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mercury/compiler/field_access.m
Zoltan Somogyi 1abc2f39a0 Continue the breakup of the monster module prog_io.m.
Estimated hours taken: 3
Branches: main

Continue the breakup of the monster module prog_io.m.

compiler/prog_io.m:
compiler/prog_io_mutable.m:
compiler/prog_io_sym_name.m:
	Move the code in prog_io.m for dealing with declarations for mutables
	and for parsing symbol names and specifiers into two new modules.

compiler/parse_tree.m:
compiler/notes/compiler_design.html:
	Add the new modules.

compiler/*.m:
	Import prog_io_sym_name instead of (or, in a couple of cases, as well
	as) prog_io.
2008-12-02 04:30:29 +00:00

352 lines
15 KiB
Mathematica

%-----------------------------------------------------------------------------%
% vim: ft=mercury ts=4 sw=4 et
%-----------------------------------------------------------------------------%
% Copyright (C) 1993-2006, 2008 The University of Melbourne.
% This file may only be copied under the terms of the GNU General
% Public License - see the file COPYING in the Mercury distribution.
%-----------------------------------------------------------------------------%
%
% File: field_access.
%
% This submodule of make_hlds handles the declarations of fields
%
%-----------------------------------------------------------------------------%
:- module hlds.make_hlds.field_access.
:- interface.
:- import_module hlds.hlds_goal.
:- import_module hlds.hlds_module.
:- import_module hlds.make_hlds.qual_info.
:- import_module hlds.make_hlds.state_var.
:- import_module hlds.make_hlds.superhomogeneous.
:- import_module parse_tree.error_util.
:- import_module parse_tree.prog_data.
:- import_module parse_tree.prog_io_util.
:- import_module assoc_list.
:- import_module list.
:- import_module pair.
%-----------------------------------------------------------------------------%
:- type field_list == assoc_list(ctor_field_name, list(prog_term)).
% Expand a field update goal into a list of goals which each get or set
% one level of the structure.
%
% A field update goal:
% Term = Term0 ^ module_info ^ ctors := Ctors
% is expanded into
% V_1 = Term0 ^ module_info,
% V_3 = V_2 ^ ctors := Ctors,
% Term = Term0 ^ module_info := V_3.
%
:- pred expand_set_field_function_call(prog_context::in,
unify_main_context::in, unify_sub_contexts::in, field_list::in,
prog_var::in, prog_var::in, prog_var::in, cons_id::out,
pair(cons_id, unify_sub_contexts)::out, hlds_goal::out,
num_added_goals::out, prog_varset::in, prog_varset::out,
module_info::in, module_info::out, qual_info::in, qual_info::out,
svar_info::in, svar_info::out,
list(error_spec)::in, list(error_spec)::out) is det.
% Expand a field extraction goal into a list of goals which each get one
% level of the structure.
%
% A field extraction goal:
% := (ModuleName, ^ module_info ^ sub_info ^ module_name,
% DCG_in, DCG_out).
% is expanded into
% DCG_out = DCG_in,
% V_1 = DCG_out ^ module_info
% V_2 = V_1 ^ sub_info,
% ModuleName = V_2 ^ module_name.
%
:- pred expand_dcg_field_extraction_goal(prog_context::in,
unify_main_context::in, unify_sub_contexts::in, field_list::in,
prog_var::in, prog_var::in, prog_var::in, cons_id::out,
pair(cons_id, unify_sub_contexts)::out, hlds_goal::out,
num_added_goals::out, prog_varset::in, prog_varset::out,
module_info::in, module_info::out, qual_info::in, qual_info::out,
svar_info::in, svar_info::out,
list(error_spec)::in, list(error_spec)::out) is det.
% Expand a field extraction function call into a list of goals which
% each get one level of the structure.
%
% A field extraction goal:
% ModuleName = Info ^ module_info ^ sub_info ^ module_name
% is expanded into
% V_1 = Info ^ module_info,
% V_2 = V_1 ^ sub_info,
% ModuleName = V_2 ^ module_name.
%
:- pred expand_get_field_function_call(prog_context::in,
unify_main_context::in, unify_sub_contexts::in, field_list::in,
prog_var::in, prog_var::in, purity::in, cons_id::out,
pair(cons_id, unify_sub_contexts)::out,
hlds_goal::out, num_added_goals::out, prog_varset::in, prog_varset::out,
module_info::in, module_info::out, qual_info::in, qual_info::out,
svar_info::in, svar_info::out,
list(error_spec)::in, list(error_spec)::out) is det.
:- pred maybe_parse_field_list(prog_term::in, prog_varset::in,
field_list::out) is semidet.
:- pred parse_field_list(prog_term::in, prog_varset::in,
list(format_component)::in, maybe1(field_list)::out) is det.
%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%
:- implementation.
:- import_module hlds.hlds_data.
:- import_module hlds.hlds_pred.
:- import_module hlds.make_hlds.superhomogeneous.
:- import_module libs.compiler_util.
:- import_module parse_tree.mercury_to_mercury.
:- import_module parse_tree.prog_io_sym_name.
:- import_module bool.
:- import_module int.
:- import_module term.
:- import_module varset.
%-----------------------------------------------------------------------------%
expand_set_field_function_call(Context, MainContext, SubContext0, FieldNames,
FieldValueVar, TermInputVar, TermOutputVar, Functor, FieldSubContext,
Goal, NumAdded, !VarSet, !ModuleInfo, !QualInfo, !SInfo, !Specs) :-
expand_set_field_function_call_2(Context, MainContext, SubContext0,
FieldNames, FieldValueVar, TermInputVar, TermOutputVar, Functor,
FieldSubContext, Goals, NumAdded,
!VarSet, !ModuleInfo, !QualInfo, !SInfo, !Specs),
goal_info_init(Context, GoalInfo),
conj_list_to_goal(Goals, GoalInfo, Goal).
:- pred expand_set_field_function_call_2(prog_context::in,
unify_main_context::in, unify_sub_contexts::in, field_list::in,
prog_var::in, prog_var::in, prog_var::in, cons_id::out,
pair(cons_id, unify_sub_contexts)::out, list(hlds_goal)::out,
num_added_goals::out, prog_varset::in, prog_varset::out,
module_info::in, module_info::out, qual_info::in, qual_info::out,
svar_info::in, svar_info::out,
list(error_spec)::in, list(error_spec)::out) is det.
expand_set_field_function_call_2(_, _, _, [], _, _, _, _, _, _, _,
!VarSet, !ModuleInfo, !QualInfo, !SInfo, !Specs) :-
unexpected(this_file,
"expand_set_field_function_call_2: empty list of field names").
expand_set_field_function_call_2(Context, MainContext, SubContext0,
[FieldName - FieldArgs | FieldNames], FieldValueVar,
TermInputVar, TermOutputVar, Functor, FieldSubContext, Goals, NumAdded,
!VarSet, !ModuleInfo, !QualInfo, !SInfo, !Specs) :-
make_fresh_arg_vars(FieldArgs, FieldArgVars, !VarSet, !SInfo, !Specs),
(
FieldNames = [_ | _],
varset.new_var(!.VarSet, SubTermInputVar, !:VarSet),
varset.new_var(!.VarSet, SubTermOutputVar, !:VarSet),
SetArgs = FieldArgVars ++ [TermInputVar, SubTermOutputVar],
construct_field_access_function_call(set, Context,
MainContext, SubContext0, FieldName, TermOutputVar,
SetArgs, purity_pure, Functor, UpdateGoal, !QualInfo),
UpdateAdded = 1,
% Extract the field containing the field to update.
construct_field_access_function_call(get, Context,
MainContext, SubContext0, FieldName, SubTermInputVar,
list.append(FieldArgVars, [TermInputVar]), purity_pure, _,
GetSubFieldGoal, !QualInfo),
GetSubFieldAdded = 1,
% Recursively update the field.
SubTermInputArgNumber = 2 + list.length(FieldArgs),
TermInputContext = Functor - SubTermInputArgNumber,
SubContext = [TermInputContext | SubContext0],
expand_set_field_function_call_2(Context, MainContext,
SubContext, FieldNames, FieldValueVar, SubTermInputVar,
SubTermOutputVar, _, FieldSubContext, Goals0, SetAdded,
!VarSet, !ModuleInfo, !QualInfo, !SInfo, !Specs),
FieldAdded = GetSubFieldAdded + SetAdded + UpdateAdded,
Goals1 = [GetSubFieldGoal | Goals0] ++ [UpdateGoal]
;
FieldNames = [],
SetArgs = FieldArgVars ++ [TermInputVar, FieldValueVar],
construct_field_access_function_call(set, Context,
MainContext, SubContext0, FieldName, TermOutputVar,
SetArgs, purity_pure, Functor, Goal, !QualInfo),
FieldAdded = 1,
FieldSubContext = Functor - SubContext0,
Goals1 = [Goal]
),
ArgContext = ac_functor(Functor, MainContext, SubContext0),
goal_info_init(Context, GoalInfo),
conj_list_to_goal(Goals1, GoalInfo, Conj0),
insert_arg_unifications(FieldArgVars, FieldArgs, Context, ArgContext,
Conj0, Conj, ArgAdded, !VarSet, !ModuleInfo, !QualInfo,
!SInfo, !Specs),
NumAdded = FieldAdded + ArgAdded,
goal_to_conj_list(Conj, Goals).
expand_dcg_field_extraction_goal(Context, MainContext, SubContext, FieldNames,
FieldValueVar, TermInputVar, TermOutputVar, Functor, FieldSubContext,
Goal, NumAdded, !VarSet, !ModuleInfo, !QualInfo, !SInfo, !Specs) :-
% Unify the DCG input and output variables.
make_atomic_unification(TermOutputVar, rhs_var(TermInputVar), Context,
MainContext, SubContext, UnifyDCG, !QualInfo),
UnifyAdded = 1,
% Process the access function as a get function on the output DCG variable.
expand_get_field_function_call_2(Context, MainContext, SubContext,
FieldNames, FieldValueVar, TermOutputVar, purity_pure,
Functor, FieldSubContext, Goals1, GetAdded,
!VarSet, !ModuleInfo, !QualInfo, !SInfo, !Specs),
NumAdded = UnifyAdded + GetAdded,
Goals = [UnifyDCG | Goals1],
goal_info_init(Context, GoalInfo),
conj_list_to_goal(Goals, GoalInfo, Goal).
expand_get_field_function_call(Context, MainContext, SubContext0, FieldNames,
FieldValueVar, TermInputVar, Purity, Functor, FieldSubContext,
Goal, NumAdded, !VarSet, !ModuleInfo, !QualInfo, !SInfo, !Specs) :-
expand_get_field_function_call_2(Context, MainContext, SubContext0,
FieldNames, FieldValueVar, TermInputVar, Purity, Functor,
FieldSubContext, Goals, NumAdded, !VarSet, !ModuleInfo, !QualInfo,
!SInfo, !Specs),
goal_info_init(Context, GoalInfo),
conj_list_to_goal(Goals, GoalInfo, Goal).
:- pred expand_get_field_function_call_2(prog_context::in,
unify_main_context::in, unify_sub_contexts::in, field_list::in,
prog_var::in, prog_var::in, purity::in, cons_id::out,
pair(cons_id, unify_sub_contexts)::out, list(hlds_goal)::out,
num_added_goals::out, prog_varset::in, prog_varset::out,
module_info::in, module_info::out, qual_info::in, qual_info::out,
svar_info::in, svar_info::out,
list(error_spec)::in, list(error_spec)::out) is det.
expand_get_field_function_call_2(_, _, _, [], _, _, _, _, _, _, _,
!VarSet, !ModuleInfo, !QualInfo, !Sinfo, !Specs) :-
unexpected(this_file,
"expand_get_field_function_call_2: empty list of field names").
expand_get_field_function_call_2(Context, MainContext, SubContext0,
[FieldName - FieldArgs | FieldNames], FieldValueVar, TermInputVar,
Purity, Functor, FieldSubContext, Goals, NumAdded,
!VarSet, !ModuleInfo, !QualInfo, !SInfo, !Specs) :-
make_fresh_arg_vars(FieldArgs, FieldArgVars, !VarSet, !SInfo, !Specs),
GetArgVars = FieldArgVars ++ [TermInputVar],
(
FieldNames = [_ | _],
varset.new_var(!.VarSet, SubTermInputVar, !:VarSet),
construct_field_access_function_call(get, Context, MainContext,
SubContext0, FieldName, SubTermInputVar, GetArgVars, Purity,
Functor, Goal, !QualInfo),
CallAdded = 1,
% Recursively extract until we run out of field names.
TermInputArgNumber = 1 + list.length(FieldArgVars),
TermInputContext = Functor - TermInputArgNumber,
SubContext = [TermInputContext | SubContext0],
expand_get_field_function_call_2(Context, MainContext,
SubContext, FieldNames, FieldValueVar, SubTermInputVar, Purity,
_, FieldSubContext, Goals1, ExtractAdded, !VarSet, !ModuleInfo,
!QualInfo, !SInfo, !Specs),
Goals2 = [Goal | Goals1],
FieldAdded = CallAdded + ExtractAdded
;
FieldNames = [],
FieldSubContext = Functor - SubContext0,
construct_field_access_function_call(get, Context,
MainContext, SubContext0, FieldName, FieldValueVar,
GetArgVars, Purity, Functor, Goal, !QualInfo),
Goals2 = [Goal],
FieldAdded = 1
),
ArgContext = ac_functor(Functor, MainContext, SubContext0),
goal_info_init(Context, GoalInfo),
conj_list_to_goal(Goals2, GoalInfo, Conj0),
insert_arg_unifications(FieldArgVars, FieldArgs, Context, ArgContext,
Conj0, Conj, ArgAdded, !VarSet, !ModuleInfo, !QualInfo,
!SInfo, !Specs),
NumAdded = FieldAdded + ArgAdded,
goal_to_conj_list(Conj, Goals).
:- pred construct_field_access_function_call(field_access_type::in,
prog_context::in, unify_main_context::in, unify_sub_contexts::in,
ctor_field_name::in, prog_var::in, list(prog_var)::in, purity::in,
cons_id::out, hlds_goal::out, qual_info::in, qual_info::out) is det.
construct_field_access_function_call(AccessType, Context, MainContext,
SubContext, FieldName, RetArg, Args, Purity, Functor, Goal,
!QualInfo) :-
field_access_function_name(AccessType, FieldName, FuncName),
list.length(Args, Arity),
Functor = cons(FuncName, Arity),
make_atomic_unification(RetArg, rhs_functor(Functor, no, Args),
Context, MainContext, SubContext, Purity, Goal, !QualInfo).
maybe_parse_field_list(Term, VarSet, FieldNames) :-
% The value of ContextPieces does not matter, since we succeed
% only if it is not used.
%
% We could construct a dummy VarSet as well, if needed.
ContextPieces = [],
parse_field_list(Term, VarSet, ContextPieces, MaybeFieldNames),
MaybeFieldNames = ok1(FieldNames).
parse_field_list(Term, VarSet, ContextPieces, MaybeFieldNames) :-
(
Term = term.functor(term.atom("^"),
[FieldNameTerm, OtherFieldNamesTerm], _)
->
(
sym_name_and_args(FieldNameTerm, FieldName, Args)
->
parse_field_list(OtherFieldNamesTerm, VarSet, ContextPieces,
MaybeFieldNamesTail),
(
MaybeFieldNamesTail = error1(_),
MaybeFieldNames = MaybeFieldNamesTail
;
MaybeFieldNamesTail = ok1(FieldNamesTail),
MaybeFieldNames = ok1([FieldName - Args | FieldNamesTail])
)
;
Spec = make_field_list_error(VarSet,
get_term_context(FieldNameTerm), Term, ContextPieces),
MaybeFieldNames = error1([Spec])
)
;
( sym_name_and_args(Term, FieldName, Args) ->
MaybeFieldNames = ok1([FieldName - Args])
;
Spec = make_field_list_error(VarSet, get_term_context(Term), Term,
ContextPieces),
MaybeFieldNames = error1([Spec])
)
).
:- func make_field_list_error(prog_varset, term.context, prog_term,
list(format_component)) = error_spec.
make_field_list_error(VarSet, Context, Term, ContextPieces) = Spec :-
TermStr = mercury_term_to_string(VarSet, no, Term),
Pieces = ContextPieces ++ [lower_case_next_if_not_first,
words("Error: expected field name at term"),
quote(TermStr), suffix("."), nl],
Spec = error_spec(severity_error, phase_term_to_parse_tree,
[simple_msg(Context, [always(Pieces)])]).
%-----------------------------------------------------------------------------%
:- func this_file = string.
this_file = "field_access.m".
%-----------------------------------------------------------------------------%
:- end_module field_access.
%-----------------------------------------------------------------------------%