RE: MakeExpression
- To: mathgroup at smc.vnet.net
- Subject: [mg33646] RE: [mg33613] MakeExpression
- From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
- Date: Thu, 4 Apr 2002 19:40:10 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
> -----Original Message----- > From: Dustin Vink [mailto:d.vink at mech.gla.ac.uk] To: mathgroup at smc.vnet.net > Sent: Thursday, April 04, 2002 1:08 AM > To: mathgroup at smc.vnet.net > Subject: [mg33646] [mg33613] MakeExpression > > > Dear Reader, > > Consider the following Mathematica problem. How does one incorporate > pattern matching conditions with the command MakeExpression? > > The following does NOT work: > > MakeExpression[RowBox[{a_Plus, "[", b__, "]"}], StandardForm] := > MakeExpression[a, StandardForm] > > Any form of condition used at the lhs seems to be ignored. > > > Dustin, what do you want to attain? MakeExpression acceptes (only) parsed input (structures of tokenized strings and boxes); the function itself generates Mathematica code (thus corresponding to the semantic actions of a compiler). A consequence is: the Mathematica symbol Plus can never appear as an argument of MakeExpression. Thus you came to your (false) conclusion. To help you further you should state your problem (of application). -- Hartmut