2.2. Starting SCE
SCE is invoked by entering
% sce
at the command line prompt (%). This will start the application and open the main window (Chapter 3) of the combined SCE graphical user interface (GUI).2.2.1. Scripting
SCE supports scripting of the complete environment from the command line without the need to invoke the GUI. For scripting purposes, a GUI-less command shell of SCE can be invoked by entering
% scsh
at the command line prompt (%). This will start the SCE shell without the GUI layer. Instead, a prompt (>>) is offered to enter commands that allow to drive the SCE environment interactively (or from SCE shell scripts read from files supplied on the scsh command line).The SCE shell is based on an embedded Python interpreter [8]. As such, it conforms to Python syntax and the full semantics of the Python language is available. In addition, the SCE shell extends the Python interpreter with an API for access to SCE functionality. However, the SCE shell API only provides undocument low-level access to SCE internals for developers.
For user-level scripting of SCE by designers, a complete set of high-level scripts on top of the SCE shell are available. The set of scripts provides a convenient command-line interface for all necessary SCE functionality (see Appendix B). Together with command-line interfaces to model refinement tools (Appendix C) and to the SpecC compiler (Appendix D), complete scripting of the SCE design flow from the command line, through shell scripts or via Makefiles is possible.
2.2.2. Environment Variables
HOMEDetermines the location of the user's home directory and consequently the default path to the file with user-specific application preferences ($
HOME/.sce/scerc).SCERC_PATHDetermines the list of directories where files serrc with user-specific application preferences (see Section 4.1) are stored. Multiple directories can be provided, separated by colons (":"). Directories are searched for and preference files are read in the given order, i.e. preference files in later directories can override settings in earlier ones. Modified preferences will be written to the first directory in the list that is writeable by the user.
If
SCERC_PATHis not set, the location (directory) of the user-specific serrc file defaults to $HOME/.sce.SPECCDetermines the installation directory of the SpecC compiler and SIR libraries. Default settings for the include path (directory $
SPECC/inc) and the import path (directory $SPECC/import) in the compiler settings of the application preferences (see Section 4.1) are derived from this variable.SPECC_LICENSE_FILEDetermines the path to the license file (directory and file name) for the SpecC compiler and SIR libraries (see Appendix D). If undefined, the environment variable
SPECCis used as the path to the license file called license.sir. If neitherSPECC_LICENSE_FILEnorSPECCexist, the file license.sir is searched in the current directory.
2.2.3. Files
- /opt/sce/etc/scerc
File with system-wide default settings for application preferences (see Section 4.1). System-wide settings are read on application startup before user-specific settings.
If the system-wide application preferences file is writable by the user, application preferences will be stored in the system-wide file (instead of the user-specific one) and any changes to preferences will overwrite system-wide settings.
- $
SCERC_PATH/scerc or $HOME/.sce/scerc File(s) with user-specific settings for application preferences. (see Section 4.1). User-specific settings are read on application startup after system-wide settings, i.e. user-specific settings overwrite system-wide settings. Application preferences are written into the user-specific preferences file on application exit.