discard """ output: '''a[0]: 42 a[1]: 45 x: some string''' """ import macros macro debug(n: varargs[expr]): stmt = # `n` is a Nimrod AST that contains the whole macro invocation # this macro returns a list of statements: result = newNimNode(nnkStmtList, n) # iterate over any argument that is passed to this macro: for i in 0..n.len-1: # add a call to the statement list that writes the expression; # `toStrLit` converts an AST to its string representation: add(result, newCall("write", newIdentNode("stdout"), toStrLit(n[i]))) # add a call to the statement list that writes ": " add(result, newCall("write", newIdentNode("stdout"), newStrLitNode(": "))) # add a call to the statement list that writes the expressions value: add(result, newCall("writeln", newIdentNode("stdout"), n[i])) var a: array [0..10, int] x = "some string" a[0] = 42 a[1] = 45 debug(a[0], a[1], x)