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| <HTML> |
| <HEAD> |
| <TITLE>Ada95 Binding for ncurses</Title> |
| </HEAD> |
| <BODY> |
| <H1>Ada95 Binding for ncurses</H1> |
| by Jürgen Pfeifer. |
| |
| <HR SIZE=3 NOSHADE> |
| <H2>General Remarks</H2> |
| <UL> |
| <LI>This document describes Version 01.00 of the binding.</LI> |
| <LI>The functionality is modeled to be compatible with the ncurses |
| package, a clone of the SVr4 curses model.<BR> |
| I did the development on an Intel box running the latest stable release of |
| <A HREF="http://www.linux.org">Linux</A>, ncurses and the most recent released |
| <A HREF="http://www.gnat.com">GNU Ada Translator</A> |
| gnat versions. For any older versions of ncurses and gnat |
| it is not guaranteed to work.</LI> |
| <LI>You must have the m4 macroprocessor to build this package. |
| If you don't have this program, you can get the FSF version |
| <A HREF="ftp://ftp.gnu.org/pub/gnu/">here</A>.</LI> |
| <LI>Ada programs are supposed to be readable. One of my |
| favorite methods to make code readable is to use expressive |
| names for the identifiers. You can find a list of a mapping |
| of the cryptic curses names to the Ada names in this <A HREF="ada/table.html">table</A>.</LI> |
| <LI>This is not a typical one-to-one interface mapping. It is |
| close to one-to-one on the functional level. Each (n)curses function |
| has it's counterpart with a more or less similar formal parameter list |
| in the binding. It is not one-to-one with respect to the datatypes. |
| I tried to make records out of the flat chtype and similar structures, |
| so you don't have to do bit operations to mark an attributed character |
| as bold. Just make the boolean member <STRONG>bold</STRONG> of the record |
| true. The binding also hides the structures like WINDOW, PANEL, MENU, FORM |
| etc. ! It's a pure functional API.</LI> |
| <LI>I try to do as much error checking as possible and feasible |
| in the binding. I will raise an Ada exception when something |
| went wrong in the low-level curses. This has the effect that - at least |
| first time in my life - (n)curses programs have now a very rigid error |
| checking, but - thanks to Ada - you don't have to code the orgiastic |
| error checking style of C.</LI> |
| <LI>Support for wide characters is currently not in the binding, as it |
| is not really in ncurses at this point in time.</LI> |
| </UL> |
| |
| <H2>Limitations</H2> |
| <UL> |
| <LI>I provide no SCREEN datatype and functions to set a new screen. |
| If you need this (mostly for debugging I guess), write a small |
| C routine doing all this and import it into your Ada program.</LI> |
| <LI>I provide no functions to switch on/off curses tracing options. |
| Same suggestion as above.</LI> |
| <LI>Although Ada95 is an OO Language, this binding doesn't provide |
| an OO abstraction of the (n)curses functionality. As mentioned above |
| it's a thin binding for the (n)curses functions. But without any |
| doubt it would be nice to build on top of this an OO abstraction |
| of (n)curses functionality.<BR> |
| The only exception is the method how fieldtypes are represented in |
| this Binding. We provide an abstract tagged type Field_Type from |
| which the various fieldtypes are derived.</LI> |
| <LI>I currently do not support the link_fieldtype functionality of the |
| forms subsystem.</LI> |
| <LI>The *_IO packages are currently output only.</LI> |
| </UL> |
| |
| <H2>Hierarchy of packages</H2> |
| <UL> |
| <LI><A HREF="ada/terminal_interface__ads.htm">Terminal_Interface</A> |
| <UL><LI><A HREF="ada/terminal_interface-curses__ads.htm">Curses</A> |
| <UL><LI><A HREF="ada/terminal_interface-curses-mouse__ads.htm">Mouse</A> |
| <LI><A HREF="ada/terminal_interface-curses-panels__ads.htm">Panels</A> |
| <UL><LI><A HREF="ada/terminal_interface-curses-panels-user_data__ads.htm">User_Data</A> |
| </UL> |
| <LI><A HREF="ada/terminal_interface-curses-menus__ads.htm">Menus</A> |
| <UL><LI><A HREF="ada/terminal_interface-curses-menus-menu_user_data__ads.htm">Menu_User_Data</A> |
| <LI><A HREF="ada/terminal_interface-curses-menus-item_user_data__ads.htm">Item_User_Data</A> |
| </UL> |
| <LI><A HREF="ada/terminal_interface-curses-forms__ads.htm">Forms</A> |
| <UL><LI><A HREF="ada/terminal_interface-curses-forms-form_user_data__ads.htm">Form_User_Data</A> |
| <LI><A HREF="ada/terminal_interface-curses-forms-field_user_data__ads.htm">Field_User_Data</A> |
| <LI><A HREF="ada/terminal_interface-curses-forms-field_types__ads.htm">Field_Types</A> |
| <UL><LI><A HREF="ada/terminal_interface-curses-forms-field_types-alpha__ads.htm">Alpha</A> |
| <LI><A HREF="ada/terminal_interface-curses-forms-field_types-alphanumeric__ads.htm">AlphaNumeric</A> |
| <LI><A HREF="ada/terminal_interface-curses-forms-field_types-intfield__ads.htm">IntField</A> |
| <LI><A HREF="ada/terminal_interface-curses-forms-field_types-numeric__ads.htm">Numeric</A> |
| <LI><A HREF="ada/terminal_interface-curses-forms-field_types-regexp__ads.htm">RegExp</A> |
| <LI><A HREF="ada/terminal_interface-curses-forms-field_types-ipv4_address__ads.htm">IPV4_Address</A> |
| <LI><A HREF="ada/terminal_interface-curses-forms-field_types-enumeration__ads.htm">Enumeration</A> |
| <UL><LI><A HREF="ada/terminal_interface-curses-forms-field_types-enumeration-ada__ads.htm">Ada</A> |
| </UL> |
| <LI><A HREF="ada/terminal_interface-curses-forms-field_types-user__ads.htm">User</A> |
| <UL><LI><A HREF="ada/terminal_interface-curses-forms-field_types-user-choice__ads.htm">Choice</A> |
| </UL> |
| </UL> |
| </UL> |
| <LI><A HREF="ada/terminal_interface-curses-text_io__ads.htm">Text_IO</A> |
| <UL><LI><A HREF="ada/terminal_interface-curses-text_io-integer_io__ads.htm">Integer_IO</A> |
| <LI><A HREF="ada/terminal_interface-curses-text_io-float_io__ads.htm">Float_IO</A> |
| <LI><A HREF="ada/terminal_interface-curses-text_io-fixed_io__ads.htm">Fixed_IO</A> |
| <LI><A HREF="ada/terminal_interface-curses-text_io-decimal_io__ads.htm">Decimal_IO</A> |
| <LI><A HREF="ada/terminal_interface-curses-text_io-modular_io__ads.htm">Modular_IO</A> |
| <LI><A HREF="ada/terminal_interface-curses-text_io-enumeration_io__ads.htm">Enumeration_IO</A> |
| <LI><A HREF="ada/terminal_interface-curses-text_io-complex_io__ads.htm">Complex_IO</A> |
| </UL> |
| </UL> |
| </UL> |
| </UL> |
| If you want to navigate through the html pages of the package specs, click <A HREF="ada/index.htm">here</A>. |
| <H2>Implementation Details</H2> |
| <H4>Behind the abstraction</H4> |
| All the new types like <STRONG>Window</STRONG>, <STRONG>Panel</STRONG>, |
| <STRONG>Menu</STRONG>, <STRONG>Form</STRONG> etc. are just |
| opaque representations of the pointers to the corresponding |
| low level (n)curses structures like |
| <STRONG>WINDOW *</STRONG>, <STRONG>PANEL *</STRONG>, |
| <STRONG>MENU *</STRONG> or <STRONG>FORM *</STRONG>. |
| So you can safely pass them to C routines that expect a pointer |
| to one of those structures. |
| <H4>Extended ripoffline() usage</H4> |
| The official documentation of (n)curses says, that the line parameter |
| determines only whether or not exactly <STRONG>one</STRONG> line is |
| stolen from the top or bottom of the screen. So essentially only the |
| sign of the parameter is evaluated. ncurses has internally implemented |
| it in a way, that uses the line parameter also to control the amount of |
| lines to steal. This mechanism is used in the <STRONG>Rip_Off_Lines</STRONG> |
| routine of the binding. |
| <H4><A NAME="userpointer">How user defined field types work</A></H4> |
| TBD |
| <H4>Enumeration fields handling</H4> |
| The (n)curses documentation says, that the String arrays to be passed to |
| an TYPE_ENUM fieldtype must not be automatic variables. This is not true |
| in this binding, because it is internally arranged to safely copy these |
| values. |
| <H4><A NAME="compiler">Using other Ada compilers</A></H4> |
| This should basically not be a problem. |
| <H4>Port to other curses implementations</H4> |
| Basically it should not be too hard to make all this run on a regular SVr4 |
| implementation of curses. The problems are probably these:<BR> |
| <UL> |
| <LI>ncurses has some additional features which are presented in this binding. You |
| have two choices to deal with this: |
| <UL> |
| <LI>Emulate the feature in this binding</LI> |
| <LI>Raise an exception for non implemented features</LI> |
| </UL> |
| Most likely you will follow a mixed approach. Some features are easy to simulate, |
| others will be hard if not impossible.</LI> |
| </UL> |
| I'm quite sure I forgot something. |
| </BODY> |
| </HTML> |
