diff: move some useful code out of dnf.m

[Andrew Bromage]

G'day.

Simon Taylor <stayl at cs.mu.OZ.AU> writes:

>Hi Zoltan,

The name's Andrew actually.  I need this change so I'll review it
instead.

>compiler/hlds_pred.m
>	Added predicates proc_info_add_variable and proc_info_add_variables
>	to add a new variable or list of variables given the types.

I think these names are misleading.  They don't capture the fact that
the variable added is _new_.  I can envisage situations where I might
want to add a variable that I've made elsewhere.

Perhaps proc_info_create_var_from_type and proc_info_create_vars_from_types
are a bit more evocative?

>+hlds_pred__define_new_pred(Goal0, Goal, ArgVars, InstMap0, PredName, TVarSet, 
>+		VarTypes, VarSet, Markers, ModuleInfo0,
>+		ModuleInfo, PredProcId) :-
>+	Goal0 = _GoalExpr - GoalInfo,
>+	goal_info_get_instmap_delta(GoalInfo, InstMapDelta),
>+	instmap__apply_instmap_delta(InstMap0, InstMapDelta, InstMap),
>+
>+	goal_info_get_context(GoalInfo, Context),
>+	goal_info_get_determinism(GoalInfo, Detism),
>+	compute_arg_types_modes(ArgVars, VarTypes, InstMap0, InstMap,
>+		ArgTypes, ArgModes),
>+
>+	module_info_name(ModuleInfo0, ModuleName),
>+	SymName = qualified(ModuleName, PredName),
>+	map__init(TVarMap), % later, polymorphism.m will fill this in. 

Should probably document that this must be run after polymorphism.m.

Apart from that, it looks fine to me.

Cheers,
Andrew Bromage