Improve render_trace's ASCII output.

examples/renderer-demo.py

@@ -85,8 +85,8 @@ def make_counter(period: int, bitwidth: int = 2):
     )
 
 for name, (constants, notes) in renderers.items():
-    print(f"# {notes}")
-    print(f"export PYRTL_RENDERER={name}\n")
+    print(f"# {notes}\n")
+    print(f"$ export PYRTL_RENDERER={name}\n")
     sim.tracer.render_trace(
         renderer=pyrtl.simulation.WaveRenderer(constants), repr_func=int
     )

pyrtl/simulation.py

@@ -1376,10 +1376,10 @@ class Utf8RendererConstants(RendererConstants):
 
     This is the default renderer.
 
-    Enable this renderer by default by setting the ``PYRTL_RENDERER`` environment
-    variable to ``utf-8``::
+    Use this renderer by default by setting the ``PYRTL_RENDERER`` environment variable
+    to ``utf-8``::
 
-        export PYRTL_RENDERER=utf-8
+        $ export PYRTL_RENDERER=utf-8
 
     .. image:: ../docs/screenshots/pyrtl-renderer-demo-utf-8.png
        :width: 35em
@@ -1417,10 +1417,10 @@ class Utf8AltRendererConstants(RendererConstants):
     Compared to :class:`Utf8RendererConstants`, this renderer is more compact because it
     uses one character between cycles instead of two.
 
-    Enable this renderer by default by setting the ``PYRTL_RENDERER`` environment
-    variable to ``utf-8-alt``::
+    Use this renderer by default by setting the ``PYRTL_RENDERER`` environment variable
+    to ``utf-8-alt``::
 
-        export PYRTL_RENDERER=utf-8-alt
+        $ export PYRTL_RENDERER=utf-8-alt
 
     .. image:: ../docs/screenshots/pyrtl-renderer-demo-utf-8-alt.png
        :width: 25em
@@ -1456,10 +1456,10 @@ class PowerlineRendererConstants(Utf8RendererConstants):
     This renderer requires a `terminal font that supports Powerline glyphs
     <https://github.com/powerline/fonts>`_.
 
-    Enable this renderer by default by setting the ``PYRTL_RENDERER`` environment
-    variable to ``powerline``::
+    Use this renderer by default by setting the ``PYRTL_RENDERER`` environment variable
+    to ``powerline``::
 
-        export PYRTL_RENDERER=powerline
+         $ export PYRTL_RENDERER=powerline
 
     .. image:: ../docs/screenshots/pyrtl-renderer-demo-powerline.png
        :width: 35em
@@ -1487,10 +1487,10 @@ class Utf8BasicRendererConstants(RendererConstants):
     codes <https://en.wikipedia.org/wiki/ANSI_escape_code>`_, which makes its output
     suitable for inclusion in text files.
 
-    Enable this renderer by default by setting the ``PYRTL_RENDERER`` environment
-    variable to ``utf-8-basic``::
+    Use this renderer by default by setting the ``PYRTL_RENDERER`` environment variable
+    to ``utf-8-basic``::
 
-        export PYRTL_RENDERER=utf-8-basic
+        $ export PYRTL_RENDERER=utf-8-basic
 
     .. image:: ../docs/screenshots/pyrtl-renderer-demo-utf-8-basic.png
        :width: 25em
@@ -1515,23 +1515,26 @@ class Utf8BasicRendererConstants(RendererConstants):
 class AsciiRendererConstants(RendererConstants):
     """7-bit ASCII renderer constants. These should work anywhere.
 
-    Single-bit :class:`WireVectors<WireVector>` are rendered as waveforms with sloped
-    rising and falling edges. Multi-bit :class:`WireVector` values are rendered between
-    vertical bars.
+    Single-bit :class:`WireVectors<WireVector>` are rendered as square waveforms with
+    vertical rising and falling edges. Multi-bit :class:`WireVector` values are rendered
+    between vertical bars.
 
-    Enable this renderer by default by setting the ``PYRTL_RENDERER`` environment
-    variable to ``ascii``::
+    Use this renderer by default by setting the ``PYRTL_RENDERER`` environment variable
+    to ``ascii``::
 
-        export PYRTL_RENDERER=ascii
+        $ export PYRTL_RENDERER=ascii
 
     .. image:: ../docs/screenshots/pyrtl-renderer-demo-ascii.png
        :width: 25em
     """
 
     _tick = "|"
 
-    _up, _down = ",", "."
-    _low, _high = "_", "-"
+    _up, _down = "|", "|"
+    _low, _high = "_", " "
+
+    _prev_line_up, _prev_line_down = " ", " "
+    _prev_line_low, _prev_line_high = " ", "_"
 
     _x = "|"
     _zero_x = "|"

tests/test_simulation.py

@@ -186,7 +186,7 @@ def check_rendered_trace(self, expected, **kwargs):
         )
         buff = io.StringIO()
         sim.tracer.render_trace(file=buff, renderer=self.renderer, **kwargs)
-        self.assertEqual(buff.getvalue(), expected)
+        self.assertEqual(expected, buff.getvalue())
 
     def test_hex_trace(self):
         expected = (
@@ -195,8 +195,8 @@ def test_hex_trace(self):
             "a 0x1 |0x4 |0x9 |0xb |0xc\n"
             "  \n"
             "b 0x2 |0x17|0x2b|0x78|----\n"
-            "  \n"
-            "c ____,---------.____,----\n"
+            "       _________      ____\n"
+            "c ____|         |____|\n"
         )
         self.check_rendered_trace(expected)
 
@@ -207,8 +207,8 @@ def test_oct_trace(self):
             "a 0o1  |0o4  |0o11 |0o13 |0o14\n"
             "  \n"
             "b 0o2  |0o27 |0o53 |0o170|-----\n"
-            "  \n"
-            "c _____,-----------._____,-----\n"
+            "        ___________       _____\n"
+            "c _____|           |_____|\n"
         )
 
         self.check_rendered_trace(expected, repr_func=oct)
@@ -220,8 +220,8 @@ def test_bin_trace(self):
             "a 0b1      |0b100    |0b1001   |0b1011   |0b1100\n"
             "  \n"
             "b 0b10     |0b10111  |0b101011 |0b1111000|---------\n"
-            "  \n"
-            "c _________,-------------------._________,---------\n"
+            "            ___________________           _________\n"
+            "c _________|                   |_________|\n"
         )
 
         self.check_rendered_trace(expected, repr_func=bin)
@@ -233,8 +233,8 @@ def test_decimal_trace(self):
             "a 1  |4  |9  |11 |12\n"
             "  \n"
             "b 2  |23 |43 |120|---\n"
-            "  \n"
-            "c ___,-------.___,---\n"
+            "      _______     ___\n"
+            "c ___|       |___|\n"
         )
         self.check_rendered_trace(expected, repr_func=str)