Logic interpreter

Latest on Hackage:0.1.2

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BSD3 licensed by Cameron Brandon White


Logic interpreter and parsing library


cabal update
cabal install WeberLogic


$ ./WeberLogic
Enter Command
> truthTable: a&b+c->~a&b
'a'   'b'   'c'   | (((a&b)+c)->(~a&b))
True  True  True  | False
True  True  False | False
True  False True  | False
True  False False | True 
False True  True  | True 
False True  False | True 
False False True  | False
False False False | True 

Enter Command
> toNand: a&b->c 

Enter Command
> toNor: a&b->c


The library contains two modules.

  1. WeberLogic.Parser
  2. WeberLogic.Actions


The WeberLogic.Parser provides functions which read stings and return an abstract syntax tree (AST). The AST in implement with a data type called LogicExp and Letter.

  • Data Types
    • LogicExp - A recursively defined data type which implements as abstract syntax tree. It provides the following type constructors which function as nodes in the AST: Not, And, Or, Implies, Iff, Nand, and Nor. The Predicate type constructor functions as the AST leaves.

    > import WeberLogic.Parser
    > Predicate 'A' [(Variable 'x', Name 'a')]
    > Not (Predicate 'A' [(Variable 'x', Name 'a')])
    > And (Predicate 'A' [(Variable 'x', Name 'a')]) (Predicate 'B' [])
    • Letter - This Data Constructor provies two Type constructors Variable and Name. They are used in the construction of Predicate which requires a list of type Letter

    > import WeberLogic.Parser
    > Predicate 'A' [(Variable 'x', Name 'a')]
  • Functions
    • parseExp

    > import WeberLogic.Parser
    > a = parseExp "Axa"
    > b = parseExp "~Axa"
    > c = parseExp "Axa&B"
    • parseArg

    > import WeberLogic.Parser
    > a = parseExp "|- Axa"
    > b = parseExp "~Axa, B |- Cax"
    > c = parseExp "Axa&B, B, C |- Ax->By"


The WeberLogic.Actions modules provides functions which manipulate the LogicExp AST.

> import WeberLogic.Parser
> import WeberLogic.Actions

> mapM_ putStrLn $ truthTableStr $ readExp "A&B"
'a'   'b'   | (a&~b)
True  True  | False
True  False | True 
False True  | False
False False | False

> toNand $ readExp "A&~B" 

> toNor $ readExp "A&~B" 
Depends on 2 packages:
Used by 1 package:
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