The VIEW command adjusts an environmental factor selected by a keyword argument. For example, VIEW controls journal buffer flushing, determines whether GT.M reports undefined variables as errors or treats them as null, and determines which BREAK commands should display messages.
The format of the VIEW command is:
V[IEW][:tvexpr] keyword[:expr2[:...]][,...]
The optional truth-valued expression immediately following the command is a command postconditional that controls whether or not GT.M executes the command.
The keyword specifies the environmental factor to change.
The optional expression following the keyword specifies the nature of the change to the environmental factor.
An indirection operator and an expression atom evaluating to a list of one or more VIEW arguments form a legal argument for a VIEW