trace package:hxt

apply a trace arrow and issue message to stderr
trace a main computation step issue a message when trace level >= 1, issue document source if level >= 3, issue tree when level is >= 4
issue a string message as trace
issue the source representation of a document if trace level >= 3 for better readability the source is formated with indentDoc
an old alias for traceValue
issue the tree representation of a document if trace level >= 4
trace the current value transfered in a sequence of arrows. The value is formated by a string conversion function. This is a substitute for the old and less general traceString function
the trace arrows
acces the command for trace output
read the global trace level
set the global trace command. This command does the trace output
set the global trace level
withTrace level : system option, set the trace level, (0..4)
run an arrow with a given trace level, the old trace level is restored after the arrow execution