that
% are being unified.
{ module_info_get_predicate_table(ModuleInfo,
PredicateTable) },
{ predicate_table_search_name_arity(PredicateTable,
"call", 3, [CallPredId]) ->
PredId = CallPredId
;
error("polymorphism.nl: can't find `call/3'")
},
{ ProcId = 0 },
{ map__lookup(UnifyProcMap, TypeVar, UnifyProcVar) },
{ SymName = unqualified("call") },
{ Args = [term__variable(UnifyProcVar), X, Y] },
{ code_util__is_builtin(ModuleInfo, PredId, ProcId,
IsBuiltin) },
{ Goal = call(PredId, ProcId, Args, IsBuiltin,
SymName, FollowVars) - GoalInfo }
; { type_to_type_id(Type, TypeId, _) } ->
% Convert other complicated unifications into
% calls to unification predicates, and then
% recursively call polymorphism__process_goal_2
% to insert extra arguments if necessary.
{ module_info_get_unify_pred_map(ModuleInfo,
UnifyPredMap) },
{ map__lookup(UnifyPredMap, TypeId, PredId) },
% We handle (in, in) unifications specially - they
% are always mode zero
{ UniMode = (XInitial - YInitial -> _Final) },
(
{ inst_is_ground(ModuleInfo, XInitial) },
{ inst_is_ground(ModuleInfo, YInitial) }
->
{ ProcId = 0 }
;
{ XInitial = not_reached }
->
{ ProcId = 0 }
;
{ YInitial = not_reached }
->
{ ProcId = 0 }
;
{ module_info_get_unify_requests(ModuleInfo,
UnifyRequests) },
{ unify_proc__lookup_num(UnifyRequests,
TypeId, UniMode, ProcId) }
),
{ SymName = unqualified("=") },
{ Args = [X, Y] },
{ Call = call(PredId, ProcId, Args, not_builtin,
SymName, FollowVars) },
polymorphism__process_goal_2(Call, GoalInfo, Goal)
;
{ error("polymorphism: type_to_type_id failed") }
)
;
% ordinary unifications are left unchanged
{ Goal = unify(X, Y, Mode, Unification, Context) - GoalInfo }
).
% the rest of the clauses just process goals recursively
polymorphism__process_goal_2(conj(Goals0), GoalInfo, conj(Goals) - GoalInfo) -->
polymorphism__process_goal_list(Goals0, Goals).
polymorphism__process_goal_2(disj(Goals0), GoalInfo, disj(Goals) - GoalInfo) -->
polymorphism__process_goal_list(Goals0, Goals).
polymorphism__process_goal_2(not(Goal0), GoalInfo, not(Goal) - GoalInfo) -->
polymorphism__process_goal(Goal0, Goal).
polymorphism__process_goal_2(switch(_, _, _), _, _) -->
{ error("polymorphism__process_goal_2: switch unexpected") }.
polymorphism__process_goal_2(some(Vars, Goal0), GoalInfo,
some(Vars, Goal) - GoalInfo) -->
polymorphism__process_goal(Goal0, Goal).
polymorphism__process_goal_2(if_then_else(Vars, A0, B0, C0), GoalInfo,
if_then_else(Vars, A, B, C) - GoalInfo) -->
polymorphism__process_goal(A0, A),
polymorphism__process_goal(B0, B),
polymorphism__process_goal(C0, C).
:- pred polymorphism__process_goal_list(list(hlds__goal), list(hlds__goal),
poly_info, poly_info).
:- mode polymorphism__process_goal_list(in, out, in, out) is det.
polymorphism__process_goal_list([], []) --> [].
polymorphism__process_goal_list([Goal0 | Goals0], [Goal | Goals]) -->
polymorphism__process_goal(Goal0, Goal),
polymorphism__process_goal_list(Goals0, Goals).
:- pred polymorphism__process_call(pred_id, proc_id, list(var),
list(var), list(hlds__goal),
poly_info, poly_info).
:- mode polymorphism__process_call(in, in, in, out, out, in, out) is det.
polymorphism__process_call(PredId, _ProcId, ArgVars0, ArgVars, ExtraGoals,
Info0, Info) :-
Info0 = poly_info(VarSet0, VarTypes0, TypeVarSet0,
UnifyProcMap, ModuleInfo),
module_info_pred_info(ModuleInfo, PredId, PredInfo),
pred_info_arg_types(PredInfo, PredTypeVarSet, PredArgTypes0),
% rename apart
% (this merge might be a performance bottleneck?)
varset__merge(TypeVarSet0, PredTypeVarSet, PredArgTypes0,
TypeVarSet, PredArgTypes),
term__vars_list(PredArgTypes, PredTypeVars0),
( PredTypeVars0 = [] ->
% optimize for common case of non-polymorphic call
ArgVars = ArgVars0,
ExtraGoals = [],
Info = Info0
;
list__sort(PredTypeVars0, PredTypeVars), % eliminate duplicates
map__apply_to_list(ArgVars0, VarTypes0, ActualArgTypes),
map__keys(UnifyProcMap, HeadTypeVars),
map__init(TypeSubst0),
( type_unify_list(ActualArgTypes, PredArgTypes, HeadTypeVars,
TypeSubst0, TypeSubst1) ->
TypeSubst = TypeSubst1
;
error("polymorphism__process_goal_2: type unification failed")
),
term__var_list_to_term_list(PredTypeVars, PredTypes0),
term__apply_rec_substitution_to_list(PredTypes0, TypeSubst,
PredTypes),
polymorphism__make_vars(PredTypes, ModuleInfo, UnifyProcMap,
VarSet0, VarTypes0,
ExtraVars, ExtraGoals, VarSet, VarTypes),
list__append(ExtraVars, ArgVars0, ArgVars),
Info = poly_info(VarSet, VarTypes, TypeVarSet,
UnifyProcMap, ModuleInfo)
).
%---------------------------------------------------------------------------%
:- pred polymorphism__make_vars(list(type), module_info,
map(tvar, var), varset, map(var, type),
list(var), list(hlds__goal),
varset, map(var, type)).
:- mode polymorphism__make_vars(in, in, in, in, in, out, out, out, out) is det.
polymorphism__make_vars([], _, _, VarSet, VarTypes, [], [], VarSet, VarTypes).
polymorphism__make_vars([Type|Types], ModuleInfo, UnifyProcMap,
VarSet0, VarTypes0,
ExtraVars, ExtraGoals, VarSet, VarTypes) :-
(
type_to_type_id(Type, _TypeId, TypeArgs)
->
% This occurs for code where a predicate calls a polymorphic
% predicate with a known value of the type variable.
% For example, given
%
% :- pred p(T1).
% :- pred q(T2).
% :- pred r(T3).
% p(X) :- q([X]), r(0).
%
% we know that in the call to q/1, T2 is bound to `list(T1)',
% and in the call to r/1, T3 is bound to `int', and so
% we translate it into
% :- pred p(T1, pred(T1, T1)).
% :- pred q(T2, pred(T2, T2)).
% :- pred r(T3, pred(T3, T3)).
% p(X, Unify) :- q([X], list_unify(Unify)), r(int_unify).
% create a term which holds the unification pred for
% the type, processing any argument types recursively
polymorphism__make_vars(TypeArgs, ModuleInfo, UnifyProcMap,
VarSet0, VarTypes0,
ArgVars, ExtraGoals0, VarSet1, VarTypes1),
term__var_list_to_term_list(ArgVars, Args),
Functor = term__atom("="),
term__context_init(Context),
ValTerm = term__functor(Functor, Args, Context),
classify_type(Type, ModuleInfo, TypeCategory),
polymorphism__get_unify_proc(TypeCategory, ModuleInfo, ConsId),
% introduce new variable
varset__new_var(VarSet1, Var, VarSet2),
UnifyPredType = term__functor(term__atom("pred"),
[Type, Type],
Context),
map__set(VarTypes1, Var, UnifyPredType, VarTypes2),
VarTerm = term__variable(Var),
% create a construction unification which initializes the
% variable to the unification pred for the type
UniMode = (free - ground -> ground - ground),
list__length(ArgVars, NumArgVars),
list__duplicate(NumArgVars, UniMode, UniModes),
Unification = construct(Var, ConsId, ArgVars, UniModes),
UnifyMode = (free -> ground) - (ground -> ground),
UnifyContext = unify_context(explicit, []),
% XXX the UnifyContext is wrong
Unify = unify(VarTerm, ValTerm, UnifyMode, Unification,
UnifyContext),
% create a goal_info for the unification
goal_info_init(GoalInfo0),
set__list_to_set([Var | ArgVars], NonLocals),
goal_info_set_nonlocals(GoalInfo0, NonLocals, GoalInfo1),
map__init(InstMapping0),
list__duplicate(NumArgVars, ground, ArgInsts),
% note that we could perhaps be more accurate than
% `ground', but hopefully it shouldn't make any
% difference.
map__set(InstMapping0, Var, bound([functor(Functor, ArgInsts)]),
InstMapping),
goal_info_set_instmap_delta(GoalInfo1, reachable(InstMapping),
GoalInfo),
ExtraGoal = Unify - GoalInfo,
list__append(ExtraGoals0, [ExtraGoal], ExtraGoals1)
;
Type = term__variable(TypeVar1),
map__search(UnifyProcMap, TypeVar1, UnifyProcVar)
->
% This occurs for code where a predicate calls a polymorphic
% predicate with a bound but unknown value of the type variable.
% For example, in
%
% :- pred p(T1).
% :- pred q(T2).
% p(X) :- q(X).
%
% we know that `T2' is bound to `T1', and we translate it into
%
% :- pred p(T1, pred(T1, T1)).
% :- pred q(T2, pred(T2, T2)).
% p(X, UnifyProc) :- q(X, UnifyProc).
Var = UnifyProcVar,
ExtraGoals1 = [],
VarSet2 = VarSet0,
VarTypes2 = VarTypes0
;
% This occurs for code where a predicate calls a polymorphic
% predicate with an unbound type variable, for example
%
% :- pred p.
% :- pred q(list(T)).
% p :- q([]).
%
% In this case T is unbound, so there cannot be any objects
% ot type T, and so q/1 cannot possibly use the unification
% predicate for type T. We just pass a dummy value (zero).
%
% :- pred p.
% :- pred q(T, pred(T, T)).
% p :- q([], 0).
%
% (This isn't really type-correct, but we're already past
% the type-checker. Passing 0 should ensure that we get
% a core dump if we ever attempt to call the unify pred.)
% introduce new variable
varset__new_var(VarSet0, Var, VarSet2),
UnifyPredType = term__functor(term__atom("pred"),
[Type, Type],
Context),
map__set(VarTypes0, Var, UnifyPredType, VarTypes2),
VarTerm = term__variable(Var),
% create a construction unification which initializes the
% variable to zero
term__context_init(Context),
Functor = term__integer(0),
ZeroTerm = term__functor(Functor, [], Context),
ConsId = int_const(0),
Unification = construct(Var, ConsId, [], []),
UnifyMode = (free -> ground) - (ground -> ground),
UnifyContext = unify_context(explicit, []),
% XXX the UnifyContext is wrong
Unify = unify(VarTerm, ZeroTerm, UnifyMode, Unification,
UnifyContext),
goal_info_init(GoalInfo0),
set__singleton_set(NonLocals, Var),
goal_info_set_nonlocals(GoalInfo0, NonLocals, GoalInfo1),
map__init(InstMapping0),
map__set(InstMapping0, Var, bound([functor(Functor, [])]),
InstMapping),
goal_info_set_instmap_delta(GoalInfo1, reachable(InstMapping),
GoalInfo),
Goal = Unify - GoalInfo,
ExtraGoals1 = [Goal]
),
ExtraVars = [Var | ExtraVars1],
list__append(ExtraGoals1, ExtraGoals2, ExtraGoals),
polymorphism__make_vars(Types, ModuleInfo, UnifyProcMap,
VarSet2, VarTypes2,
ExtraVars1, ExtraGoals2, VarSet, VarTypes).
:- pred polymorphism__get_unify_proc(builtin_type, module_info, cons_id).
:- mode polymorphism__get_unify_proc(in, in, out) is det.
polymorphism__get_unify_proc(int_type, ModuleInfo, ConsId) :-
polymorphism__get_proc("builtin_unify_int", ModuleInfo, ConsId).
polymorphism__get_unify_proc(char_type, ModuleInfo, ConsId) :-
polymorphism__get_proc("builtin_unify_int", ModuleInfo, ConsId).
polymorphism__get_unify_proc(enum_type, ModuleInfo, ConsId) :-
polymorphism__get_proc("builtin_unify_int", ModuleInfo, ConsId).
polymorphism__get_unify_proc(str_type, ModuleInfo, ConsId) :-
polymorphism__get_proc("builtin_unify_string", ModuleInfo, ConsId).
/*
polymorphism__get_unify_proc(float_type, ModuleInfo, ConsId) :-
polymorphism__get_proc("builtin_unify_float", ModuleInfo, ConsId).
*/
polymorphism__get_unify_proc(pred_type, ModuleInfo, ConsId) :-
polymorphism__get_proc("builtin_unify_pred", ModuleInfo, ConsId).
polymorphism__get_unify_proc(polymorphic_type, _ModuleInfo, _ConsId) :-
error("polymorphism__get_unify_proc: polymorphic type").
polymorphism__get_unify_proc(user_type(Type), ModuleInfo, ConsId) :-
module_info_get_unify_pred_map(ModuleInfo, UnifyPredMap),
( type_to_type_id(Type, TypeId, _TypeArgs) ->
map__lookup(UnifyPredMap, TypeId, UnifyPredId),
ConsId = pred_const(UnifyPredId, 0)
;
error("polymorphism__get_unify_proc: type_to_type_id failed")
).
% find the unification procedure with the specified name
:- pred polymorphism__get_proc(string, module_info, cons_id).
:- mode polymorphism__get_proc(in, in, out) is det.
polymorphism__get_proc(Name, ModuleInfo, ConsId) :-
module_info_get_predicate_table(ModuleInfo, PredicateTable),
(
predicate_table_search_name_arity(PredicateTable, Name, 2,
[PredId])
->
ConsId = pred_const(PredId, 0)
;
error("polymorphism__get_proc: lookup failed")
).
:- pred polymorphism__make_head_vars(list(tvar), tvarset,
varset, map(var, type),
list(var), varset, map(var, type)).
:- mode polymorphism__make_head_vars(in, in, in, in, out, out, out) is det.
polymorphism__make_head_vars([], _, VarSet, VarTypes, [], VarSet, VarTypes).
polymorphism__make_head_vars([TypeVar|TypeVars], TypeVarSet,
VarSet0, VarTypes0,
UnifyProcVars, VarSet, VarTypes) :-
varset__new_var(VarSet0, Var, VarSet1),
( varset__lookup_name(TypeVarSet, TypeVar, TypeVarName) ->
string__append("Unify__", TypeVarName, VarName),
varset__name_var(VarSet1, Var, VarName, VarSet2)
;
VarSet2 = VarSet1
),
term__context_init(Context),
Type = term__variable(TypeVar),
UnifyPredType = term__functor(term__atom("pred"), [Type, Type],
Context),
map__set(VarTypes0, Var, UnifyPredType, VarTypes1),
UnifyProcVars = [Var | UnifyProcVars1],
polymorphism__make_head_vars(TypeVars, TypeVarSet,
VarSet2, VarTypes1,
UnifyProcVars1, VarSet, VarTypes).
%---------------------------------------------------------------------------%
%---------------------------------------------------------------------------%