Overview

Preliminaries

The C_Shape_Edit User's Manual describes the use of the Alpha_1 c_shape_edit modeling program and command language interface. See the Model Repository for some examples of what you can do with C_Shape_Edit. shape3d is a TCL/Tk based "Dual View" graphical user interface to c_shape_edit which combines the strengths of the graphical and command language interfaces.

To get a quick overview and introduction to Alpha_1, see the Alpha_1 Introduction. To get set up to use Alpha_1, see Getting Started with Unix. For an overview of typical system-wide usage, including c_shape_edit examples, see the Alpha_1 Tutorial.

Running C_Shape_Edit

C_shape_edit can be run from the Unix shell or within the GNU emacs text editor as a subprocess (see GNU Emacs SCL Mode). C_shape_edit runs as a network process so 3D viewing programs (e.g.: motif3d) can connect to it. See the System Overview section of the Alpha_1 Introduction. Also see the Graphical Interaction section of the C_Shape_Edit User's Manual.

Basic Interaction

C_shape_edit is an interactive program based on a command language interface. This language is called Shape_edit Command Language or SCL (see below). C_shape_edit reads an SCL statement as input, evaluates the statement, and prints the result as output. This cycle is known as the top-loop. When started, c_shape_edit prints the following:

Alpha1 C++ Shape Editor
1 shape_edit>

The top-loop is waiting for the first command statement to be entered. When a statement is entered, it is evaluated, the result is printed, and a new prompt is printed:

Alpha1 C++ Shape Editor
1 shape_edit> 2 + 3;
5
2 shape_edit>

The top-loop cannot complete this cycle until a complete statement is read. When a partial statement has been entered, the prompt is changed to remind the user that the statement needs to be completed. The user can then complete the statement and the top-loop will complete its cycle.

Alpha1 C++ Shape Editor
1 shape_edit> 2 + 3;
5
2 shape_edit> 2 +
2 need_more_input> 3;
5
3 shape_edit>

When using c_shape_edit with motif3d for interactive viewing it is important that you enter complete statements. When partial statements are entered (and the need_more_input> prompt is seen) c_shape_edit cannot communicate with client graphics applications until the statement has been completed.

The emacs interface automatically reads input until a compete statement has been read. The top-loop keeps a running count of statements evaluated. This is reflected in the prompt. There is currently no history mechanism for repeating past commands.

Exiting C_Shape_Edit

Exiting c_shape_edit is accomplished with the quit; command or by typing the end-of-file character Ctl-D (^D).

3 shape_edit> quit;
Bye!

The Command Language

Two documents are available describing the structure of SCL. Beginning users should first read the C_shape_edit Command Language Reference which is an informal description of basic SCL syntax and structure. The C_shape_edit Command Language Specification formally describes the complete syntax and grammar of SCL.

C_Shape_Edit User's Manual Home Page

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