Rename the types 'type', 'inst' and 'mode' to 'mer_type', 'mer_inst'

Estimated hours taken: 8
Branches: main

compiler/*.m:
	Rename the types 'type', 'inst' and 'mode' to 'mer_type', 'mer_inst'
	and 'mer_mode'. This is to avoid the need to parenthesize these type
	names in some contexts, and to prepare for the possibility of a parser
	that considers those words to be reserved words.

	Rename some other uses of those names (e.g. as item types in
	recompilation.m).

	Delete some redundant synonyms (prog_type, mercury_type) for mer_type.

	Change some type names (e.g. mlds__type) and predicate names (e.g.
	deforest__goal) to make them unique even without module qualification.

	Rename the function symbols (e.g. pure, &) that need to be renamed
	to avoid the need to parenthesize them. Make their replacement names
	more expressive.

	Convert some more modules to four space indentation.

	Avoid excessively long lines, such as those resulting from the
	automatic substitution of 'mer_type' for 'type'.

compiler/prog_io_util.m

@@ -108,11 +108,11 @@
 :- pred parse_pred_or_func_and_args(term(_T)::in, pred_or_func::out,
     sym_name::out, list(term(_T))::out) is semidet.
 
-:- pred parse_type(term::in, maybe1(type)::out) is det.
+:- pred parse_type(term::in, maybe1(mer_type)::out) is det.
 
-:- pred parse_types(list(term)::in, maybe1(list(type))::out) is det.
+:- pred parse_types(list(term)::in, maybe1(list(mer_type))::out) is det.
 
-:- pred unparse_type((type)::in, term::out) is det.
+:- pred unparse_type(mer_type::in, term::out) is det.
 
 :- pred parse_purity_annotation(term(T)::in, purity::out, term(T)::out) is det.
 
@@ -121,15 +121,15 @@
     ;       no_allow_constrained_inst_var.
 
 :- pred convert_mode_list(allow_constrained_inst_var::in, list(term)::in,
-    list(mode)::out) is semidet.
+    list(mer_mode)::out) is semidet.
 
-:- pred convert_mode(allow_constrained_inst_var::in, term::in, (mode)::out)
+:- pred convert_mode(allow_constrained_inst_var::in, term::in, mer_mode::out)
     is semidet.
 
 :- pred convert_inst_list(allow_constrained_inst_var::in, list(term)::in,
-    list(inst)::out) is semidet.
+    list(mer_inst)::out) is semidet.
 
-:- pred convert_inst(allow_constrained_inst_var::in, term::in, (inst)::out)
+:- pred convert_inst(allow_constrained_inst_var::in, term::in, mer_inst::out)
     is semidet.
 
 :- pred standard_det(string::in, determinism::out) is semidet.
@@ -312,8 +312,8 @@ parse_type(Term, Result) :-
 parse_types(Terms, Result) :-
     parse_types_2(Terms, [], Result).
 
-:- pred parse_types_2(list(term)::in, list(type)::in, maybe1(list(type))::out)
-    is det.
+:- pred parse_types_2(list(term)::in, list(mer_type)::in,
+    maybe1(list(mer_type))::out) is det.
 
 parse_types_2([], RevTypes, ok(Types)) :-
     list__reverse(RevTypes, Types).
@@ -337,8 +337,8 @@ parse_builtin_type(Term, BuiltinType) :-
     % The predicate parse_type will then try to parse the term as an ordinary
     % defined type and will produce the required error message.
     %
-:- pred parse_higher_order_type(term::in, list(type)::out, maybe(type)::out,
-    purity::out, lambda_eval_method::out) is semidet.
+:- pred parse_higher_order_type(term::in, list(mer_type)::out,
+    maybe(mer_type)::out, purity::out, lambda_eval_method::out) is semidet.
 
 parse_higher_order_type(Term0, ArgTypes, MaybeRet, Purity, EvalMethod) :-
     parse_purity_annotation(Term0, Purity, Term1),
@@ -362,7 +362,7 @@ parse_purity_annotation(Term0, Purity, Term) :-
         Purity = Purity0,
         Term = Term1
     ;
-        Purity = (pure),
+        Purity = purity_pure,
         Term = Term0
     ).
 
@@ -403,7 +403,7 @@ unparse_type(apply_n(TVar, Args, _), Term) :-
 unparse_type(kinded(_, _), _) :-
     unexpected(this_file, "prog_io_util: kind annotation").
 
-:- pred unparse_type_list(list(type)::in, list(term)::out) is det.
+:- pred unparse_type_list(list(mer_type)::in, list(term)::out) is det.
 
 unparse_type_list(Types, Terms) :-
     list__map(unparse_type, Types, Terms).
@@ -422,18 +422,18 @@ unparse_qualified_term(qualified(Qualifier, Name), Args, Term) :-
 :- pred maybe_add_lambda_eval_method(lambda_eval_method::in, term::in,
     term::out) is det.
 
-maybe_add_lambda_eval_method(normal, Term, Term).
-maybe_add_lambda_eval_method((aditi_bottom_up), Term0, Term) :-
+maybe_add_lambda_eval_method(lambda_normal, Term, Term).
+maybe_add_lambda_eval_method(lambda_aditi_bottom_up, Term0, Term) :-
     Context = term__context_init,
     Term = term__functor(term__atom("aditi_bottom_up"), [Term0], Context).
 
 :- pred maybe_add_purity_annotation(purity::in, term::in, term::out) is det.
 
-maybe_add_purity_annotation(pure, Term, Term).
-maybe_add_purity_annotation((semipure), Term0, Term) :-
+maybe_add_purity_annotation(purity_pure, Term, Term).
+maybe_add_purity_annotation(purity_semipure, Term0, Term) :-
     Context = term__context_init,
     Term = term__functor(term__atom("semipure"), [Term0], Context).
-maybe_add_purity_annotation((impure), Term0, Term) :-
+maybe_add_purity_annotation(purity_impure, Term0, Term) :-
     Context = term__context_init,
     Term = term__functor(term__atom("impure"), [Term0], Context).
 
@@ -590,13 +590,13 @@ convert_inst(AllowConstrainedInstVar, Term, Result) :-
     % A "simple" builtin inst is one that has no arguments and no special
     % syntax.
     %
-:- pred convert_simple_builtin_inst(string::in, list(term)::in, (inst)::out)
+:- pred convert_simple_builtin_inst(string::in, list(term)::in, mer_inst::out)
     is semidet.
 
 convert_simple_builtin_inst(Name, [], Inst) :-
     convert_simple_builtin_inst_2(Name, Inst).
 
-:- pred convert_simple_builtin_inst_2(string::in, (inst)::out) is semidet.
+:- pred convert_simple_builtin_inst_2(string::in, mer_inst::out) is semidet.
 
     % `free' insts
 convert_simple_builtin_inst_2("free", free).
@@ -630,7 +630,7 @@ standard_det("erroneous", erroneous).
 standard_det("failure", failure).
 
 :- pred parse_bound_inst_list(allow_constrained_inst_var::in, term::in,
-    uniqueness::in, (inst)::out) is semidet.
+    uniqueness::in, mer_inst::out) is semidet.
 
 parse_bound_inst_list(AllowConstrainedInstVar, Disj, Uniqueness,
         bound(Uniqueness, Functors)) :-