Note keyboard bindings in README.rst... (#91)

Add preamble to (tempoary?) asy file written to disk

Author: rocky

README.rst

@@ -1,4 +1,4 @@
-|CI status| |Pypi Installs| |Latest Version| |Supported Python Versions|
+|CI status| |PyPI Installs| |Latest Version| |Supported Python Versions|
 
 |Packaging status|
 
@@ -18,7 +18,7 @@ Features
    - limited ESC keyboard input; for example *esc* ``p`` *esc* is π
 * Syntax highlighting using `mathics-pygments <https://pypi.org/project/mathics-pygments/>`_ which includes dynamically created variables and functions.
 * Automatic detection of light or dark `terminal background color <https://pypi.org/project/term-background/>`_.
-* Optional Graphics rendering via `matplotlib <https://matplotlib.org/>`_ for 2D graphics, and `Asymptote <https://asymptote.sourceforge.io>`_ for 3D graphcs.
+* Optional Graphics rendering via `matplotlib <https://matplotlib.org/>`_ for 2D graphics, and `Asymptote <https://asymptote.sourceforge.io>`_ for 3D and 2D graphics.
 * Entering and displaying Unicode symbols such as used for Pi or Rule arrows
 * Provision for running in non-interactive batch mode which an be used inside POSIX shells
 
@@ -94,6 +94,35 @@ Feeding this into ``mathicsscript``:
 For a full list of options, type ``mathicsscript --help``.
 
 
+Asymptote key bindings
+----------------------
+
+In asymptote graphs keyboard bindings are (copied from the asymptote
+doc under `8.29 three
+<https://asymptote.sourceforge.io/doc/three.html#index-keyboard-bindings_003a>`_::
+
+    h: home
+    f: toggle fitscreen
+    x: spin about the X axis
+    y: spin about the Y axis
+    z: spin about the Z axis
+    s: stop spinning
+    m: rendering mode (solid/patch/mesh)
+    e: export
+    c: show camera parameters
+    p: play animation
+    r: reverse animation
+    : step animation
+    +: expand
+    =: expand
+    >: expand
+    -: shrink
+    _: shrink
+    <: shrink
+    q: exit
+    Ctrl-q: exit
+
+
 Why not IPython via Jupyter?
 ----------------------------
 
@@ -114,7 +143,7 @@ the core Mathic3 package.
 .. |screenshot| image:: https://mathics.org/images/mathicsscript1.gif
 .. |Latest Version| image:: https://badge.fury.io/py/mathicsscript.svg
 		 :target: https://badge.fury.io/py/mathicsscript
-.. |Pypi Installs| image:: https://pepy.tech/badge/mathicsscript
+.. |PyPI Installs| image:: https://pepy.tech/badge/mathicsscript
 .. |Supported Python Versions| image:: https://img.shields.io/pypi/pyversions/mathicsscript.svg
 .. |CI status| image:: https://github.com/Mathics3/mathicsscript/workflows/mathicsscript%20(ubuntu)/badge.svg
 		       :target: https://github.com/Mathics3/mathicsscript/actions

mathicsscript/asymptote.py

@@ -12,7 +12,12 @@
 from tempfile import NamedTemporaryFile
 from typing import Optional
 
-asy_program = os.environ.get("ASY_PROG", "asy")
+# An aysmptote string to
+INTEACTIVE_PREAMBLE = """
+// Generated by Mathics3 mathicsscript.
+"""
+
+ASY_PROGRAM = os.environ.get("ASY_PROG", "asy")
 
 # Add asymptote directory to AYMPTOTE_DIR
 asymptote_dir = os.environ.get("ASYMPTOTE_DIR", "")
@@ -23,7 +28,7 @@
 asymptote_version: Optional[str] = None
 try:
     result = run(
-        [asy_program, "--version"],
+        [ASY_PROGRAM, "--version"],
         timeout=0.5,
         stdout=PIPE,
         stderr=PIPE,
@@ -46,10 +51,10 @@ def get_srcdir():
 asy_config = os.path.join(mydir, "config.asy")
 
 
-class Asy(object):
+class Asy:
     def __init__(self, show_help=True):
         self.session = Popen(
-            [asy_program, f"-config={asy_config}", "-quiet", "-inpipe=0", "-outpipe=2"],
+            [ASY_PROGRAM, f"-config={asy_config}", "-quiet", "-inpipe=0", "-outpipe=2"],
             stdin=PIPE,
         )
         if show_help:
@@ -103,8 +108,8 @@ def write_asy_and_view(asy_string: str):
     with NamedTemporaryFile(
         mode="w", prefix="Mathics3-Graph-", suffix=".asy", delete=False
     ) as asy_fp:
-        asy_fp.write(asy_string + "\n")
-    subprocess.run(args=[asy_program, "-View", asy_fp.name])
+        asy_fp.write(INTEACTIVE_PREAMBLE + asy_string + "\n")
+    subprocess.run(args=[ASY_PROGRAM, "-View", asy_fp.name])
 
 
 if __name__ == "__main__":