new special forms

*To*: mathgroup at yoda.physics.unc.edu*Subject*: new special forms*From*: madler at cco.caltech.edu (Mark Adler)*Date*: 6 May 1994 00:50:47 GMT

Mathematica provides ~ for using a function in infix form. However, I would like a way to make my own special forms that don't need ~. For example, I'd like 3_-5 to mean 3 10^-5. In the quest for a way to enter numbers in scientific notation more easily, I came up with this kludge: Unprotect[StringJoin] StringJoin[m_?NumberQ,e_?NumberQ] := m 10^e Protect[StringJoin] Then 3<>-5 gives 3 10^-5, and does not interfere with the normal operation of <>. This has two drawbacks: a) it's a little cumbersome to type and so is only marginally better than blank 10^, and b) the precedence is high, but not quite high enough, since something like (#^2)& @ 3<>-5 gives 9 10^-5 instead of 9 10^-10. So, the questions are: is there any way to define my own special form with my own specified precedence and operation? Is there a way to redefine a higher precedence form like ? or :: (I couldn't find a way)? Is there some other completely different approach to this problem? Thanks. mark