A macro is a function that's evaluated at compile time rather than at runtime. Clearly the compiler needs some mechanism to distinguish between the two, correct?
Clojure already has metadata and functions, so using a metadata flag on the var introduces no new types. It also has the advantage of being able to resolve a symbol as a macro before retrieving its content. It's not the only way Clojure could have distinguished macros from normal functions, but it's a simple and efficient solution. - James On 25 May 2014 23:20, Angel Java Lopez <ajlopez2...@gmail.com> wrote: > I see that macro are defined with associated metadata :macro true in its > associated var. > > Evaluate: > > (meta (var defn)) > > and you see the :macro true in metadata > > Why? In other lisp, macro are the result of evaluate (mlambda ... ) or > something alike, that is, macro are values that are evaluated in an special > way, as special forms (no evaluation of arguments) and then, the result is > evaluated. Normal functions are (lambda .... ) like (fn .... ) in Clojure. > As macros are values, they can be passed as arguments (map amacro ....) > could be evaluated (I guess). In Clojure, you must write (map (var amacro) > ... ) > > Why in Clojure the macro are defined using metadata, instead of something > like (mlambda ... ) or (mfn ... )? > > My first guess: this way of doing macro was related with compile to Java > > Angel "Java" Lopez > @ajlopez > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
