Sandbox DumpParse tests...

and add a return value to DumpParse

Author: rocky

mathics/builtin/files_io/files.py

@@ -237,8 +237,10 @@ class DumpParse(Builtin):
       a Pickle file $output$. $True$ is returned if everthing want okay.
     </dl>
 
-    >> DumpParse["BoolEval/BoolEval.m", "/tmp/BoolEval.mx3"]
-     = ...
+    >S dumpParsedFile = FileNameJoin[{$TemporaryDirectory, "BoolEval.mx3"}]
+    >S DumpParse["BoolEval/BoolEval.m", dumpParsedFile]
+     = True
+    #> Clear[dumpParsedFile]
     """
 
     options = {

mathics/core/parser/util.py

@@ -13,12 +13,12 @@
 from mathics.core.parser.convert import convert
 from mathics.core.parser.feed import MathicsSingleLineFeeder
 from mathics.core.parser.parser import Parser
-from mathics.core.symbols import Symbol, ensure_context
+from mathics.core.symbols import Symbol, SymbolTrue, ensure_context
 
 parser = Parser()
 
 
-def dump_exprs_to_pcl_file(exprs, pickle_file: str) -> Optional[str]:
+def dump_exprs_to_pcl_file(exprs, pickle_file: str) -> Symbol:
     """
     Parse input from `feeder` and pickle serialize the parsed M-expression Python written
     to pickle_file.
@@ -28,6 +28,7 @@ def dump_exprs_to_pcl_file(exprs, pickle_file: str) -> Optional[str]:
     with open(pickle_file, "wb") as f:
         # Protocol -1 uses the highest available binary protocol for efficiency
         pickle.dump(exprs, f, protocol=pickle.HIGHEST_PROTOCOL)
+    return SymbolTrue
 
 
 def parse(definitions, feeder: LineFeeder) -> Optional[BaseElement]: