Channel - Basic (textual) I/O channel

Description:

The Channel class implements low-level input/output for the AST library. Writing an Object to a Channel will generate a textual representation of that Object, and reading from a Channel will create a new Object from its textual representation.

Normally, when you use a Channel, you should provide "source" and "sink" routines which connect it to an external data store by reading and writing the resulting text. By default, however, a Channel will read from standard input and write to standard output. Alternatively, a Channel can be told to read or write from specific text files using the SinkFile and SourceFile attributes, in which case no sink or source function need be supplied.

Constructor Function:

AST_CHANNEL

Inheritance

The Channel class inherits from the Object class.

Attributes

In addition to those attributes common to all Objects, every Channel also has the following attributes:

• Comment: Include textual comments in output?

• Full: Set level of output detail

• Indent: Indentation increment between objects

• ReportLevel: Selects the level of error reporting

• SinkFile: The path to a file to which the Channel should write

• Skip: Skip irrelevant data?

• SourceFile: The path to a file from which the Channel should read

• Strict: Generate errors instead of warnings?

Functions

In addition to those routines applicable to all Objects, the following routines may also be applied to all Channels:

• AST_WARNINGS: Return warnings from the previous read or write

• AST_READ: Read an Object from a Channel

• AST_WRITE: Write an Object to a Channel