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Steve Kondikae271bc2015-11-15 02:50:53 +0100[diff] [blame]39 <title>Ada95 Binding for ncurses</title>
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46 <h1>Ada95 Binding for ncurses</h1>
47
48 <p>by J&uuml;rgen Pfeifer.</p>
49 <hr>
50
51 <h2>General Remarks</h2>
52
53 <ul>
54 <li>This document describes Version 01.00 of the binding.</li>
55
56 <li>The functionality is modeled to be compatible with the
57 ncurses package, a clone of the SVr4 curses model.<br>
58 I did the development on an Intel box running the latest stable
59 release of <a href="http://www.linux.org">Linux</a>, ncurses
micky3879b9f5e72025-07-08 18:04:53 -0400[diff] [blame]60 and the most recent released <a href="https://ftp.gnu.org/gnu/gcc/">GNU
Steve Kondikae271bc2015-11-15 02:50:53 +0100[diff] [blame]61 Ada Translator</a> gnat versions. For any older versions of
62 ncurses and gnat it is not guaranteed to work.</li>
63
64 <li>You must have the m4 macroprocessor to build this package.
65 If you don't have this program, you can get the FSF version
micky3879b9f5e72025-07-08 18:04:53 -0400[diff] [blame]66 <a href="https://ftp.gnu.org/pub/gnu/">here</a>.</li>
Steve Kondikae271bc2015-11-15 02:50:53 +0100[diff] [blame]67
68 <li>Ada programs are supposed to be readable. One of my
69 favorite methods to make code readable is to use expressive
70 names for the identifiers. You can find a list of a mapping of
71 the cryptic curses names to the Ada names in this <a href=
72 "ada/table.html">table</a>.</li>
73
74 <li>This is not a typical one-to-one interface mapping. It is
75 close to one-to-one on the functional level. Each (n)curses
micky3879b9f5e72025-07-08 18:04:53 -0400[diff] [blame]76 function has its counterpart with a more or less similar
Steve Kondikae271bc2015-11-15 02:50:53 +0100[diff] [blame]77 formal parameter list in the binding. It is not one-to-one with
78 respect to the datatypes. I tried to make records out of the
79 flat chtype and similar structures, so you don't have to do bit
80 operations to mark an attributed character as bold. Just make
81 the boolean member <strong>bold</strong> of the record true.
82 The binding also hides the structures like WINDOW, PANEL, MENU,
micky3879b9f5e72025-07-08 18:04:53 -0400[diff] [blame]83 FORM etc. ! It is a pure functional API.</li>
Steve Kondikae271bc2015-11-15 02:50:53 +0100[diff] [blame]84
85 <li>I try to do as much error checking as possible and feasible
86 in the binding. I will raise an Ada exception when something
87 went wrong in the low-level curses. This has the effect that -
88 at least first time in my life - (n)curses programs have now a
89 very rigid error checking, but - thanks to Ada - you don't have
90 to code the orgiastic error checking style of C.</li>
91
92 <li>Support for wide characters is currently not in the
93 binding, as it is not really in ncurses at this point in
94 time.</li>
95 </ul>
96
97 <h2>Limitations</h2>
98
99 <ul>
100 <li>I provide no SCREEN datatype and functions to set a new
101 screen. If you need this (mostly for debugging I guess), write
102 a small C routine doing all this and import it into your Ada
103 program.</li>
104
105 <li>I provide no functions to switch on/off curses tracing
106 options. Same suggestion as above.</li>
107
108 <li>Although Ada95 is an OO Language, this binding doesn't
109 provide an OO abstraction of the (n)curses functionality. As
micky3879b9f5e72025-07-08 18:04:53 -0400[diff] [blame]110 mentioned above it is a thin binding for the (n)curses
Steve Kondikae271bc2015-11-15 02:50:53 +0100[diff] [blame]111 functions. But without any doubt it would be nice to build on
112 top of this an OO abstraction of (n)curses functionality.<br>
113 The only exception is the method how fieldtypes are represented
114 in this Binding. We provide an abstract tagged type Field_Type
115 from which the various fieldtypes are derived.</li>
116
117 <li>I currently do not support the link_fieldtype functionality
118 of the forms subsystem.</li>
119
120 <li>The *_IO packages are currently output only.</li>
121 </ul>
122
123 <h2>Hierarchy of packages</h2>
124
125 <ul>
126 <li>
127 <a href=
128 "ada/terminal_interface__ads.htm">Terminal_Interface</a>
129
130 <ul>
131 <li>
132 <a href=
133 "ada/terminal_interface-curses__ads.htm">Curses</a>
134
135 <ul>
136 <li><a href=
137 "ada/terminal_interface-curses-mouse__ads.htm">Mouse</a></li>
138
139 <li>
140 <a href=
141 "ada/terminal_interface-curses-panels__ads.htm">Panels</a>
142
143 <ul>
144 <li><a href=
145 "ada/terminal_interface-curses-panels-user_data__ads.htm">
146 User_Data</a></li>
147 </ul>
148 </li>
149
150 <li>
151 <a href=
152 "ada/terminal_interface-curses-menus__ads.htm">Menus</a>
153
154 <ul>
155 <li><a href=
156 "ada/terminal_interface-curses-menus-menu_user_data__ads.htm">
157 Menu_User_Data</a></li>
158
159 <li><a href=
160 "ada/terminal_interface-curses-menus-item_user_data__ads.htm">
161 Item_User_Data</a></li>
162 </ul>
163 </li>
164
165 <li>
166 <a href=
167 "ada/terminal_interface-curses-forms__ads.htm">Forms</a>
168
169 <ul>
170 <li><a href=
171 "ada/terminal_interface-curses-forms-form_user_data__ads.htm">
172 Form_User_Data</a></li>
173
174 <li><a href=
175 "ada/terminal_interface-curses-forms-field_user_data__ads.htm">
176 Field_User_Data</a></li>
177
178 <li>
179 <a href=
180 "ada/terminal_interface-curses-forms-field_types__ads.htm">
181 Field_Types</a>
182
183 <ul>
184 <li><a href=
185 "ada/terminal_interface-curses-forms-field_types-alpha__ads.htm">
186 Alpha</a></li>
187
188 <li><a href=
189 "ada/terminal_interface-curses-forms-field_types-alphanumeric__ads.htm">
190 AlphaNumeric</a></li>
191
192 <li><a href=
193 "ada/terminal_interface-curses-forms-field_types-intfield__ads.htm">
194 IntField</a></li>
195
196 <li><a href=
197 "ada/terminal_interface-curses-forms-field_types-numeric__ads.htm">
198 Numeric</a></li>
199
200 <li><a href=
201 "ada/terminal_interface-curses-forms-field_types-regexp__ads.htm">
202 RegExp</a></li>
203
204 <li><a href=
205 "ada/terminal_interface-curses-forms-field_types-ipv4_address__ads.htm">
206 IPV4_Address</a></li>
207
208 <li>
209 <a href=
210 "ada/terminal_interface-curses-forms-field_types-enumeration__ads.htm">
211 Enumeration</a>
212
213 <ul>
214 <li><a href=
215 "ada/terminal_interface-curses-forms-field_types-enumeration-ada__ads.htm">
216 Ada</a></li>
217 </ul>
218 </li>
219
220 <li>
221 <a href=
222 "ada/terminal_interface-curses-forms-field_types-user__ads.htm">
223 User</a>
224
225 <ul>
226 <li><a href=
227 "ada/terminal_interface-curses-forms-field_types-user-choice__ads.htm">
228 Choice</a></li>
229 </ul>
230 </li>
231 </ul>
232 </li>
233 </ul>
234 </li>
235
236 <li>
237 <a href=
238 "ada/terminal_interface-curses-text_io__ads.htm">Text_IO</a>
239
240 <ul>
241 <li><a href=
242 "ada/terminal_interface-curses-text_io-integer_io__ads.htm">
243 Integer_IO</a></li>
244
245 <li><a href=
246 "ada/terminal_interface-curses-text_io-float_io__ads.htm">
247 Float_IO</a></li>
248
249 <li><a href=
250 "ada/terminal_interface-curses-text_io-fixed_io__ads.htm">
251 Fixed_IO</a></li>
252
253 <li><a href=
254 "ada/terminal_interface-curses-text_io-decimal_io__ads.htm">
255 Decimal_IO</a></li>
256
257 <li><a href=
258 "ada/terminal_interface-curses-text_io-modular_io__ads.htm">
259 Modular_IO</a></li>
260
261 <li><a href=
262 "ada/terminal_interface-curses-text_io-enumeration_io__ads.htm">
263 Enumeration_IO</a></li>
264
265 <li><a href=
266 "ada/terminal_interface-curses-text_io-complex_io__ads.htm">
267 Complex_IO</a></li>
268 </ul>
269 </li>
270 </ul>
271 </li>
272 </ul>
273 </li>
274 </ul>
275
276 <p>If you want to navigate through the html pages of the package
277 specs, click <a href="ada/index.htm">here</a>.</p>
278
279 <h2>Implementation Details</h2>
280
281 <h4>Behind the abstraction</h4>
282
283 <p>All the new types like <strong>Window</strong>,
284 <strong>Panel</strong>, <strong>Menu</strong>,
285 <strong>Form</strong> etc. are just opaque representations of the
286 pointers to the corresponding low level (n)curses structures like
287 <strong>WINDOW *</strong>, <strong>PANEL *</strong>, <strong>MENU
288 *</strong> or <strong>FORM *</strong>. So you can safely pass
289 them to C routines that expect a pointer to one of those
290 structures.</p>
291
292 <h4>Extended ripoffline() usage</h4>
293
294 <p>The official documentation of (n)curses says, that the line
295 parameter determines only whether or not exactly
296 <strong>one</strong> line is stolen from the top or bottom of the
297 screen. So essentially only the sign of the parameter is
298 evaluated. ncurses has internally implemented it in a way, that
299 uses the line parameter also to control the amount of lines to
300 steal. This mechanism is used in the
301 <strong>Rip_Off_Lines</strong> routine of the binding.</p>
302
303 <h4><a name="userpointer" id="userpointer">How user defined field
304 types work</a></h4>
305
306 <p>TBD</p>
307
308 <h4>Enumeration fields handling</h4>
309
310 <p>The (n)curses documentation says, that the String arrays to be
311 passed to an TYPE_ENUM fieldtype must not be automatic variables.
312 This is not true in this binding, because it is internally
313 arranged to safely copy these values.</p>
314
315 <h4><a name="compiler" id="compiler">Using other Ada
316 compilers</a></h4>
317
318 <p>This should basically not be a problem.</p>
319
320 <h4>Port to other curses implementations</h4>
321
322 <p>Basically it should not be too hard to make all this run on a
323 regular SVr4 implementation of curses. The problems are probably
324 these:<br></p>
325
326 <ul>
327 <li>ncurses has some additional features which are presented in
328 this binding. You have two choices to deal with this:
329
330 <ul>
331 <li>Emulate the feature in this binding</li>
332
333 <li>Raise an exception for non implemented features</li>
334 </ul>
335
336 <p>Most likely you will follow a mixed approach. Some
337 features are easy to simulate, others will be hard if not
338 impossible.</p>
339 </li>
340 </ul>
341
342 <p>I'm quite sure I forgot something.</p>
343</body>
344</html>