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(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify this GNU Manual, like GNU software.  Copies published by the Free Software Foundation raise funds for GNU development.''

This document is part of a collection distributed under the GNU Free Documentation License.  If you want to distribute this document separately from the collection, you can do so by adding a copy of the license to the document, as described in section 6 of the license.

Overview
********

The Emacs mode for programming in Ada 95 with GNAT helps the user in understanding existing code and facilitates writing new code.  It furthermore provides some utility functions for easier integration of standard Emacs features when programming in Ada.

General features:
=================

  * full Integrated Development Environment:

       * support of ``project files'' for the configuration (directories, compilation options,...)

       * compiling and stepping through error messages.

       * running and debugging your applications within Emacs.

  * easy to use for beginners by pull-down menus,

  * user configurable by many user-option variables.

Ada mode features that help understanding code:
===============================================

  * functions for easy and quick stepping through Ada code,

  * getting cross reference information for identifiers (e.g. find the defining place by a keystroke),

  * displaying an index menu of types and subprograms and move point to the chosen one,

  * automatic color highlighting of the various entities in Ada code.

Emacs support for writing Ada code:
===================================

  * switching between spec and body files with eventually auto-generation of body files,

  * automatic formating of subprograms parameter lists.

  * automatic smart indentation according to Ada syntax,

  * automatic completion of identifiers,

  * automatic casing of identifiers, keywords, and attributes,

  * insertion of statement templates,

  * filling comment paragraphs like filling normal text,

Installation
************

If you  got Ada mode as  a separate distribution, you  should have a look at the  README file.  It explains the  basic steps necessary for a good installation of the emacs Ada mode.

Installing the  Ada mode  is basically  just a matter  of copying  a few files into  the Emacs  library directories. Every  time you open  a file with  a  file  extension  of  .ads  or  .adb,  Emacs  will automatically load and activate Ada mode.

See Using non-standard file names, if your  files do not use these extensions and if you want Emacs to automatically start the Ada mode every time you edit an Ada file.

See also the Emacs Manual (see (Top (The Emacs Manual))), for general usage variables that you might want to set.

Required files
==============

This Ada  mode works best  with Emacs 20.3  or higher (the  easy editing features for the  project files won't work with  any older version), but most of the commands should work  with older versions too. Please try to install  the  most  recent  version  of  Emacs  on  your  system  before installing Ada mode.

Although part of Ada mode is compiler-independent, the most advanced features are specific to the Gnat compiler http://www.gnat.com.

The following files are provided with the Ada mode distribution:

  * ada-mode.el: The main file for Ada mode. This  is the  only file  which does  not require  Gnat. It  contains the functions  for  indentation,  formatting  of parameter  lists,  stepping through  code, comment  handling and  automatic casing.   Emacs versions 20.2 and higher already contain Ada mode version 2.27, which is an older version of this file  and should be replaced. Loading ada-mode.el from the current distribution supersedes the standard installation.

  * ada-stmt.el: Contains the statement templates feature.

  * ada-xref.el: This file provides the main support for Gnat.
     This  is  where  the   functions  for  cross-references,  completion  of
     identifiers,  support   for  project  files  and   compilation  of  your
     application are defined.

  * ada-prj.el: The functions to use for easy-edition of the project files.  This file is the only one which really requires Emacs at least 20.2. It uses the new widget features from Emacs.

Customizing Ada mode
********************

Ada mode is  fully customizable. Everything, from the  file names to the automatic  indentation and  the automatic casing  can be  adapted to your own needs.

There  are   two  different  kinds   of  variables  that   control  this customization, both are easy to modify.

The first set of variables are standard Emacs variables. Of course, some are defined  only for Ada  mode, whereas others have  a more general meaning  in   Emacs.  Please  see  the  Emacs   documentation  for  more information on the latest. In this documentation, we will detail all the variables that are specific to Ada mode, and a few others. The names will be given, as in ada-case-identifier.

Emacs provides an easy way to modify them, through a special mode called customization.    To    access    this    mode,    select    the    menu Ada->Customize.  This will open a new buffer with some fields that you can edit.  For instance, you will get something like:

     Put below the compiler switches.
     comp_opt= _____________________________________

The first  line gives a brief  description of the  variable.  The second line is  the name of  the variable  and the field  where you can  give a value for this variable. Simply type what you want in the field.

When you are  finished modifying the variables, you  can simply click on the Save for future sessions button  at the top of the buffer (click with  the  middle mouse  button).  This will  save  the  values in  your .emacs file, so that next time you start Emacs they will have the same values.

To modify a specific variable, you can directly call the function customize-variable from Emacs (just type M-x customize-variable RET VARIABLE-NAME RET).

Some users might prefer to modify the variables directly in their configuration file, .emacs. This file is coded in Emacs lisp, and the syntax to set a variable is the following:

     (setq variable-name value)

The second set of variables for customization are set through the use of project files. These variables are  specific to a given project, whereas the  first   set  was  more   general.  For  more   information,  please see Project files.

Project files
*************

General overview
================

Emacs provides a full Integrated Development Environment for GNAT and Ada programmers. That is to say, editing, compiling, executing and debugging can be performed within Emacs in a convenient and natural way.

To take full advantage of this features, it is possible to create a file in  the main  directory of  your application,  with a  .adp extension. This  file contain  all needed  information  dealing with  the way  your application is  organized between directories, the  commands to compile, run and debug it etc. Creating this file is not mandatory and convenient defaults are  automatically provided for simple setups.  It only becomes necessary when those above mentioned defaults need customizing.

A simple way to edit this file is provided for Emacs 20.2 or newer, with the  following functions,  that  you  can access  also  through the  Ada menu. It  is also possible  to edit the  project file as a  regular text file.

Once  in the  buffer for  editing the  project file,  you can  save your modification using  the [OK]  button at the  bottom of the  buffer, or simply   use  the  usual   C-x  C-s   binding.   To   cancel  your modifications, simply kill the buffer  or click on the [CANCEL] button at the button.

Each buffer using Ada mode will be associated with one project file when there  is one  available,  so  that Emacs  can  easily navigate  through related source files for instance.

The exact algorithm to determine which project file should be used is described in the next section, but you can force the project file you want to use by setting one or two variables in your .emacs file.

  * To set up a default project file to use for any directory, anywhere on your system, set the variable ada-prj-default-project-file to the name of that file.

          (set 'ada-prj-default-project-file "/dir1/dir2/file")

  * For finer control, you can set a per-directory project file. This is done through the variable ada-xref-default-prj-file.

            (set 'ada-xref-default-prj-file
                 '(("/dir1/dir2" . "/dir3/file1")
                   ("/dir4/dir5" . "/dir6/file2")))

     Note: This has a higher priority than the first variable, so the first choice is to use this variable settings, and otherwise ada-prj-default-project-file.

C-c u
     Create or edit the project file for the current buffer (ada-customize).

C-c c
     Change the project file associated with the current Ada buffer (ada-change-prj).

C-c d
     Change the  default project  file for the  current directory.  Every new file opened  from this  directory will be  associated with that  file by default.

ada-set-default-project-file
     Set the default  project file to use for *any*  Ada file opened anywhere on your system. This sets this file only for the current Emacs session.

Project file variables
======================

The following variables can be defined in a project file.  They all have a default value, so that small  projects do not need to create a project file.

Some  variables below  can be  referenced  in other  variables, using  a shell-like  notation.   For instance,  if  the variable  comp_cmd contains a sequence like ${comp_opt}, the value of that variable will be substituted.

Here is the list of variables:

src_dir          [default: "./"]
     This is  a list of directories where Ada mode will  look for source files. These directories are used mainly  in two cases, both as a switch for the compiler and for the cross-references.

obj_dir             [default: "./"]
     This is a list of directories where to look for object and library files.  The library files are the .ali files generated by Gnat and that contain cross-reference informations.

comp_opt            [default: ""]
     Creates a  variable which can be  referred to subsequently  by using the ${comp_opt} notation.   This is  intended to store  the default switches given to gnatmake and gcc.

bind_opt=SWITCHES   [default: ""]
     Creates a  variable which can be  referred to subsequently  by using the ${bind_opt} notation.   This is  intended to store  the default switches given to gnatbind.

link_opt=SWITCHES   [default: ""]
     Creates a  variable which can be  referred to subsequently  by using the ${link_opt} notation.   This is  intended to store  the default switches given to gnatlink.

main=EXECUTABLE     [default: ""]
     Specifies the name of the  executable for the application. This variable can be referred to in  the following lines by using the ${main} notation.

cross_prefix=PREFIX [default: ""]
     This variable  should be set if  you are working  in a cross-compilation environment. This is the prefix used in front of the gnatmake commands.

remote_machine=MACHINE [default: ""]
     This is the name of the machine to log into before issuing the compilation command. If this variable is empty, the command will be run on the local machine. This will not work on Windows NT machines, since Ada mode will simply precede the compilation command with a rsh command, unknown on Windows.

comp_cmd=COMMAND    [default: "${cross_prefix}gcc -c -I${src_dir} -g -gnatq"]
     Specifies the command used to compile a single file in the application. The name of the file will be added at the end of this command.

make_cmd=COMMAND    [default: "${cross_prefix}gnatmake ${main} -aI${src_dir} -aO${obj_dir} -g -gnatq -cargs ${comp_opt} -bargs ${bind_opt} -largs ${link_opt}"]'
     Specifies the command used to recompile the whole application.

run_cmd=COMMAND     [default: "${main}"]
     Specifies the command used to run the application.

debug_cmd=COMMAND   [default: "${cross_prefix}gdb ${main}"]
     Specifies the command used to debug the application

Detailed algorithm
==================

This section gives more details on the project file setup and is only of interest for advanced users.

Usually, an Ada file is part  of a larger application, whose sources and objects can be spread over multiple directories. The first time emacs is asked to compile, run or debug an application, or when a cross reference function is  used (goto declaration  for instance), the  following steps are taken:

  * find the appropriate project file, open and parse it. All  the fields  read  in the  project  file are  then  stored by  emacs locally.  Finding the project file requires a few steps:

       - if a file from the same directory was already associated with a project file, use the same one. This is the variable ada-xref-default-prj-file described above.

       - if the variable ada-prj-default-project-file is set, use the project file specified in this variable.

       - if there is a project file whose name is the same as the source file except for the suffix, use this one.

       - if  there's only one project file in the source directory, use that one.

       - if there are more than one project file in the source directory, ask the user.

       - if there are no project files in the source directory use standard default values.

     The first project file that is selected in a given directory becomes the default project file for this directory and is used implicitly for other sources unless specified otherwise by the user.

  * look for the corresponding .ali file in the obj_dir defined in the project  file.  If this file can not be  found, emacs proposes to compile the source using the comp_cmd defined in the project file in order to create the ali file.

  * when cross referencing is requested, the .ali  file is parsed to determine  the  file and  line  of  the  identifier definition.   It  is possible for  the .ali file to be  older than the source  file, in which case it will be recompiled if the variable ada-xref-create-ali is set, otherwise the  reference is searched in the  obsolete ali file with possible inaccurate results.

  * look  for   the file containing the declaration using the source path src_dir defined in the  project file.  Put the cursor at the correct position and display this new cursor.

Syntax highlighting
*******************

Ada mode is made to help you understand the structure of your source files. Some  people like having  colors or different fonts  depending on the  context: commands  should be  displayed differently  than keywords, which should also be different from strings, ...

Emacs is able to display in a different way the following syntactic entities:

  * keywords

  * commands

  * strings

  * gnatprep statements (preprocessor)

  * types (under certain conditions)

  * other words

This  is not  the default  behavior for  Emacs. You  have  to explicitly activate it. This requires that you add a new line in your .emacs file (if this file does not exist, just create it).

     (global-font-lock-mode t)

But  the default colors  might not  be the  ones you  like. Fortunately, there  is  a  very  easy  way  to change  them.  Just  select  the  menu Help->Customize->Specific  Face...  and  press RET.  This will display a buffer will all the ``faces'' (the colors) that Emacs knows about. You can change any of them.

Moving Through Ada Code
***********************

There are several  easy to use commands to stroll  through Ada code. All these functions are available through the Ada menu, and you can also use the following key bindings or the command names:

M-C-e
     Move to the next function/procedure/task, which ever comes next (ada-next-procedure).

M-C-a
     Move to previous function/procedure/task (ada-previous-procedure).

M-x ada-next-package
     Move to next package.

M-x ada-prev-package
     Move to previous package.

C-c C-a
     Move to matching start of end (ada-move-to-start).  If point is at the end of a subprogram, this command jumps to the corresponding begin if the user option ada-move-to-declaration is nil (default), it jumps to the subprogram declaration otherwise.

C-c C-e
     Move point to end of current block (ada-move-to-end).

C-c o
     Switch between corresponding spec and body file (ff-find-other-file).  If the cursor is on a subprogram, switch between declaration and body.

C-c c-d
     Move  from   any  reference  to  its  declaration   and  switch  between declaration  and body  (for  procedures, tasks,  private and  incomplete types).

C-c C-r
     runs the gnatfind command to search for all references to the entity pointed by the cursor (ada-find-references).  Use C-x ` (next-error) to visit each reference (as for compilation errors).

These  functions use  the  information in  the  output of  the Gnat  Ada compiler.   However,   if  your   application  was  compiled   with  the -gnatx  switch, these  functions will  not work,  since  no extra information  is generated by  GNAT. See  GNAT documentation  for further information.

Emacs will  try to  run    Gnat for  you whenever the    cross-reference informations  are     older   than your   source   file   (provided  the ada-xref-create-ali variable is  non-nil).  Gnat  then produces a file with the same name  as the current  Ada file but with the extension changed to .ali. This files are normally used  by the binder, but they will also contain additional cross-referencing information.

Identifier completion
*********************

Overview
========

Emacs and  Ada mode provide  two general ways for  the completion of identifiers. This is  an easy way to type faster: you  just have to type the first few  letters of an identifiers, and then  loop through all the possible completions.

The  first method  is general  for  Emacs. It  will work  both with  Ada buffers, but also in C buffers,  Java buffers, ...  The idea is to parse all the opened buffers for possible completions.

For instance, if the words my_identifier, my_subprogram are the only words starting with my in any of the opened files, then you will have this scenario:

     You type:  myM-/ Emacs inserts:  my_identifier If you press M-/ once again, Emacs replaces my_identifier with my_subprogram. Pressing M-/ once more will bring you back to my_identifier.

This is a very  fast way to do completion, and the  casing of words will also be respected.

The second  method is specific to Ada  buffer, and even to  users of the Gnat compiler. Emacs will search the cross-information found in the .ali files generated by Gnat for possible completions.

The  main advantage  is  that  this completion  is  more accurate:  only existing identifier  will be  suggested, you don't  need to have  a file opened that already contains this identifiers, ...

On the other  hand, this completion is a little  bit slower and requires that you  have compiled your file  at least once since  you created that identifier.

Summary of commands
===================

C-TAB
     Complete accurately current identifier using information in .ali file (ada-complete-identifier).

M-/
     Complete identifier using buffer information (not Ada-specific).

Index Menu of Subprograms
*************************

You  can   display  a  choice  menu   with  all  procedure/function/task declarations in the file and choose an item by mouse click to get to its declaration.  This function is  accessible through  the Ada menu when editing a Ada file, or simply through the following key binding:

C-S-Mouse-3
     display index menu

File Browser
************

Emacs provides a special mode, called speedbar. When this mode is activated, a new frame is displayed, with a file browser. The files from the current  directory are displayed, and  you can click on  them as you would with any file browser. The following commands are then available.

You can click  on a directory name  or file name to open  it. The editor will  automatically  select  the  best  possible  mode  for  this  file, including of course Ada mode for files written in Ada.

If you click on the [+] symbol near a file name, all the symbols (types, variables and subprograms)  defined in that file will  be displayed, and you  can directly click  on them  to open  the right  file at  the right place.

You can activate  this mode by typing M-x  speedbar in the editor. This  will open  a new  frame. A  better way  might be  to  assicate the following key binding

     (global-set-key [f7]  'speedbar-get-focus)

Every time you press F7,  the mouse will automatically move to the speedbar frame (which will be created if it does not exist).

Automatic Smart Indentation
***************************

Ada mode  comes with a full set of  rules for automatic indentation. You can of course configure the  indentation as you want, by setting the value of a few variables.

As  always,  the  preferred  way  to  modify variables  is  to  use  the Ada->Customize menu  (don't forget  to save your  changes!). This will also show you some example of code where this variable is used, and hopefully make things clearer.

The relevant variables are the following:

ada-broken-indent           (default value: 2)
     Number of columns to indent the continuation of a broken line.

ada-indent                  (default value: 3)
     Width of the default indentation.

ada-indent-record-rel-type  (default value: 3)
     Indentation for record relative to type or use.

ada-indent-return           (default value: 0)
     Indentation for return relative to function (if ada-indent-return is greater than 0), or the open parenthesis (if ada-indent-return is negative or null).  Note that in the second case, when there is no open parenthesis, the indentation is done relative to function with the value of ada-broken-indent.

ada-label-indent            (default value: -4)
     Number of columns to indent a label.

ada-stmt-end-indent         (default value: 0)
     Number of columns to indent a statement end keyword on a separate line.

ada-when-indent             (default value: 3)
     Indentation for when relative to exception or case.

ada-indent-is-separate      (default value: t)
     Non-nil means indent is separate or is abstract if on a single line.

ada-indent-to-open-paren    (default value: t)
     Non-nil means indent according to the innermost open parenthesis.

ada-indent-after-return     (default  value: t)
     Non-nil  means that  the current  line will  also be  re-indented before inserting a newline, when you press RET.

Most of the  time, the indentation will be automatic,  i.e when you will press RET,  the cursor will move  to the correct  column on the next line.

However, you might want or  need sometimes to re-indent the current line or a set of  lines. For this, you can simply go  to that line, or select the lines,  and then press TAB. This  will automatically re-indent the lines.

Another mode of indentation exists that helps you to set up your indentation scheme. If you press C-c TAB, Ada mode will do the following:

  * Reindent the current line, as TAB would do.

  * Temporarily move the cursor to a reference line, i.e., the line that was used to calculate the current indentation.

  * Display at the bottom of the window the name of the variable that provided the offset for the indentation.

The exact indentation of the current line is the same as the one for the reference line, plus an offset given by the variable.

Once you know the name of the variable, you can either modify it through the usual Ada->Customize menu, or by typing M-x customize-variable RET in the Emacs window, and then give the name of the variable.

TAB
     Indent the current line or the current region.

M-C-\
     Indent lines in the current selected block.

C-c TAB
     Indent the current line and prints the name of the variable used for indentation.

Formatting Parameter Lists
**************************

To help you correctly align fields in a subprogram parameter list, Emacs provides one function that will do most of the work for you. This function will align the declarations on the colon (:) separating argument names and argument types, plus align the in, out and in out keywords if required.

C-c C-f
     Format the parameter list (ada-format-paramlist).

Automatic Casing
****************

Casing  of   identifiers,  attributes  and   keywords  is  automatically
performed while  typing when  the variable ada-auto-case  is set.
Every  time   you  press  a   word  separator,  the  previous   word  is
automatically cased.

You  can  customize  the  automatic  casing  differently  for  keywords, attributes and  identifiers. The  relevant variables are  the following: ada-case-keyword,          ada-case-attribute          and ada-case-identifier.

All these variables can have one of the following values:

downcase-word
     The  previous word  will simply  be in  all lower  cases.   For instance My_vARIable is converted to my_variable.

upcase-word
     The previous word will be  fully converted to upper cases.  For instance My_vARIable is converted to MY_VARIABLE.

ada-capitalize-word
     All letters, except the first one of the word and every letter after the _  character are  lower cased.  Other  letters are  upper cased.   For instance My_vARIable is converted to My_Variable.

ada-loose-case-word
     No letters is  modified in the previous word, except  the ones after the _ character that are  upper cased.  For instance My_vARIable is converted to My_VARIable.

These  functions, although they  will work  in most  cases, will  not be accurate sometimes. The  Ada mode allows you to  define some exceptions, that will always be cased the same way.

The idea  is to  create a dictionary  of exceptions,  and store it  in a file. This file should contain  one identifier per line, with the casing you   want   to   force.   The   default   name   for   this   file   is ~/.emacs_case_exceptions.  You can  of course  change  this name, through the variable ada-case-exception-file.

Note that  each line  in this file  must start  with the key  word whose casing  you want  to  specify. The  rest of  the  line can  be used  for comments  (explaining  for  instance  what  an  abbreviation  means,  as recommended in the Ada 95  Quality and Style, paragraph 3.1.4).  Thus, a good example for this file could be:

     DOD        Department of Defense
     Text_IO
     GNAT       The GNAT compiler from Ada Core Technologies

When  working on  project involving  multiple programmers,  we recommend that every  member of  the team  sets this variable  to the  same value, which  should  point  to  a  system-wide  file that  each  of  them  can write.  That  way,  you  will  ensure  that  the  casing  is  consistent throughout your application(s).

There are two ways to add new items to this file: you can simply edit it as you  would edit any  text file, and  add or suppress entries  in this file.  Remember that  you should  put one  entity per  line.  The other, easier way, is to position the cursor  over the word you want to add, in an Ada buffer.  This word should have the casing  you want.  Then simply select  the  menu Ada->Edit->Create  Case  Exception,  or the  key C-c C-y. The word will  automatically be added to the current list of exceptions and to the file.

It  is sometimes  useful to  have multiple  exception files  around (for instance,  one could  be  the  standard Ada  acronyms,  the second  some company  specific exceptions,  and the  last one  some  project specific exceptions).  If you  set up the variable ada-case-exception-file as a list of  files, each of them will be parsed  and used in your emacs session.

However, when  you save a new  exception through the  menu, as described above, the  new exception will  be added to  the first file in  the list only.  You  can not automatically add  an exception to one  of the other files, although you can of course edit the files by hand at any time.

Automatic casing can be performed on port or whole buffer using:

C-c C-b
     Adjust case in the whole buffer.

C-c C-y
     Create a new entry in the exception dictionary, with the word under the cursor

C-c C-t
     Rereads the exception dictionary from the file ada-case-exception-file.

Statement Templates
*******************

NOTE:  This features  are  not available  on  VMS for  Emacs 19.28.  The functions used here do not exist on Emacs 19.28.

Templates exist  for most  Ada statements. They  can be inserted  in the buffer using the following commands:

C-c t b
     exception Block

C-c t c
     case.

C-c t d
     declare Block.

C-c t e
     else.

C-c t f
     for Loop.

C-c t h
     Header.

C-c t i
     if.

C-c t k
     package Body.

C-c t l
     loop.

C-c t t
     task Body.

C-c t w
     while Loop.

C-c t u
     use.

C-c t x
     exit.

C-c t C-a
     array.

C-c t C-e
     elsif.

C-c t C-f
     function Spec.

C-c t C-k
     package Spec.

C-c t C-p
     procedure Spec.

C-c t C-r
     record.

C-c t C-s
     subtype.

C-c t C-t
     task Spec.

C-c t C-u
     with.

C-c t C-v
     private.

C-c t C-w
     when.

C-c t C-x
     exception.

C-c t C-y
     type.

Comment Handling
****************

By default, comment lines get indented like Ada code. There are a few additional functions to handle comments:

M-;
     Start a comment in default column.

M-j
     Continue comment on next line.

C-c ;
     Comment the selected region (add -- at the beginning of lines).

C-c :
     Uncomment the selected region

M-q
     autofill the current comment.

Compiling Executing
*******************

Ada mode  provides a much complete environment  for compiling, debugging and running an application within Emacs.

All the  commands used  by Emacs to  manipulate your application  can be customized in  the project file.  Some default values are  provided, but these will  likely not  be good  enough for a  big or  even medium-sized project.  See the section on the  project file for an explanation on how to set up the commands to use.

One   of   the  variables   you   can   set   in  your   project   file, cross_prefix, indicates whether you are using a cross-compilation environment, and if  yes for which target. The  default command used for compilation  will add  this cross_prefix  in front  of  the name: gcc  will become  cross_prefix-gcc, gnatmake will become cross_prefix-gnatmake, ...

This  will also modify  the way  your application  is run  and debugged, although this is not implemented at the moment.

Here are the commands for building and using an Ada application

  * Compiling the current source This command is issued when  issuing the compile command from the Ada  menu. It  compiles  unconditionally the  current  source using  the comp_cmd variable of the project file. Compilation options can be customized with the variable comp_opt of the project file.

     Emacs  will  display  a new  buffer  that  contains  the result  of  the compilation.  Each line associated with an error will become active: you can simply click on it with the  middle button of the mouse, or move the cursor  on  it and  press  RET.  Emacs  will then  display  the relevant source file and put the cursor on the line and column the error was found at.

     You can also simply press the C-x ` key and Emacs will jump to the first error. If you press that key again, it will move you to the second error, and so on.

     Some error messages might also include references to some files. These references are also clickable in the same way.

  * (Re)building the whole application This command is issued when you select the build command from the Ada menu.   It compiles  all obsolete units  of the  current application using  the make_cmd  variable  of the  project file.  Compilation options  can be  customized  with the  variable  comp_opt of  the project  file, binder  options with  bind_opt and  linker options with link_opt. The main unit  of the application may be specified with main.

     The compilation buffer is also active in the same way it was for the above command.

  * Running the application This command is  issued when you select the  run command from the Ada   menu.   It   executes  the   current  application   in   an  emacs buffer. Arguments can be  passed through before executing. The execution buffer allows for interactive input/output.

     This   command   is   not   yet   available   in   a   cross-compilation toolchain. Emacs  would first need to  log on the  target before running the application. This will be implemented in a future release of Gnat.

Debugging your application
**************************

You  can set  up in  the project  file a  command to  use to  debug your application. Emacs is compatible with a lot of debuggers, and provide an easy interface to them.

This selection will focus on the  gdb debugger, and two of the graphical interfaces that exist for it.

In all  cases, the main  window in  Emacs will be  split in two:  in the upper  buffer,  the  source  code  will  appear,  whereas  the  debugger input/output  window is  displayed at  the  bottom.  You  can enter  the debugger  commands as  usual in  the command  window. Every  time  a new source file is  selected by the debugger (for instance as  a result of a frame command),  the appropriate source file is  displayed in the upper buffer.

The source window is interactive: you can click on an identifier with the right mouse button, and print its value in the debugger window. You can also set a breakpoint simply by right-clicking on a line.

You  can easily use  Emacs as  the source  window when  you are  using a graphical  interface for the  debugger. The  interesting thing  is that, whereas  you still  have the  graphical nifties,  you can  also  you the cross-references  features that  Ada mode  provides to  look  at the definition for the identifiers, ...

Here is how you  can set up gdbtk and ddd for  use with Emacs (These are the commands you should setup in the project file):

  * gdbtk should  be used  with  the  switch --emacs_gdbtk.   It  provides a  nice backtrace window, as well as a tasks window. You can click interactively on both of  them, and Emacs will display the source  file on the correct line.

  * ddd (Data Display Debugger) should be used with the switches --tty and --fullname. Whenever you print a variable from Emacs, it will be displayed graphically in the data window.

Using non-standard file names
*****************************

By default, Emacs is configured to  use the GNAT style file names, where file names are the package names,  and the extension for spec and bodies are respectively .ads and .adb.

If you  want to  use other  types of file  names, you will need to modify your .emacs file.

Adding new possible extensions is easy. Since Ada mode needs to know how to  go from  the body  to the spec  (and back),  you always  have to specify  both. A  function  is provided  with  Ada mode  to add  new extensions.

For instance, if your spec and bodies files are called UNIT_s.ada and UNIT_b.ada, respectively, you need to add the following to your .emacs file:

     (ada-add-extensions "_s.ada" "_b.ada")

Note that it is possible to redefine the extension, even if they already exist, as in:

     (ada-add-extensions ".ads" "_b.ada")
     (ada-add-extensions ".ads" ".body")

This simply means that whenever the  ada-mode will look for the body for a file whose extension is  .ads, it will take the first available file  that ends  with  either .adb  (standard), _b.ada  or .body.

If the filename is not the unit name, then things are a little more complicated.  You then need to rewrite the function ada-make-filename-from-adaname (see the file ada-mode.el for an example).

Working Remotely
****************

When  you work  on project  that  involve a  lot of  programmers, it  is generally the case that you will edit the files on your own machine, but you want to compile, run and debug your application in another buffer.

Fortunately, here too Emacs provides a very convenient way to do this.

Remote editing
==============

First of  all, the files do  not need to  be on your machine.  Emacs can edit any  remote file,  by doing transparent  FTP sessions  between your machine and the remote machine that stores your files. This is a special Emacs mode, called ange-ftp. To use it, you just have to use a slightly different syntax when you open a file.

For instance, if you want to  open the file /work/foo.adb on the machine aleph.gnu.org, where you log in as qwe, you would simply do this:

     C-x C-f /qwe@aleph.gnu.org:/work/foo.adb RET

i.e., use your name, the name of the machine and the name of the file.

The first time, Emacs will ask  you for a password that it will remember until you  close the current Emacs.  Even if the ftp  session times out, you won't need to reenter your password.

Every time you save the file, Emacs will upload it to the remote machine transparently. No file is modified on the local machine.

Remote compiling
================

If the  machine you  want to  compile on is  not the  one your  Emacs is running  on,  you can  set  the  variable  remote_machine in  the project file for your application.

This  will force  Emacs  to issue  a  rsh command  for the  compilation, instead of  running it on  the local machine. Unfortunately,  this won't work on Windows workstations, since this protocol is not supported.

     If  your   remote_machine  is  aleph.gnu.org   and  the  standard
     compilation command is cd /work/ && gnatmake foo, then Emacs will
     actually  issue  the  command  rsh  aleph.gnu.org  'cd  /work/  &&
     gnatmake foo'.

The advantage of using the  remote_machine variable is that it is easier to change  that machine without having to  modify the compilation command.

Note that if you need to set up some environment variables before the compilation, you need to insert a call to the appropriate initialization script in the compilation command, for instance:

     build_cmd= initialization_script; cd /work/ && gnatmake foo

Remote running and debugging
============================

This feature is not completely implemented yet.

However, most of the time, you will be able to run your application remotely simply by replacing it with a rsh call. For instance, if your command was ${main}, you could replace it with rsh aleph.gnu.org ${main}.

However, this would not work on vxworks, for instance, where rsh is not supported.