Re: help functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg2457] Re: help functions*From*: wagner at goober.cs.colorado.edu (Dave Wagner)*Date*: Wed, 8 Nov 1995 23:46:41 -0500*Organization*: University of Colorado, Boulder

In article <47mtoi$4nd at ralph.vnet.net>, Jack Goldberg <jackgold at math.lsa.umich.edu> wrote: >Hi group; > >For starters, suppose that we try to define > > Help[x_String] := Module[ ... ] > >I don't know how to access the comments produced by ? from within >my module. I suppose there is some trick that fools mma into thinking >I'm using ?, but I can't think of any. And ? doesn`t help. Jack, ?symbol is just a special input form for Information[symbol]: (Local) In[23]:= Information[Table] Table[expr, {imax}] generates a list of imax copies of expr. Table[expr, {i, imax}] generates a list of the values of expr when i runs from 1 to imax. Table[expr, {i, imin, imax}] starts with i = imin. Table[expr, {i, imin, imax, di}] uses steps di. Table[expr, {i, imin, imax}, {j, jmin, jmax}, ...] gives a nested list. The list associated with i is outermost. Attributes[Table] = {HoldAll, Protected} Note, however, that the information is printed, not returned, so you can't modify it programmatically. But why not go straight to the source and use symbol::usage: (Local) In[26]:= Table::usage (Local) Out[26]= Table[expr, {imax}] generates a list of imax copies\ of expr. Table[expr, {i, imax}] generates a list of\ the values of expr when i runs from 1 to imax.\ Table[expr, {i, imin, imax}] starts with i = imin.\ Table[expr, {i, imin, imax, di}] uses steps di.\ Table[expr, {i, imin, imax}, {j, jmin, jmax}, ...]\ gives a nested list. The list associated with i is\ outermost. Note the "Out" label. You can capture this string in a variable and do whatever you want with it before printing it. By the way, why are you trying to define Help[x_String]? Why not Help[x_Symbol] instead? Give the function the HoldFirst attribute and you should have no problems, because "::" will also hold its argument. Dave Wagner Principia Consulting (303) 786-8371 dbwagner at princon.com http://www.princon.com/princon