The Console Window

Overview

If the PrologJ system is started up by double-clicking the prologj.jar file, or is started from the command line with the -w[indow] option specified, a console window like the following is displayed. The window can be used for interacting with the interpreter, and a menu option is provided to allow compiling a file. Interactive user input is typed in the main text area in the window, and program output is displayed in this area as well.

Console Window Menus

The console window provides the following menus:

• The File menu
   
  • The Open option can be used to load a database previously saved using the Save option. An open file dialog is displayed to allow the user to select a saved database to be loaded. The library selection, predicate and operator definitions, flag and character conversion settings, and loaded file and debugging state read from the file completely replace the current values. The required extension for a saved database is ".prs".
     
  • The Save option can be used to save a database to a file. A save file dialog is displayed to allow the user to select the a name for the file which will contain the saved database. Information about the current library selection, current predicate and operator definitions, current flag and character conversion settings, and the current loaded file and debugging state is saved in the file. The required extension for a saved database is ".prs".
     
    Note that any changes to the database made by built-in predicates such as asserta/1 are not saved on disk unless explicitly saved by using this option.
     
  • The Quit option can be used to halt the PrologJ system.
  
   
• The Interpreter menu
   
  • The Consult option can be used to consult a source file. An open file dialog is displayed to allow the user to choose a source file to read, which is then processed as if by the built-in predicate consult/1. The required extension for a Prolog source file is ".pro".
     
    The menus in the menu bar are temporarily disabled (grayed out) while the selected file is being consulted. The process of consulting the file can be aborted at any time by clicking the Abort button.
     
  • The Reconsult option can be used to reconsult a source file. (The definition for any predicate that occurs in the file completely replaces the existing definition for that predicate; but any predicate not defined in the file is left unchanged.) An open file dialog is displayed to allow the user to choose a source file to read, which is then processed as if by the built-in predicate reconsult/1. The required extension for a Prolog source file is ".pro".
     
    The menus in the menu bar are temporarily disabled (grayed out) while the selected file is being reconsulted. The process of reconsulting the file can be aborted at any time by clicking the Abort button.
     
• The Compiler menu
   
  • The Compile option can be used to compile a source file, as described in the compiler documentation. The compilation process is carried out in accordance with the options specified by the remaining items in this menu. The required extension for a Prolog source file is ".pro".
     
    The menus in the menu bar are temporarily disabled (grayed out) while the selected file is being compiled. The process of compiling the file can be aborted at any time by clicking the Abort button.
     
  • The Java option is a checkbox option that controls whether the compiler output is processed by javac to produce a .class file (when this item is deselected - the default), or whether the compilation process stops with the production of a Java source file (when this item is selected). This checkbox is equivalent to the command line -j[ava] option.
     
  • The Verbose option is a checkbox option that controls whether verbose compiler output is produced. Verbose output, if requested, is displayed in the console window. This checkbox is equivalent to the command line -v[erbose] option.
     
  • The Directory option can be used to specify a directory to receive the compiler output (compiled .class file or Java source code as the case may be.) When this option is selected, a file dialog is displayed which allows the user to choose a directory. If one is chosen, it becomes the directory for subsequent compiler output, and this menu option is displayed as checked. (If the compiler is producing a .class file as output, and the source file contains a :- package/1 directive, the compiled file will actually go into a subdirectory of the selected directory.) If the user cancels the file dialog, the current working directory is used for compiler output, and this menu option is displayed as unchecked. This menu option is equivalent to the command line -d[irectory] option.
     
• The Library Components menu provides check-box options allowing the user to enable/disable selected components of the library of built-in predicates, as discussed in the documentation for the built-in predicates.
   
• The Flags menu provides a single Show option which displays a dialog box that shows - and allows the user to alter - the settings of each of the changeable flags, and which simply shows the settings of each of the unchangeable flags, as discussed in the documentation for the flags. Once this dialog box is displayed, it remains visible (and is updated whenever a flag's value is changed) until the user dismisses it. (Note: the flags denoting the availability of various library components are not changeable through this dialog box, but are changed if changes are made using the Library Components menu.)

Buttons

Three buttons appear at the top of the window.

• The Clear button clears the text displayed in the console.
   
• The EOF button can be used to enter an end-of-file condition to the console. If this button is pressed while consulting a file interactively (as a result of entering the [user] command), it terminates consultation mode and returns the console to interpretation mode. If it is pressed while executing a break loop, it terminates the break look and returns to the previous mode. If it is pressed when in the "top level" interpretation loop, it terminates the program.
   
• The Abort button can be used to immediately terminate the current computation. This includes computations started by choosing the Consult, Reconsult, or Compile menu options, as well as computations initiated by typing a goal or file consultation command at the interpreter's ?- prompt.

Copyright © 2005 - Russell C. Bjork. See the file See file COPYING in the root directory for copyright information.