Implement isExported for symbols in macros (#11963)

* Implement isExported for macros

* Reimplement isExported using VM callback mechanism

* VM does not support exceptions, use stacktrace() instead.

compiler/vmops.nim

@@ -146,5 +146,14 @@ proc registerAdditionalOps*(c: PCtx) =
 
   registerCallback c, "stdlib.macros.symBodyHash", proc (a: VmArgs) {.nimcall.} =
     let n = getNode(a, 0)
-    if n.kind != nkSym: raise newException(ValueError, "node is not a symbol")
+    if n.kind != nkSym:
+      stackTrace(c, PStackFrame(prc: c.prc.sym, comesFrom: 0, next: nil), c.exceptionInstr,
+                  "symBodyHash() requires a symbol. '" & $n & "' is of kind '" & $n.kind & "'", n.info)
     setResult(a, $symBodyDigest(c.graph, n.sym))
+
+  registerCallback c, "stdlib.macros.isExported", proc(a: VmArgs) {.nimcall.} =
+    let n = getNode(a, 0)
+    if n.kind != nkSym:
+      stackTrace(c, PStackFrame(prc: c.prc.sym, comesFrom: 0, next: nil), c.exceptionInstr,
+                  "isExported() requires a symbol. '" & $n & "' is of kind '" & $n.kind & "'", n.info)
+    setResult(a, sfExported in n.sym.flags)

lib/core/macros.nim

@@ -1611,3 +1611,6 @@ when defined(nimMacrosSizealignof):
     ## from a field of a type. Therefore it only requires one argument
     ## instead of two. Returns a negative value if the Nim compiler
     ## does not know the offset.
+
+proc isExported*(n: NimNode): bool {.noSideEffect.} =
+  ## Returns whether the symbol is exported or not.

tests/macros/tisexported.nim

@@ -0,0 +1,10 @@
+import macros
+
+proc t1* = discard
+proc t2 = discard
+
+macro check(p1: typed, p2: typed) =
+  doAssert isExported(p1) == true
+  doAssert isExported(p2) == false
+
+check t1, t2