support -d:yamlDebug at CT

yaml/parser.nim

@@ -125,11 +125,6 @@ proc afterPairValue(c: Context, e: var Event): bool
 proc emitCached(c: Context, e: var Event): bool
 {.pop.}
 
-template debug(message: string) {.dirty.} =
-  when defined(yamlDebug):
-    try: styledWriteLine(stdout, fgBlue, message)
-    except ValueError, IOError: discard
-
 template pushLevel(c: Context, newState: State, newIndent: int) =
   debug("parser: push " & newState.astToStr & ", indent = " & $newIndent)
   c.levels.add(Level(state: newState, indentation: newIndent))

yaml/private/lex.nim

@@ -167,10 +167,13 @@ proc streamEnd(lex: var Lexer): bool {.raises: [].}
 
 # helpers
 
-template debug(message: string) {.dirty.} =
+template debug*(message: string) =
   when defined(yamlDebug):
-    try: styledWriteLine(stdout, fgBlue, message)
-    except ValueError, IOError: discard
+    when nimvm:
+      echo "yamlDebug: ", message
+    else:
+      try: styledWriteLine(stdout, fgBlue, message)
+      except ValueError, IOError: discard
 
 proc generateError(lex: Lexer, message: string):
     ref LexerError {.raises: [].} =