Make cannot deal with spaces in filenames.

Is make wrong, or is it your filename?

docs/Advent_of_Code_2017_December_6th.md

@@ -0,0 +1,267 @@
+
+# Advent of Code 2017
+
+## December 6th
+
+
+    [0 2 7 0] dup max
+
+
+
+```python
+from notebook_preamble import D, J, V, define
+```
+
+
+```python
+J('[0 2 7 0] dup max')
+```
+
+    [0 2 7 0] 7
+
+
+
+```python
+from joy.library import SimpleFunctionWrapper
+from joy.utils.stack import list_to_stack
+
+
+@SimpleFunctionWrapper
+def index_of(stack):
+    '''Given a sequence and a item, return the index of the item, or -1 if not found.
+
+    E.g.:
+
+       [a b c] a index_of
+    ------------------------
+               0
+
+       [a b c] d index_of
+    ------------------------
+            -1
+
+    '''
+    item, (sequence, stack) = stack
+    i = 0
+    while sequence:
+        term, sequence = sequence
+        if term == item:
+            break
+        i += 1
+    else:
+        i = -1
+    return i, stack
+
+
+D['index_of'] = index_of
+```
+
+
+```python
+J('[0 2 7 0] 7 index_of')
+```
+
+    2
+
+
+
+```python
+J('[0 2 7 0] 23 index_of')
+```
+
+    -1
+
+
+Starting at `index` distribute `count` "blocks" to the "banks" in the sequence.
+
+    [...] count index distribute
+    ----------------------------
+               [...]
+
+This seems like it would be a PITA to implement in Joypy...
+
+
+```python
+from joy.utils.stack import iter_stack, list_to_stack
+
+
+@SimpleFunctionWrapper
+def distribute(stack):
+    '''Starting at index+1 distribute count "blocks" to the "banks" in the sequence.
+
+    [...] count index distribute
+    ----------------------------
+               [...]
+
+    '''
+    index, (count, (sequence, stack)) = stack
+    assert count >= 0
+    cheat = list(iter_stack(sequence))
+    n = len(cheat)
+    assert index < n
+    cheat[index] = 0
+    while count:
+        index += 1
+        index %= n
+        cheat[index] += 1
+        count -= 1
+    return list_to_stack(cheat), stack
+
+
+D['distribute'] = distribute
+```
+
+
+```python
+J('[0 2 7 0] dup max [index_of] nullary distribute')
+```
+
+    [2 4 1 2]
+
+
+
+```python
+J('[2 4 1 2] dup max [index_of] nullary distribute')
+```
+
+    [3 1 2 3]
+
+
+
+```python
+J('[3 1 2 3] dup max [index_of] nullary distribute')
+```
+
+    [0 2 3 4]
+
+
+
+```python
+J('[0 2 3 4] dup max [index_of] nullary distribute')
+```
+
+    [1 3 4 1]
+
+
+
+```python
+J('[1 3 4 1] dup max [index_of] nullary distribute')
+```
+
+    [2 4 1 2]
+
+
+### Recalling "Generator Programs"
+
+    [a F] x
+    [a F] a F 
+    
+    [a F] a swap [C] dip rest cons
+    a   [a F]    [C] dip rest cons
+    a C [a F]            rest cons
+    a C   [F]                 cons
+
+    w/ C == dup G
+
+    a dup G [F] cons
+    a a   G [F] cons
+
+    w/ G == dup max [index_of] nullary distribute
+
+
+```python
+define('direco == dip rest cons')
+```
+
+
+```python
+define('G == [direco] cons [swap] swoncat cons')
+```
+
+
+```python
+define('make_distributor == [dup dup max [index_of] nullary distribute] G')
+```
+
+
+```python
+J('[0 2 7 0] make_distributor 6 [x] times pop')
+```
+
+    [0 2 7 0] [2 4 1 2] [3 1 2 3] [0 2 3 4] [1 3 4 1] [2 4 1 2]
+
+
+### A function to drive a generator and count how many states before a repeat.
+First draft:
+
+    [] [GEN] x [pop index_of 0 >=] [pop size --] [[swons] dip x] primrec
+
+(?)
+
+    []       [GEN] x [pop index_of 0 >=] [pop size --] [[swons] dip x] primrec
+    [] [...] [GEN]   [pop index_of 0 >=] [pop size --] [[swons] dip x] primrec
+    [] [...] [GEN]    pop index_of 0 >=
+    [] [...]              index_of 0 >=
+                                -1 0 >=
+                                 False
+
+Base case
+
+    [] [...] [GEN] [pop index_of 0 >=] [pop size --] [[swons] dip x] primrec
+    [] [...] [GEN]                      pop size --
+    [] [...]                                size --
+    [] [...]                                size --
+
+A mistake, `popop` and no need for `--`
+
+    [] [...] [GEN] popop size
+    []                   size
+    n
+
+Recursive case
+
+    [] [...] [GEN] [pop index_of 0 >=] [popop size] [[swons] dip x] primrec
+    [] [...] [GEN]                                   [swons] dip x  F
+    [] [...] swons [GEN]                                         x  F
+    [[...]]        [GEN]                                         x  F
+    [[...]] [...]  [GEN]                                            F
+
+    [[...]] [...] [GEN] F
+
+What have we learned?
+
+    F == [pop index_of 0 >=] [popop size] [[swons] dip x] primrec
+
+
+```python
+define('count_states == [] swap x [pop index_of 0 >=] [popop size] [[swons] dip x] primrec')
+```
+
+
+```python
+define('AoC2017.6 == make_distributor count_states')
+```
+
+
+```python
+J('[0 2 7 0] AoC2017.6')
+```
+
+    5
+
+
+
+```python
+J('[1 1 1] AoC2017.6')
+```
+
+    4
+
+
+
+```python
+J('[8 0 0 0 0 0] AoC2017.6')
+```
+
+    15
+