Module Wd_types

module Wd_types: sig .. end

type 'a dict = 'a Wd_dictionary.t 

The type 'a dict is just an abbreviation for dictionaries (mappings from strings to 'a).

Events are generated when the user presses a button, clicks at a hyperlink, or opens a server-generated popup window.

• Button n: The button with name n has been pressed (<ui:button name="n" ...>)
• Image_button (n,x,y): The image button with name n has been pressed at the coordinates (x,y). (<ui:imagebutton name="n" ...>)
• Indexed_button (n,i): The button with name n and index i has been pressed (<ui:button name="n" index="i" ...>)
• Indexed_image_button (n,i,x,y): The image button with name n and index i has been pressed at the coordinates (x,y). (<ui:imagebutton name="n" index="i" ...>)
• No_event: This value indicates that there was no event (or no recognized event)
• Popup_request s: A server popup window has just popped up, and the contents for the window have been requested. The argument is the second argument of the "open" Javascript function that has been generated by the ui:server-popup element.

Values of this type store the mapping from the (name,index) pairs of interactor elements to the real CGI parameter names together with auxiliary components.

What's the problem? Interactor elements like ui:a allow the programmer to identify these either by a single name (which is an arbitrary string) or by a pair of a "name" and an "index" (i.e. two arbitrary strings). In contrast to this, CGI parameter names are much more restricted. First, these names are only strings; there is no built-in representation for pairs of strings. Second, you cannot use arbitrary characters within these names because of limitations of the transport protocol and because of bugs in browsers. (As the "multipart/form-data" representation used in the transport protocol bases on the RFC 822 mail format, it is neither possible to pass 8 bit values, nor to pass control characters. A known bug in Netscape browsers is that the double-quote and backslash characters are incorrectly represented.)

The solution is to generate the CGI parameter names using only unproblematic characters, and to keep the mapping of the original string or string * string to the generated CGI name. This record stores the mappings for the various namespaces. The mapping is encapsulated in the Wd_interactor module, and the type 'a Wd_interactor.t (where 'a is arbitrary) represents such a mapping. The CGI names are simply enumerated, and the Wd_interactor.t value stores only the numbers (IDs) of the CGI parameters. The complete CGI name is formed using a prefix and the number stored in Wd_interactor.t. For example, ui:buttons without index have the prefix "button_"; and if the ui_button record component contains entries for the IDs 0, 1, and 2, the complete CGI names are "button_0", "button_1", and "button_2", respectively.

The type parameter 'a of 'a Wd_interactor.t is the type of the auxiliary component stored with every entry. See below for the meanings in every case.

The Wd_interactor.t structure always maps from pairs string * string to numeric IDs. Because of this, there are usually two mappings, one for the (name,index) pairs, and one for the simple names. The record components listed below that have a name with "indexed" are responsible for the pairs, the corresponding component without "indexed" stores the mapping for the simple case.

The simple case is represented as Wd_interactor.t by using always the empty string "" as index.

THE COMPONENTS ARE:

1. BUTTON-TYPE INTERACTORS:
   • ui_buttons: Enumerates the ui:button interactors that have only a name, not an index. CGI prefix: "button_".
   • ui_indexed_buttons: Enumerates the ui:button interactors that have both a name and an index. CGI prefix: "xbutton_".
   • ui_imagebuttons: Enumerates the ui:imagebutton interactors that have only a name, not an index. CGI prefix: "imagebutton_".
   • ui_indexed_imagebuttons: Enumerates the ui:imagebutton interactors that have both a name and an index. CGI prefix: "ximagebutton_".
   • ui_anchors: Enumerates the ui:a interactors that have only a name, not an index. CGI prefix: "anchor_".
   • ui_indexed_anchors: Enumerates the ui:a interactors that have both a name and an index. CGI prefix: "xanchor_".

   These components use the auxiliary component to store the "goto" attribute of the interactor, if present.

2. BOX-LIKE INTERACTORS:
   • ui_vars: Enumerates the interactors that are bound to an object variable (i.e. they have a variable attribute, like ui:text). As variables allow either only non-indexed names or only indexed names, this component contains both interactors identified by a simple string name and interactors identified by (name,index) pairs; it is not possible that there are conflicts between the two naming methods. CGI prefix: "var_". This component does not have an auxiliary component.
   • ui_enumvars: This list enumerates the simple names (name, None, pg) or pairs (name, Some index, pg) that occur in checkbox, radiobutton and select list interactors. pg is the name of the page where the interactor occurs (knowing the page is necessary for popup dialogues).
   • ui_uploads: Enumerates the ui:file interactors. These may only have a simple name. CGI prefix: "upload_". This component does not have an auxiliary component.

poly_var_value is the type of instance variables of dialogs. There are six possibilities for poly_var_values:

• String_value s: The instance variable contains the string s
• Enum_value [x1;x2;...]: The instance variable contains an enumerator value with the internal items x1, x2, etc. (As variables are declared it is known which items are possible, and whether there are corresponding external values.)
• Dialog_value None: The instance variable does not contain a dialog.
• Dialog_value (Some dlg): The variable contains the dialog dlg.
• Dyn_enum_value [(x1,y1);(x2,y2);...]: The variable contains the enumerator with internal items x1, x2,... and the corresponding external values y1, y2, ...
• Alist_value [(i1,v1); (i2,v2); ...]: The variable contains the associative list where the index i1 is mapped to the value v1, i2 is mapped to v2 etc.

See also Wd_types.var_value below.

The type of an enumeration declaration (i.e. ui:enumeration). The component enum_name is the name of the enumeration. The component enum_definition is the list of the pairs of internal and external names, in the right order.

The different variable types

This record describes variable declarations. var_name contains the name of the variable. var_type is the declared type according to the type attribute. var_default contains either None, in which case no special initial value is declared, or Some v, where v is the initial value. var_temporary corresponds to the temporary attribute, var_associative to the associative attribute, and finally var_protected to the protected attribute.

This record contains the CGI header of the response. It is initialized quite early and can be modified while executing the request. The fields correspond to the arguments of the method set_header of the class type cgi_activation, defined in Netcgi_types.

type debug_mode_style = [ `Fully_encoded | `Partially_encoded ] 

Whether the generated HTML comments do escape HTML meta characters always (`Fully_encoded), or only partially (`Partially_encoded).

This record contains data that may be different for every CGI request. The debug_mode and prototype_mode components are true iff the corresponding mode is switched on. The server_popup_mode is true iff the current request is a popup request. self_url is the URL that invokes the CGI recursively. cgi contains the full CGI request. The request_header is the designated header of the HTTP response.

This record is private for the transformation engine.

type ('a, 'b, 'c) poly_ds_buf = ('a, 'b, 'c) Wd_serialize_types.poly_ds_buf = {

The deserialization buffer

class type dialog_decl_type = object .. end

This class type contains the dialog declaration

class type virtual dialog_type = object .. end

This class contains the dialog instance

class type application_type = object .. end

This class represents the whole application

class type template_type = object .. end

This class represents a template definition

class type syntax_tree_type = object .. end

This class represents the XML syntax tree

class type universe_type = object .. end

The universe is the registry of classes and dialogs

class type session_manager_type = object .. end

The session manager creates new sessions, and looks sessions up in the (possibly fictive) session database

class type session_type = object .. end

This is a single session

type var_value = dialog_type poly_var_value 

This type is the concrete version of Wd_types.poly_var_value that is actually used

type var_decl = dialog_type poly_var_decl 

This type is the concrete version of Wd_types.poly_var_decl that is actually used

type ds_buf = (universe_type, dialog_type, environment)
       poly_ds_buf 

This type is the concrete version of Wd_serialize.poly_ds_buf that is actually used

exception Change_dialog of dialog_type

The implementation of the handle method of a dialog may raise Change_dialog to drop the current dialog and continue with another dialog.

exception Change_page of string

The implementation of the handle method of a dialog may raise Change_page to set the next page to display for the current dialog.

exception Formal_user_error of string

A formal error that happens independently of the current runtime state. The string argument explains the error.

exception Runtime_error of string

A certain operation cannot be performed because the current state does not fulfill the necessary preconditions. The string argument explains the error.

exception No_such_variable of string

It has been tried to access a non-declared variable. The string is the name of the variable.

exception Instantiation_error of string

An error generated by the instantiate method. The caller should catch this exception and report the error from its own view