LLOOP Usage

This page explains how to run the generator and gives a detailed description of the possible options.

Overview

The LLOOP generator is a standalone and command-line application. The name of the command line executable itself is gspc[.exe] which stands for GSP Compiler. gspc configures either from command line options or from explicit user configuration file or a mix of both.

However, the most convenient way to use and control it is to use its graphical front-end GFE LLOOP of which you see a screenshot above. The GFE executable file is gfelloop[.exe].

GFE makes it straightforward to exploit all functionality of the tool, as its graphical user interface eases a lot the configuration process and makes transparent how gspc is run and technically configured. Moreover, it allows to handle your configuration parameters in a project-oriented way (.lloop files):

• Create, open, save or "save as" your project using the menus or toolbar buttons
• Use the entry panel at the right to enter the configuration parameters
• Enter your settings for the generated C++ code, eg. output directories, through the C++ Option Set window
  
• If required, enter your custom makefile settings for building your executable or library through the Makefile Advanced Option Set window
  
• Each entry is fully documented when you click on the entry field. The documentation is shown either in the leftmost help window or in a yellow popup window.
• Multiple values which have to be entered manually must be separated by comas.
• Click on the run button to start the generation.
• Check executed commands and results in the log window that captures all standard outputs.

Generation Project Directory

A generation is always tied with a directory, called "project directory":

• When gspc is run directly on command line, the current working directory is used as project directory.
• When gspc is run from the Graphical Front End, the directory of the .lloop project file is used as project directory. The GFE automatically switches to this directory before executing gspc.

Every generated files and any reference to other files are dealt with relatively to the project directory.

All information related to the last generation is stored in the project directory, below the hidden .gspc/ sub-directory. There are stored the list of all generated files as well as configuration parameters used in last generation. The .gspc/ sub-directory is managed automatically and transparently by gspc and shall never be modified manually.

Configuration

• Overview

There are actually three ways to configure the generator:

• The graphical interface GFE
• Command line
• Explicit configuration file

• Using the GFE

This is the most convenient way to configure gspc, at least for the first time the project is set up.

The user has just to click on the icon to start the generation.

The GFE automatically builds the entire command line arguments from the entered data in the GUI and passes them always explicitly to gspc, ensuring previously stored parameters inside .gspc/ are cleaned up.

• Using command line

When only command line options are used, all configuration parameters are kept persistent below the .gspc/, and gspc always attempt to read them back and use them.

  In that case, it is sufficient to invoke gspc without any argument simply to replay a generation.

  Explicit command line options always take precedence and override any persistent configuration parameters, either stored below .gspc/ or within an explicit configuration file.

• Using explicit configuration file

When an explicit configuration file "gspc.cfg" is present in the project directory, gspc will also use the parameters defined there.

Configuration parameters inside the configuration file are specified exactly as they are given by command line, except that they can additionally be given on multiple lines.

When an explicit configuration file is used, previously saved configuraton parameters below the .gspc/ are never used.

  It is recommended to not use explicit user configuration files, except if the GFE can not be run or is never used.

Environment Setup for running gspc on command line

• Overview

The following information are provided as support when running gspc directly on command line and not with the graphical interface.

gspc runs similarly on all operating systems. On Windows systems, it is run from a MS-DOS command interpreter. On UNIX systems it is run from your usual shell.

To get a concise list of available options, type gspc --.

To get a comprehensive documentation on available options, type gspc -h.

• Under UNIX or alike systems

gspc runs from your usual shell or terminal.

When LLOOP is installed from the RPM file, the default shell environment is updated as follows:

• The PATH variable is updated in order to find the gspc executable.
• The "g" alias is defined to relieve the user from specifying every time the --license-file and --gsp-path options.
• The "xg" alias is defined to start GFE LLOOP.

During installation, the resource files gspcrc.sh and gspcrc.csh for resp. standard shells and CSH shells are copied below /etc/profile.d.

• Under Windows NT, 2000 or later

gspc runs from the MS-DOS command interpreter.

The MS-DOS command interpreter can be executed from the desktop by clicking Start, selecting the Run menu and executing the cmd application.

For using gspc you may set your PATH variable to relieve you from specifying the full path of the generator to run it. This can be done as follows:

• Click on Start
• Click on Configuration Panel
• Click on System Properties
• In the System Properties windows, select Advanced
• From there you can then change your environment variables. Select the PATH variable and complete it with the following line, for example, if you installed LLOOP directly on drive C:

  ;C:\LLOOP\

• Apply the change
• From now the executable will be in your PATH for any newly created MS-DOS command interpreter

• Under Windows 95 or earlier

gspc runs from the MS-DOS command interpreter.

The MS-DOS command interpreter can be executed from the desktop by clicking Start, selecting the Run menu and executing the command application.

For using gspc you may set your PATH variable to relieve you from specifying the full path of the generator to run it. This can be done as follows:

• Edit the file C:\autoexec.bat
• Complete the definition of the PATH environment variable with the following line, if you installed LLOOP under C:\LLOOP:

;C:\LLOOP\

An example of resulting PATH line could be:

PATH C:\WINDOWS;C:\WINDOWS\COMMAND;C:\LLOOP\

• Restart your computer

Example of use

The GFE project files (.lloop) which allow to compile and run all examples are part of the release package and can be found below the examples directory.

In particular, the examples.lloop project allows to compile and run in batch all examples.

Check this link to get more information about the provided examples.

This file is part of the LLOOP Reversible Object-Oriented Parser Generator. Copyright (c) 2005-2006 Michel MEHL, France. All rights reserved. LLOOP is distributed by the company ERSA SaRL.