TraceInternal and OptionQ

*To*: mathgroup at smc.vnet.net*Subject*: [mg8949] TraceInternal and OptionQ*From*: tburton at cts.com (Tom Burton)*Date*: Mon, 6 Oct 1997 01:59:18 -0400*Organization*: Brahea Consulting*Sender*: owner-wri-mathgroup at wolfram.com

Olivier Gerard recently mentioned the option "TraceInternal" to the function "Trace". Wow! This is the first I've heard (seen) of this option. So far, I cannot find it in the MMA2 or MMA3 books or in MMA3 on-line docs. Yet it seems very useful--perhaps essential, on occasion. Is this an "undocumented" feature? Are users supposed to avoid it? If so, what alternative is there? Similarly, after reading about the function OptionQ in a third-party book, I began using it extensively to screen for options in argument lists, as in myFunc[matrix_?MatrixQ, label_String, opts___?OptionQ] :=3D body Recently, I noticed that the function "OptionQ" is similarly undocumented. In this case, I note that the pattern "opts___Rule" seems to perform the same function, perhaps a bit more elegantly, so I have began using "opts___Rule" in place of "opts___?OptionQ". Can anyone see a disadvantage to this substitution? Thanks. Tom