PLCParser implemented in Hy ~language¶
See also:
- Propositional Logic Clause Parser main project hub
- Jupyter notebook with Calypso Hy kernel
Magics¶
Load extension for using magics on the document:
In [1]:
%load_ext hyPLCParser
#%reload_ext hyPLCParser
Use for example: %plc (1 and? 1) Operators available: nope? ¬ and? ∧ xor? ⊕ or? ∨ nand? ↑ nxor? ↔ nor? ↓ Operands available: True 1 ⊤ False 0 ⊥
Line magics¶
Prefix and infix support
In [2]:
%plc (1 and? 1)
Out[2]:
True
In [3]:
%plc (True ⊕ False ⊕ True ⊕ False ⊕ True)
Out[3]:
True
In [4]:
%plc ( ( ∧ 1 1 1 ) ∨ ( ∧ 1 1 0 ) )
Out[4]:
True
Cell magics¶
Prefix and infix support
In [6]:
%%plc
#$(1 and? (or? 0 1))
Out[6]:
True
Registering additional operators
In [7]:
%%plc
; register + sign for infix notation
#>+
; evaluate code
#$(1 + (2 + (3)))
Out[7]:
6
Adding more complex custom operators
In [8]:
%%plc
; use operator macro to add mean operator with custom symbol
(defoperator mean x̄ [&rest args]
(/ (sum args) (len args)))
; try prefix notation with nested structure
(print (x̄ 1 2 3 4))
(print (x̄ 1 2 (x̄ 3 4)))
; note that infix notation in cell magics needs to be prefixed with
; #$ reader macro marker while in line magics it is not required
(print #$(1 x̄ 2 x̄ 3 x̄ 4))
2.5 2.1666666666666665 3.125
Order of precedence¶
By default order of precedence is from left to right. Here we will use defoperators to define additional operators beyond logical ones. Then for variety we use defmixfix macro to evaluate clause. First evaluation will give 9 as an answer because evaluation is started from 1 + 2 and then that is multiplied
In [17]:
%%plc
(defoperators * +)
(print "First"
(defmixfix 1 + 2 * 3))
(defprecedence * +)
(print "Second"
(defmixfix 1 + 2 * 3))
First 9 Second 7
Mixing Hy and Python on same cell
In [9]:
# the first line is hy code supporting infix and prefix logical clauses
%plc ( 1 and? 1 or? (0) )
# the second line is python code. this is possible because above code is line magics
[a for a in (1, 2, 3)]
Out[9]:
True
Out[9]:
[1, 2, 3]
Normal Hy language support
In [10]:
%%plc
; just define a function ...
(defn f [x] (print x))
; ... and call it
(f 3.1416)
; cant use python code in plc cell magics!
3.1416
In [11]:
%%plc
; set up variables
(setv A True B True C True)
(setv clause "( A ∧ B ∧ C )")
; use variables on clause
(print clause "=" #$( A ∧ B ∧ C ))
( A ∧ B ∧ C ) = True