4 ms·

Can the user define a macro in Mathematica language?

• evanb 11y ago
  It's not quite so clear as that. In Mma you can give special meanings to any patterns of symbols you like, which is very much like defining a macro.
• taliesinb 11y ago
  There aren't read-time macros (yet). I'm actually in the process of designing a new package system that solves this (among many other problems).
• tokipin 11y ago
  the concept of "macros" in Mathematica doesn't really exist as its own concept because the whole system is based on rewriting structure. for example, the ReplaceAll function[1] which is commonly used in idiomatic code is basically an in-place macro definition and execution, yet it wouldn't occur to most people that it's anything special. if you're trying to make a traditional macro, you would implement it as a function with the HoldFirst et al attribute. an important thing to know is that ReplaceAll uses arbitrary structural patterns. it's not a simple "turn every a into b". you can say things like "turn every application of the symbol F on an even number into an application of G on that number divided by two". expr /. F[n_?EvenQ] :> G[n/2] [1] https://reference.wolfram.com/language/ref/ReplaceAll.html https://reference.wolfram.com/language/ref/ReplaceAll.html