Re: HoldForm in defined function doesn't seem to work

*To*: mathgroup at smc.vnet.net*Subject*: [mg99235] Re: [mg99182] HoldForm in defined function doesn't seem to work*From*: "Scot T. Martin" <smartin at seas.harvard.edu>*Date*: Thu, 30 Apr 2009 06:25:01 -0400 (EDT)*References*: <200904291037.GAA26696@smc.vnet.net>

Joel, The problem is that Mathematica evaluates your argument BEFORE calling x, I believe. This will work for you, I think. f[x_] := FullForm[x]; f[Hold[1 3 6]] then returns Hold[Times[1,3,6]] Perhaps that is what you're after.... Scot On Wed, 29 Apr 2009, joel.aufgang at gmail.com wrote: > I'm struggling to understand why this doesn't work: > > > f[x_] = HoldForm[x]; > HoldForm[123 456 789] (* returns "123 x 456 x 789" *) > f[123 456 789] (* returns"44253432" *) > > I don't understand why the two results are different. Is there a > special trick I need to do to be able to define f so that the HoldForm > works? > > I'm using this to help visualize the way a notebook represents typed > expressions, so I'm trying to do something like this: > > BoxTree[expr_] := TreeForm[ToBoxes[HoldForm[expr]][[1]]]; > a b c d e // BoxTree > 123 456 789 // BoxTree (* want this to show as a RowBox like the > previous example *) > > > Any help would be greatly appreciated. Thanks. > >

**References**:**HoldForm in defined function doesn't seem to work***From:*joel.aufgang@gmail.com