Facile Grammar
Original by Alex Thornton
Revised by David G. Kay, Winter 2012

The start symbol is [program].

{
[program]
[statement] \n.\n
[statement] \n [program]
[statement] \n [program]
[statement] \n [program]
[statement] \n [program]
[statement] \n [program]
[statement] \n [program]
[statement] \n [program]
[statement] \n [program]
[statement] \n [program]
[statement] \n [program]
}
The first right-hand side ends the program with a dot.
The other right-hand side is copied many times to
influence how often it's selected.  (If they're chosen
at random, there are many chances to get the continuing
one and just one chance to get the program-ending one.)

{
[statement]
LET [sp] [variableName] [sp] [number] 
PRINT [sp] [variableName] 
GOTO [sp] [number]
ADD [sp] [variableName] [sp] [number] 
SUB [sp] [variableName] [sp] [number]  
MUL [sp] [variableName] [sp] [number] 
DIV [sp] [variableName] [sp] [number] 
IF [sp] [variableName] [sp] [comparisonOp] [sp] [number] [sp] THEN [sp] [number]
GOSUB [sp] [number] 
RETURN
INC [sp] [variableName] 
DEC [sp] [variableName] 
}

{
[variableName]
[letter]
[variableName] [alphanumeric-plus]
}

{
[letter]
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
}

{
[alphanumeric-plus]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[letter]
[digit]
[digit]
[variable-punct]
}


{
[digit]
0
1
2
3
4
5
6
7
8
9
}


{
[variable-punct]
-
_
=
+
*
&
$
#
@
!
.
,
?
/
}
Might as well allow more symbols than Python does.

{
[number]
[digit]
[digit] [number]
}

{
[comparisonOp]
<
>
<=
>=
=
<>
}

{
[sp]
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\x20
\t
\x20 [sp] 
\t [sp] 
}