* [Caml-list] Pxp objects inside class definition
@ 2002-07-09 8:35 Gaurav Chanda
2002-07-09 12:20 ` Gerd Stolpmann
0 siblings, 1 reply; 2+ messages in thread
From: Gaurav Chanda @ 2002-07-09 8:35 UTC (permalink / raw)
To: caml-list
Hello
I am using the Polymorphic XML Parser (PXP) to parse XML documents. I have made 2 files : point.ml and point.mli, which contain simple class definitions.
The file point.mli contains:
open Pxp_yacc ;
open Pxp_document ;
open Pxp_types ;
class type point_sig =
object
value mutable x : Pxp_document.node 'a;
end;
class point : point_sig ;
The file point.ml contains:
open Pxp_yacc ;
open Pxp_document ;
open Pxp_types ;
class type point_sig =
object
value mutable x : Pxp_document.node 'a;
end ;
value def = "<def></def>" ;
value def = parse_wfdocument_entity default_config (from_string def) default_spec ;
value defr = def#root ;
class point:point_sig =
object
value mutable x = defr;
end;
I get an error message while compilation. My compilation command is :
ocamlopt -pp "camlp4r pa_extend.cmo" -I +camlp4 -I Ty/ -I /usr/lib/ocaml/site-lib/netstring -I /usr/lib/ocaml/site-lib/pxp-engine -I /usr/lib/ocaml/site-lib/pxp-lex-iso88591/ -c point.mli point.ml
The error message is :
File "point.ml", line 15, characters 8-67:
The class type
object
val mutable x :
('a Pxp_document.node Pxp_document.extension as 'a) Pxp_document.node
end
is not matched by the class type point_sig
The class type
object
val mutable x :
('a Pxp_document.node Pxp_document.extension as 'a) Pxp_document.node
end
is not matched by the class type
object
val mutable x :
('a Pxp_document.node #Pxp_document.extension as 'a) Pxp_document.node
end
The instance variable x has type
(('a Pxp_document.node as 'b) Pxp_document.extension as 'a)
Pxp_document.node =
< add_node : ?force:bool -> 'b -> unit;
add_pinstr : Pxp_dtd.proc_instruction -> unit;
append_node : 'b -> unit; attribute : string -> Pxp_types.att_value;
attribute_names : string list;
attribute_type : string -> Pxp_types.att_type;
attributes : (string * Pxp_types.att_value) list;
attributes_as_nodes : 'b list;
classify_data_node : 'b -> Pxp_document.data_node_classification;
comment : string option; complement_attlist : unit -> unit;
create_data : Pxp_dtd.dtd -> string -> 'b;
create_element : ?name_pool_for_attribute_values:Pxp_types.pool ->
?position:string * int * int ->
?valcheck:bool ->
?att_values:(string * Pxp_types.att_value) list ->
Pxp_dtd.dtd ->
Pxp_document.node_type -> (string * string) list -> 'b;
create_other : ?position:string * int * int ->
Pxp_dtd.dtd -> Pxp_document.node_type -> 'b;
data : string; delete : unit; dtd : Pxp_dtd.dtd;
dump : Format.formatter -> unit; encoding : Pxp_types.rep_encoding;
extension : 'a; id_attribute_name : string;
id_attribute_value : string; idref_attribute_names : string list;
insert_nodes : ?pos:int -> 'b list -> unit;
internal_adopt : 'b option -> int -> unit;
internal_delete : 'b -> unit;
internal_init : string * int * int ->
Pxp_types.pool option ->
bool ->
Pxp_dtd.dtd ->
string ->
(string * string) list ->
(string * Pxp_types.att_value) list -> unit;
internal_init_other : string * int * int ->
Pxp_dtd.dtd -> Pxp_document.node_type -> unit;
internal_set_pos : int -> unit; iter_nodes : ('b -> unit) -> unit;
iter_nodes_sibl : ('b option -> 'b -> 'b option -> unit) -> unit;
local_validate : ?use_dfa:bool ->
?check_data_nodes:bool -> unit -> unit;
localname : string; namespace_info : 'a Pxp_document.namespace_info;
namespace_manager : Pxp_dtd.namespace_manager; namespace_uri :
string; next_node : 'b; node_path : int list; node_position : int;
node_type : Pxp_document.node_type; normprefix : string;
nth_node : int -> 'b; optional_list_attribute : string -> string list;
optional_string_attribute : string -> string option;
orphaned_clone : 'b; orphaned_flat_clone : 'b; parent : 'b;
pinstr : string -> Pxp_dtd.proc_instruction list;
pinstr_names : string list; position : string * int * int;
previous_node : 'b;
quick_set_attributes : (string * Pxp_types.att_value) list -> unit;
remove : unit -> unit;
remove_nodes : ?pos:int -> ?len:int -> unit -> unit;
required_list_attribute : string -> string list;
required_string_attribute : string -> string;
reset_attribute : string -> unit; root : 'b;
set_attribute : ?force:bool -> string -> Pxp_types.att_value -> unit;
set_attributes : (string * Pxp_types.att_value) list -> unit;
set_comment : string option -> unit; set_data : string -> unit;
set_namespace_info : 'a Pxp_document.namespace_info option -> unit;
set_nodes : 'b list -> unit; sub_nodes : 'b list;
validate : unit -> unit; validate_attlist : unit -> unit;
validate_contents : ?use_dfa:bool ->
?check_data_nodes:bool -> unit -> unit;
write : ?prefixes:string list ->
?default:string ->
Pxp_types.output_stream -> Pxp_types.encoding -> unit >
but is expected to have type
('c Pxp_document.node #Pxp_document.extension as 'c) Pxp_document.node =
< add_node : ?force:bool -> 'c Pxp_document.node -> unit;
add_pinstr : Pxp_dtd.proc_instruction -> unit;
append_node : 'c Pxp_document.node -> unit;
attribute : string -> Pxp_types.att_value;
attribute_names : string list;
attribute_type : string -> Pxp_types.att_type;
attributes : (string * Pxp_types.att_value) list;
attributes_as_nodes : 'c Pxp_document.node list;
classify_data_node : 'c Pxp_document.node ->
Pxp_document.data_node_classification;
comment : string option; complement_attlist : unit -> unit;
create_data : Pxp_dtd.dtd -> string -> 'c Pxp_document.node;
create_element : ?name_pool_for_attribute_values:Pxp_types.pool ->
?position:string * int * int ->
?valcheck:bool ->
?att_values:(string * Pxp_types.att_value) list ->
Pxp_dtd.dtd ->
Pxp_document.node_type ->
(string * string) list -> 'c Pxp_document.node;
create_other : ?position:string * int * int ->
Pxp_dtd.dtd ->
Pxp_document.node_type -> 'c Pxp_document.node;
data : string; delete : unit; dtd : Pxp_dtd.dtd;
dump : Format.formatter -> unit; encoding : Pxp_types.rep_encoding;
extension : 'c; id_attribute_name : string;
id_attribute_value : string; idref_attribute_names : string list;
insert_nodes : ?pos:int -> 'c Pxp_document.node list -> unit;
internal_adopt : 'c Pxp_document.node option -> int -> unit;
internal_delete : 'c Pxp_document.node -> unit;
internal_init : string * int * int ->
Pxp_types.pool option ->
bool ->
Pxp_dtd.dtd ->
string ->
(string * string) list ->
(string * Pxp_types.att_value) list -> unit;
internal_init_other : string * int * int ->
Pxp_dtd.dtd -> Pxp_document.node_type -> unit;
internal_set_pos : int -> unit;
iter_nodes : ('c Pxp_document.node -> unit) -> unit;
iter_nodes_sibl : ('c Pxp_document.node option ->
'c Pxp_document.node ->
'c Pxp_document.node option -> unit) ->
unit;
local_validate : ?use_dfa:bool ->
?check_data_nodes:bool -> unit -> unit;
localname : string; namespace_info : 'c Pxp_document.namespace_info;
namespace_manager : Pxp_dtd.namespace_manager; namespace_uri :
string; next_node : 'c Pxp_document.node; node_path : int list;
node_position : int; node_type : Pxp_document.node_type;
normprefix : string; nth_node : int -> 'c Pxp_document.node;
optional_list_attribute : string -> string list;
optional_string_attribute : string -> string option;
orphaned_clone : 'c Pxp_document.node;
orphaned_flat_clone : 'c Pxp_document.node;
parent : 'c Pxp_document.node;
pinstr : string -> Pxp_dtd.proc_instruction list;
pinstr_names : string list; position : string * int * int;
previous_node : 'c Pxp_document.node;
quick_set_attributes : (string * Pxp_types.att_value) list -> unit;
remove : unit -> unit;
remove_nodes : ?pos:int -> ?len:int -> unit -> unit;
required_list_attribute : string -> string list;
required_string_attribute : string -> string;
reset_attribute : string -> unit; root : 'c Pxp_document.node;
set_attribute : ?force:bool -> string -> Pxp_types.att_value -> unit;
set_attributes : (string * Pxp_types.att_value) list -> unit;
set_comment : string option -> unit; set_data : string -> unit;
set_namespace_info : 'c Pxp_document.namespace_info option -> unit;
set_nodes : 'c Pxp_document.node list -> unit;
sub_nodes : 'c Pxp_document.node list; validate : unit -> unit;
validate_attlist : unit -> unit;
validate_contents : ?use_dfa:bool ->
?check_data_nodes:bool -> unit -> unit;
write : ?prefixes:string list ->
?default:string ->
Pxp_types.output_stream -> Pxp_types.encoding -> unit >
Type 'a = 'a Pxp_document.node Pxp_document.extension
is not compatible with type
'c =
< clone : 'c; node : 'c Pxp_document.node;
set_node : 'c Pxp_document.node -> unit; .. >
make: *** [code] Error 2
I am not being able to define PXP objects inside classes. Could you help me solve this problem ?
Thanks
Gaurav
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^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [Caml-list] Pxp objects inside class definition
2002-07-09 8:35 [Caml-list] Pxp objects inside class definition Gaurav Chanda
@ 2002-07-09 12:20 ` Gerd Stolpmann
0 siblings, 0 replies; 2+ messages in thread
From: Gerd Stolpmann @ 2002-07-09 12:20 UTC (permalink / raw)
To: gaurav_chanda; +Cc: caml-list
Gaurav Chanda wrote:
> Hello
>
> I am using the Polymorphic XML Parser (PXP) to parse XML documents. I have made 2 files : point.ml and point.mli, which contain simple class definitions.
>
> The file point.mli contains:
>
> open Pxp_yacc ;
> open Pxp_document ;
> open Pxp_types ;
>
> class type point_sig =
> object
> value mutable x : Pxp_document.node 'a;
> end;
>
> class point : point_sig ;
>
>
> The file point.ml contains:
>
> open Pxp_yacc ;
> open Pxp_document ;
> open Pxp_types ;
>
> class type point_sig =
> object
> value mutable x : Pxp_document.node 'a;
> end ;
>
> value def = "<def></def>" ;
> value def = parse_wfdocument_entity default_config (from_string def) default_spec ;
> value defr = def#root ;
>
> class point:point_sig =
> object
> value mutable x = defr;
> end;
>
> I get an error message while compilation. My compilation command is :
> ocamlopt -pp "camlp4r pa_extend.cmo" -I +camlp4 -I Ty/ -I /usr/lib/ocaml/site-lib/netstring -I /usr/lib/ocaml/site-lib/pxp-engine -I /usr/lib/ocaml/site-lib/pxp-lex-iso88591/ -c point.mli point.ml
>
>
> The error message is :
>
> File "point.ml", line 15, characters 8-67:
> The class type
> object
> val mutable x :
> ('a Pxp_document.node Pxp_document.extension as 'a) Pxp_document.node
> end
> is not matched by the class type point_sig
> The class type
> object
> val mutable x :
> ('a Pxp_document.node Pxp_document.extension as 'a) Pxp_document.node
> end
> is not matched by the class type
> object
> val mutable x :
> ('a Pxp_document.node #Pxp_document.extension as 'a) Pxp_document.node
> end
[...]
>
> I am not being able to define PXP objects inside classes. Could you help me solve this problem ?
Hi Garuav,
(the following in classic syntax)
the problem is that 'a Pxp_document.node is not the full type, because
there is a constraint on the parameter of the class Pxp_document.node,
and the compiler correctly augments the type such that it reads
('a Pxp_document.node #Pxp_document.extension as 'a) Pxp_document.node.
However, defr has the type
('a Pxp_document.node Pxp_document.extension as 'a) Pxp_document.node,
which is not the same. This is all the long error message wants to tell
you.
The solution is quite simple: Use the complete type instead of
'a Pxp_document.node, i.e.
class type point_sig =
object
val mutable x :
('a Pxp_document.node Pxp_document.extension as 'a) Pxp_document.node
end
Sorry that the types of PXP are that complicated.
('a Pxp_document.node Pxp_document.extension as 'a) Pxp_document.node
reflects the fact that nodes have extensions, and the extensions are
recursively bound to their nodes. This is sometimes a bit unhandy.
Gerd
--
------------------------------------------------------------
Gerd Stolpmann * Viktoriastr. 45 * 64293 Darmstadt * Germany
gerd@gerd-stolpmann.de http://www.gerd-stolpmann.de
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