Rebuild docs with Python 3 and Sphinx 3.0.2.

docs/with_sympy.md

@@ -1,4 +1,3 @@
-
 # Symbolic Evaluation with SymPy
 
 
@@ -553,6 +552,11 @@ We can already generate:
 
 This is pretty old stuff...  (E.g. from 1999, M. Anton Ertl [Compilation of Stack-Based Languages](http://www.complang.tuwien.ac.at/projects/rafts.html) he goes a lot further for Forth.)
 
+
+```python
+
+```
+
 ## "A Transformation Based Approach to Semantics-Directed Code Generation"
 
 by Arthur Nunes-Harwitt
@@ -1204,6 +1208,11 @@ eval(hylomorphism([])(5)(lambda n: n == 0)(lambda n: (n-1, n-1)))(lambda a: lamb
 ```
 
 
+```python
+
+```
+
+
 ```python
 hylomorphism(0)([1, 2, 3])(lambda n: not n)(lambda n: (n[0], n[1:]))
 ```
@@ -1219,6 +1228,21 @@ eval(hylomorphism([])([1, 2, 3])(lambda n: not n)(lambda n: (n[1:], n[1:])))(lam
 ```
 
 
+```python
+
+```
+
+
+```python
+
+```
+
+
+```python
+
+```
+
+
 ```python
 def hylomorphism(c):
     return lambda a: lambda P: (