Initial implementation of the parseExpr, parseStmt, getAst macro routines:

proc parseExpr*(s: string) : expr {.magic: "ParseExprToAst".}
  ## Compiles the passed string to its AST representation
  ## Expects a single expression

proc parseStmt*(s: string) : stmt {.magic: "ParseStmtToAst".}
  ## Compiles the passed string to its AST representation
  ## Expects one or more statements

proc getAst*(macroOrTemplate: expr): expr {.magic: "ExpandMacroToAst".}
  ## Obtains the AST nodes returned from a macro or template invocation
  ## example:
  ## macro FooMacro() = 
  ##   var ast = getAst(BarTemplate())

Handling of the node.toYaml magic moved to the evaluation engine.

tests/accept/compile/tdumpast.nim

@@ -1,12 +1,27 @@
 # Dump the contents of a PNimrodNode
 
 import macros
+
+template plus(a, b: expr): expr =
+  a + b
+
+macro call(e: expr): expr =
+  return newCall("foo", newStrLitNode("bar"))
   
-macro dumpAST(n: stmt): stmt = 
+macro dumpAST(n: stmt): stmt =
   # dump AST as a side-effect and return the inner node
   echo n.prettyPrint
   echo n.toYaml
 
+  var plusAst = getAst(plus(1, 2))
+  echo plusAst.prettyPrint
+
+  var callAst = getAst(call())
+  echo callAst.prettyPrint
+
+  var e = parseExpr("foo(bar + baz)")
+  echo e.prettyPrint
+
   result = n[1]
   
 dumpAST:
@@ -15,4 +30,3 @@ dumpAST:
   
   proc sub(x, y: int): int = return x - y
 
-