Use the doctest module in get_example_data (#308)

Fixes #282 

Still several todos here:

- [x] Clean up code (probably don't need to define the class inside of
the function)
- [ ] Add tests
- [ ] Check that the generated JSON is as desired (the execution status
is not actually included. I'm not clear why)
- [ ] Make it so that any doctest anywhere is run, not just ones in
"Examples" (this doesn't necessarily need to be done in this PR)
- [ ] Allow libraries to configure doctest options (like ELLIPSIS)

Here's an example:

```py
def docstring(x):
    """
    Examples
    ========

    >>> from test_mod import docstring
    >>> a = docstring(1)
    >>> a
    2

    >>> 1 + a
    3

    >>> import matplotlib.pyplot as plt
    >>> plt.plot([0, 1], [0, 1])
    >>> plt.show()

    >>> 1 + 1
    2

    >>> syntax error

    >>> 1/0 # exception
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    ZeroDivisionError: division by zero

    >>> 1/0 # unexpected exception
    """
    return x + 1

__version__ = '0'
```

```toml
[global]
module = 'test_mod'
```

Generates

```json
  "example_section_data": {
    "children": [
      {
        "type": "code",
        "value": "from test_mod import docstring\n"
      },
      {
        "type": "code",
        "value": "a = docstring(1)\n"
      },
      {
        "type": "code",
        "value": "a\n"
      },
      {
        "type": "code",
        "value": "1 + a\n"
      },
      {
        "type": "code",
        "value": "import matplotlib.pyplot as plt\n"
      },
      {
        "type": "code",
        "value": "plt.plot([0, 1], [0, 1])\n"
      },
      {
        "type": "code",
        "value": "plt.show()\n"
      },
      {
        "type": "Fig",
        "value": {
          "kind": "assets",
          "module": "test_mod",
          "path": "fig-test_mod:docstring-0-c8430bd5.png",
          "type": "RefInfo",
          "version": "0"
        }
      },
      {
        "type": "code",
        "value": "1 + 1\n"
      },
      {
        "type": "code",
        "value": "syntax error\n"
      },
      {
        "type": "code",
        "value": "1/0 # exception\n"
      },
      {
        "type": "code",
        "value": "1/0 # unexpected exception\n"
      }
    ],
```

examples/IPython.toml

@@ -3,7 +3,7 @@ module = 'IPython'
 logo = "img/ipython-logo.png"
 exec_failure = "fallback"
 docs_path = "~/dev/IPython/docs/source"
-exec = true
+execute_doctests = true
 execute_exclude_patterns = [
    'IPython.lib.display:Audio',
    'IPython.core.display_functions:display'

examples/dask.toml

@@ -41,3 +41,4 @@ exclude = [ "dask.utils:Dispatch",
 
 #docs_path = "~/dev/dask/docs/source"
 exec_failure = 'fallback'
+execute_doctests = false

examples/distributed.toml

@@ -17,6 +17,7 @@ exclude = [
     "distributed.shuffle._comms:CommShardsBuffer",
 ] #docs_path = "~/dev/dask/docs/source"
 exec_failure = 'fallback'
+execute_doctests = false
 
 [global.expected_errors]
 NumpydocParseError = [

examples/matplotlib.toml

@@ -91,7 +91,7 @@ examples_exclude = [
 "lines_bars_and_markers/marker_reference.py",
 "lines_bars_and_markers/multivariate_marker_plot.py",
 ]
-exec = true
+execute_doctests = true
 
 [global.expected_errors]
 IncorrectInternalDocsLen = [

examples/networkx.toml

@@ -6,7 +6,7 @@ submodules = []
 
 # docs_path = '~/dev/numpy/doc/source'
 
-exec = true
+execute_doctests = true
 exclude_jedi = ['networkx.algorithms.planarity.PlanarEmbedding']
 exec_failure = 'fallback'
 source = 'https://github.com/networkx/networkx'

examples/numpy.toml

@@ -9,6 +9,7 @@ exclude = [
 ]
 
 execute_exclude_patterns = [
+    'numpy:set_numeric_ops',
     'numpy._',
     'numpy.testing._priv',
     'numpy.errstate',
@@ -62,7 +63,7 @@ submodules = [
 
 docs_path = '~/dev/numpy/doc/source'
 
-exec = true
+execute_doctests = true
 narrative_exclude = [
    'doc/source/reference/arrays.ndarray.rst',
    'doc/source/user/how-to-how-to.rst',

examples/pandas.toml

@@ -5,6 +5,7 @@ exec_failure = "fallback"
 submodules = []
 exclude = [""
 ]
+execute_doctests = false
 [pandas.expected_errors]
 IncorrectInternalDocsLen = [
    "pandas.core.indexes.period:PeriodIndex.asof_locs",
@@ -43,3 +44,6 @@ WrongTypeAtField = [
    "pandas.core.resample:Resampler.interpolate",
    "pandas.core.generic:NDFrame.to_pickle",
 ]
+
+[global.implied_imports]
+pd = 'pandas'

examples/papyri.toml

@@ -4,7 +4,7 @@ submodules = ['examples']
 examples_folder = '~/dev/papyri/docs/examples/'
 logo = "../papyri-logo.png"
 docs_path = "~/dev/papyri/docs"
-exec = true
+execute_doctests = true
 exec_failure = 'raise'
 exclude= ["papyri.utils:FullQual","papyri.utils:Cannonical" ]
 [global.directives]

examples/scipy.toml

@@ -1,7 +1,7 @@
 [global]
 module = 'scipy'
 logo = "img/scipy_logo.png"
-exec = true
+execute_doctests = true
 submodules = [ "signal","misc"]
 exclude = [
     # OTHER.

examples/xarray.toml

@@ -5,7 +5,7 @@ execute_exclude_patterns = []
 submodules = []
 
 
-exec = true
+execute_doctests = true
 exclude = [
 ]
 exec_failure = 'fallback'

papyri/examples.py

@@ -226,13 +226,13 @@ async def example1(
     Examples
     --------
     >>> import matplotlib.pyplot as plt
-    ... fig, ax = plt.subplots()
-    ... ax.plot(range(10))
+    >>> fig, ax = plt.subplots()
+    >>> ax.plot(range(10))
 
     And now
 
     >>> ax.plot(range(5, 15))
-    ... plt.show()
+    >>> plt.show()
 
     """
     return "ok"
@@ -243,24 +243,24 @@ def example2():
     Examples
     --------
     >>> import numpy as np
-    ... import matplotlib.pyplot as plt
-    ... from scipy.interpolate import UnivariateSpline
+    >>> import matplotlib.pyplot as plt
+    >>> from scipy.interpolate import UnivariateSpline
 
     >>> x = np.linspace(-3, 3, 50)
-    ... y = np.exp(-(x ** 2)) + 0.1 * np.random.randn(50)
-    ... plt.plot(x, y, "ro", ms=5)
+    >>> y = np.exp(-(x ** 2)) + 0.1 * np.random.randn(50)
+    >>> plt.plot(x, y, "ro", ms=5)
 
     Use the default value for the smoothing parameter:
 
     >>> spl = UnivariateSpline(x, y)
-    ... xs = np.linspace(-3, 3, 1000)
-    ... plt.plot(xs, spl(xs), "g", lw=3)
+    >>> xs = np.linspace(-3, 3, 1000)
+    >>> plt.plot(xs, spl(xs), "g", lw=3)
 
     Manually change the amount of smoothing:
 
     >>> spl.set_smoothing_factor(0.5)
-    ... plt.plot(xs, spl(xs), "b", lw=3)
-    ... plt.show()
+    >>> plt.plot(xs, spl(xs), "b", lw=3)
+    >>> plt.show()
 
     """
     pass