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33<HTML>
34<HEAD>
35<TITLE>Ada95 Binding for ncurses</Title>
36</HEAD>
37<BODY>
38<H1>Ada95 Binding for ncurses</H1>
39by J&uuml;rgen Pfeifer.
40
41<HR SIZE=3 NOSHADE>
42<H2>General Remarks</H2>
43<UL>
44<LI>This document describes Version 01.00 of the binding.</LI>
45<LI>The functionality is modeled to be compatible with the ncurses
46package, a clone of the SVr4 curses model.<BR>
47I did the development on an Intel box running the latest stable release of
48<A HREF="http://www.linux.org">Linux</A>, ncurses and the most recent released
49<A HREF="http://www.gnat.com">GNU Ada Translator</A>
50gnat versions. For any older versions of ncurses and gnat
51it is not guaranteed to work.</LI>
52<LI>You must have the m4 macroprocessor to build this package.
53If you don't have this program, you can get the FSF version
54<A HREF="ftp://ftp.gnu.org/pub/gnu/">here</A>.</LI>
55<LI>Ada programs are supposed to be readable. One of my
56favorite methods to make code readable is to use expressive
57names for the identifiers. You can find a list of a mapping
58of the cryptic curses names to the Ada names in this <A HREF="ada/table.html">table</A>.</LI>
59<LI>This is not a typical one-to-one interface mapping. It is
60close to one-to-one on the functional level. Each (n)curses function
61has it's counterpart with a more or less similar formal parameter list
62in the binding. It is not one-to-one with respect to the datatypes.
63I tried to make records out of the flat chtype and similar structures,
64so you don't have to do bit operations to mark an attributed character
65as bold. Just make the boolean member <STRONG>bold</STRONG> of the record
66true. The binding also hides the structures like WINDOW, PANEL, MENU, FORM
67etc. ! It's a pure functional API.</LI>
68<LI>I try to do as much error checking as possible and feasible
69in the binding. I will raise an Ada exception when something
70went wrong in the low-level curses. This has the effect that - at least
71first time in my life - (n)curses programs have now a very rigid error
72checking, but - thanks to Ada - you don't have to code the orgiastic
73error checking style of C.</LI>
74<LI>Support for wide characters is currently not in the binding, as it
75is not really in ncurses at this point in time.</LI>
76</UL>
77
78<H2>Limitations</H2>
79<UL>
80<LI>I provide no SCREEN datatype and functions to set a new screen.
81If you need this (mostly for debugging I guess), write a small
82C routine doing all this and import it into your Ada program.</LI>
83<LI>I provide no functions to switch on/off curses tracing options.
84Same suggestion as above.</LI>
85<LI>Although Ada95 is an OO Language, this binding doesn't provide
86an OO abstraction of the (n)curses functionality. As mentioned above
87it's a thin binding for the (n)curses functions. But without any
88doubt it would be nice to build on top of this an OO abstraction
89of (n)curses functionality.<BR>
90The only exception is the method how fieldtypes are represented in
91this Binding. We provide an abstract tagged type Field_Type from
92which the various fieldtypes are derived.</LI>
93<LI>I currently do not support the link_fieldtype functionality of the
94forms subsystem.</LI>
95<LI>The *_IO packages are currently output only.</LI>
96</UL>
97
98<H2>Hierarchy of packages</H2>
99<UL>
100<LI><A HREF="ada/terminal_interface__ads.htm">Terminal_Interface</A>
101 <UL><LI><A HREF="ada/terminal_interface-curses__ads.htm">Curses</A>
102 <UL><LI><A HREF="ada/terminal_interface-curses-mouse__ads.htm">Mouse</A>
103 <LI><A HREF="ada/terminal_interface-curses-panels__ads.htm">Panels</A>
104 <UL><LI><A HREF="ada/terminal_interface-curses-panels-user_data__ads.htm">User_Data</A>
105 </UL>
106 <LI><A HREF="ada/terminal_interface-curses-menus__ads.htm">Menus</A>
107 <UL><LI><A HREF="ada/terminal_interface-curses-menus-menu_user_data__ads.htm">Menu_User_Data</A>
108 <LI><A HREF="ada/terminal_interface-curses-menus-item_user_data__ads.htm">Item_User_Data</A>
109 </UL>
110 <LI><A HREF="ada/terminal_interface-curses-forms__ads.htm">Forms</A>
111 <UL><LI><A HREF="ada/terminal_interface-curses-forms-form_user_data__ads.htm">Form_User_Data</A>
112 <LI><A HREF="ada/terminal_interface-curses-forms-field_user_data__ads.htm">Field_User_Data</A>
113 <LI><A HREF="ada/terminal_interface-curses-forms-field_types__ads.htm">Field_Types</A>
114 <UL><LI><A HREF="ada/terminal_interface-curses-forms-field_types-alpha__ads.htm">Alpha</A>
115 <LI><A HREF="ada/terminal_interface-curses-forms-field_types-alphanumeric__ads.htm">AlphaNumeric</A>
116 <LI><A HREF="ada/terminal_interface-curses-forms-field_types-intfield__ads.htm">IntField</A>
117 <LI><A HREF="ada/terminal_interface-curses-forms-field_types-numeric__ads.htm">Numeric</A>
118 <LI><A HREF="ada/terminal_interface-curses-forms-field_types-regexp__ads.htm">RegExp</A>
119 <LI><A HREF="ada/terminal_interface-curses-forms-field_types-ipv4_address__ads.htm">IPV4_Address</A>
120 <LI><A HREF="ada/terminal_interface-curses-forms-field_types-enumeration__ads.htm">Enumeration</A>
121 <UL><LI><A HREF="ada/terminal_interface-curses-forms-field_types-enumeration-ada__ads.htm">Ada</A>
122 </UL>
123 <LI><A HREF="ada/terminal_interface-curses-forms-field_types-user__ads.htm">User</A>
124 <UL><LI><A HREF="ada/terminal_interface-curses-forms-field_types-user-choice__ads.htm">Choice</A>
125 </UL>
126 </UL>
127 </UL>
128 <LI><A HREF="ada/terminal_interface-curses-text_io__ads.htm">Text_IO</A>
129 <UL><LI><A HREF="ada/terminal_interface-curses-text_io-integer_io__ads.htm">Integer_IO</A>
130 <LI><A HREF="ada/terminal_interface-curses-text_io-float_io__ads.htm">Float_IO</A>
131 <LI><A HREF="ada/terminal_interface-curses-text_io-fixed_io__ads.htm">Fixed_IO</A>
132 <LI><A HREF="ada/terminal_interface-curses-text_io-decimal_io__ads.htm">Decimal_IO</A>
133 <LI><A HREF="ada/terminal_interface-curses-text_io-modular_io__ads.htm">Modular_IO</A>
134 <LI><A HREF="ada/terminal_interface-curses-text_io-enumeration_io__ads.htm">Enumeration_IO</A>
135 <LI><A HREF="ada/terminal_interface-curses-text_io-complex_io__ads.htm">Complex_IO</A>
136 </UL>
137 </UL>
138 </UL>
139</UL>
140If you want to navigate through the html pages of the package specs, click <A HREF="ada/index.htm">here</A>.
141<H2>Implementation Details</H2>
142<H4>Behind the abstraction</H4>
143All the new types like <STRONG>Window</STRONG>, <STRONG>Panel</STRONG>,
144<STRONG>Menu</STRONG>, <STRONG>Form</STRONG> etc. are just
145opaque representations of the pointers to the corresponding
146low level (n)curses structures like
147<STRONG>WINDOW *</STRONG>, <STRONG>PANEL *</STRONG>,
148<STRONG>MENU *</STRONG> or <STRONG>FORM *</STRONG>.
149So you can safely pass them to C routines that expect a pointer
150to one of those structures.
151<H4>Extended ripoffline() usage</H4>
152The official documentation of (n)curses says, that the line parameter
153determines only whether or not exactly <STRONG>one</STRONG> line is
154stolen from the top or bottom of the screen. So essentially only the
155sign of the parameter is evaluated. ncurses has internally implemented
156it in a way, that uses the line parameter also to control the amount of
157lines to steal. This mechanism is used in the <STRONG>Rip_Off_Lines</STRONG>
158routine of the binding.
159<H4><A NAME="userpointer">How user defined field types work</A></H4>
160TBD
161<H4>Enumeration fields handling</H4>
162The (n)curses documentation says, that the String arrays to be passed to
163an TYPE_ENUM fieldtype must not be automatic variables. This is not true
164in this binding, because it is internally arranged to safely copy these
165values.
166<H4><A NAME="compiler">Using other Ada compilers</A></H4>
167This should basically not be a problem.
168<H4>Port to other curses implementations</H4>
169Basically it should not be too hard to make all this run on a regular SVr4
170implementation of curses. The problems are probably these:<BR>
171<UL>
172<LI>ncurses has some additional features which are presented in this binding. You
173have two choices to deal with this:
174<UL>
175<LI>Emulate the feature in this binding</LI>
176<LI>Raise an exception for non implemented features</LI>
177</UL>
178Most likely you will follow a mixed approach. Some features are easy to simulate,
179others will be hard if not impossible.</LI>
180</UL>
181I'm quite sure I forgot something.
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