Fields

Fields name parts of a phrase for content manipulation in various ways.

field name = contents
  • name is an identifier that refers to the field.
  • contents is any phrase structure, except that it cannot contain another field.

A field is used to:

  • Delineate part of the data portion of the message.
  • Indicate where outbound data is interpolated.
  • Store a length-encoding.

Store an encoded phrase-check value. When a phrase is read (set up using the hci_pd_receive Tcl command), the corresponding continuation is called with a keylist. The keylist associates the field names with the input region that contains their value. When a phrase is written, the engine uses the field’s value without regard to its content structure.

The restrictions on the field contents during reading do not apply when writing; you must ensure the protocol is satisfied.