Have preprocessor and assembler print to stdout instead of stderr

CHANGELOG.md

@@ -13,6 +13,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ### Changed
 - The `break` debugging command now prints the location of the breakpoint that it set.
+- The preprocess subcommand now prints its normal output to standard out instead of standard error.
 
 ### Fixed
 - When no file path is provided, the `break` debugging command defaults to the current file (whereas behavior was unpredictable before).

hera/main.py

@@ -85,21 +85,22 @@ def main_execute(path: str, settings: Settings) -> VirtualMachine:
 
 
 def main_preprocess(path: str, settings: Settings) -> None:
-    """Preprocess the program and print it to standard output."""
+    """Preprocess the program and print it to stdout."""
     program = load_program_from_file(path, settings)
     if program.data:
-        sys.stderr.write("[DATA]\n")
+        print("[DATA]")
         for data_op in program.data:
-            sys.stderr.write("  {}\n".format(data_op))
+            print("  {}".format(data_op))
 
         if program.code:
-            sys.stderr.write("\n[CODE]\n")
+            print("\n[CODE]")
 
     for i, op in enumerate(program.code):
-        sys.stderr.write("  {:0>4}  {}\n".format(i, op))
+        print("  {:0>4}  {}".format(i, op))
 
 
 def main_assemble(path: str, settings: Settings) -> None:
+    """Assemble the program into machine code and print the hex output to stdout."""
     program = load_program_from_file(path, settings)
     raw_code, raw_data = assemble(program)
 
@@ -108,17 +109,18 @@ def main_assemble(path: str, settings: Settings) -> None:
 
     if settings.stdout:
         if settings.data:
-            sys.stderr.write(data)
-            sys.stderr.write("\n")
+            print(data)
         elif settings.code:
-            sys.stderr.write(code)
-            sys.stderr.write("\n")
+            print(code)
         else:
-            sys.stderr.write("[DATA]\n")
-            sys.stderr.write(textwrap.indent(data, "  "))
-            sys.stderr.write("\n[CODE]\n")
-            sys.stderr.write(textwrap.indent(code, "  "))
+            print("[DATA]")
+            print(textwrap.indent(data, "  "))
+            print("\n[CODE]")
+            print(textwrap.indent(code, "  "))
     else:
+        if path == "-":
+            path = "stdin"
+
         with open(path + ".lcode", "w", encoding="ascii") as f:
             f.write(code)
 
@@ -256,7 +258,7 @@ def dump_state(vm, settings):
         nprint("\n{} warning{} emitted.".format(c, "" if c == 1 else "s"))
 
 
-def bytes_to_hex(b):
+def bytes_to_hex(b: bytes) -> str:
     try:
         return b.hex()
     except AttributeError:

test/test_assembler.py

@@ -5,57 +5,57 @@ def test_assemble_set_inc(capsys):
     main(["assemble", "--code", "--stdout", "test/assets/asm/set_inc.hera"])
 
     captured = capsys.readouterr()
-    assert captured.out == ""
+    assert captured.err == ""
 
     with open("test/assets/asm/set_inc.hera.lcode") as f:
-        assert captured.err == f.read()
+        assert captured.out == f.read()
 
 
 def test_assemble_binary_op(capsys):
     main(["assemble", "--code", "--stdout", "test/assets/asm/binary_op.hera"])
 
     captured = capsys.readouterr()
-    assert captured.out == ""
+    assert captured.err == ""
 
     with open("test/assets/asm/binary_op.hera.lcode") as f:
-        assert captured.err == f.read()
+        assert captured.out == f.read()
 
 
 def test_assemble_branch(capsys):
     main(["assemble", "--code", "--stdout", "test/assets/asm/branch.hera"])
 
     captured = capsys.readouterr()
-    assert captured.out == ""
+    assert captured.err == ""
 
     with open("test/assets/asm/branch.hera.lcode") as f:
-        assert captured.err == f.read()
+        assert captured.out == f.read()
 
 
 def test_assemble_flag(capsys):
     main(["assemble", "--code", "--stdout", "test/assets/asm/flag.hera"])
 
     captured = capsys.readouterr()
-    assert captured.out == ""
+    assert captured.err == ""
 
     with open("test/assets/asm/flag.hera.lcode") as f:
-        assert captured.err == f.read()
+        assert captured.out == f.read()
 
 
 def test_assemble_shift(capsys):
     main(["assemble", "--code", "--stdout", "test/assets/asm/shift.hera"])
 
     captured = capsys.readouterr()
-    assert captured.out == ""
+    assert captured.err == ""
 
     with open("test/assets/asm/shift.hera.lcode") as f:
-        assert captured.err == f.read()
+        assert captured.out == f.read()
 
 
 def test_assemble_misc(capsys):
     main(["assemble", "--code", "--stdout", "test/assets/asm/misc.hera"])
 
     captured = capsys.readouterr()
-    assert captured.out == ""
+    assert captured.err == ""
 
     with open("test/assets/asm/misc.hera.lcode") as f:
-        assert captured.err == f.read()
+        assert captured.out == f.read()

test/test_preprocessor.py

@@ -5,11 +5,11 @@ def test_preprocess_simple_program(capsys):
     preprocess_program_helper("SET(R1, 10)")
 
     captured = capsys.readouterr()
-    assert captured.out == ""
+    # TODO: Have it print the newline to stdout as well.
+    assert captured.err == "\n"
     assert (
-        captured.err
+        captured.out
         == """\
-
   0000  SETLO(R1, 10)
   0001  SETHI(R1, 0)
 """
@@ -20,11 +20,10 @@ def test_preprocess_data(capsys):
     preprocess_program_helper('LP_STRING("hello")')
 
     captured = capsys.readouterr()
-    assert captured.out == ""
+    assert captured.err == "\n"
     assert (
-        captured.err
+        captured.out
         == """\
-
 [DATA]
   LP_STRING("hello")
 """
@@ -35,11 +34,10 @@ def test_preprocess_data_and_code(capsys):
     preprocess_program_helper('DLABEL(s) LP_STRING("hello") SET(R1, s)')
 
     captured = capsys.readouterr()
-    assert captured.out == ""
+    assert captured.err == "\n"
     assert (
-        captured.err
+        captured.out
         == """\
-
 [DATA]
   LP_STRING("hello")
 
@@ -54,5 +52,5 @@ def test_preprocess_character_literal(capsys):
     preprocess_program_helper("SET(R1, 'A')")
 
     captured = capsys.readouterr()
-    assert captured.out == ""
-    assert captured.err == "\n  0000  SETLO(R1, 65)\n  0001  SETHI(R1, 0)\n"
+    assert captured.err == "\n"
+    assert captured.out == "  0000  SETLO(R1, 65)\n  0001  SETHI(R1, 0)\n"