Task: Truth table




Go: package main

import (
    "bufio"
    "errors"
    "fmt"
    "go/ast"
    "go/parser"
    "go/token"
    "os"
    "reflect"
)

func main() {
    in := bufio.NewScanner(os.Stdin)
    for {
        fmt.Print("Expr:  ")
        in.Scan()
        if err := in.Err(); err != nil {
            fmt.Println(err)
            return
        }
        if !tt(in.Text()) {
            return
        }
    }
}

func tt(expr string) bool {
    
    tree, err := parser.ParseExpr(expr)
    if err != nil {
        fmt.Println(err)
        return false
    }
    
    e := &evaluator{nil, map[string]bool{}, tree}
    
    
    ast.Walk(e, tree)
    
    for _, n := range e.names {
        fmt.Printf("%-6s", n)
    }
    fmt.Println(" ", expr)
    
    e.evalVar(0)
    return true
}

type evaluator struct {
    names []string        
    val   map[string]bool 
    tree  ast.Expr        
}



func (e *evaluator) Visit(n ast.Node) ast.Visitor {
    if id, ok := n.(*ast.Ident); ok {
        if !e.val[id.Name] {
            e.names = append(e.names, id.Name)
            e.val[id.Name] = true
        }
    }
    return e
}





func (e *evaluator) evalVar(nx int) bool {
    if nx == len(e.names) {
        
        v, err := evalNode(e.tree, e.val)
        if err != nil {
            fmt.Println(" ", err)
            return false
        }
        
        for _, n := range e.names {
            fmt.Printf("%-6t", e.val[n])
        }
        
        fmt.Println(" ", v)
        return true
    }
    
    for _, v := range []bool{false, true} {
        e.val[e.names[nx]] = v
        if !e.evalVar(nx + 1) {
            return false
        }
    }
    return true
}


func evalNode(nd ast.Node, val map[string]bool) (bool, error) {
    switch n := nd.(type) {
    case *ast.Ident:
        return val[n.Name], nil
    case *ast.BinaryExpr:
        x, err := evalNode(n.X, val)
        if err != nil {
            return false, err
        }
        y, err := evalNode(n.Y, val)
        if err != nil {
            return false, err
        }
        switch n.Op {
        case token.AND:
            return x && y, nil
        case token.OR:
            return x || y, nil
        case token.XOR:
            return x != y, nil
        default:
            return unsup(n.Op)
        }
    case *ast.UnaryExpr:
        x, err := evalNode(n.X, val)
        if err != nil {
            return false, err
        }
        switch n.Op {
        case token.XOR:
            return !x, nil
        default:
            return unsup(n.Op)
        }
    case *ast.ParenExpr:
        return evalNode(n.X, val)
    }
    return unsup(reflect.TypeOf(nd))
}

func unsup(i interface{}) (bool, error) {
    return false, errors.New(fmt.Sprintf("%v unsupported", i))
}




Python: from itertools import product

while True:
    bexp = input('\nBoolean expression: ')
    bexp = bexp.strip()
    if not bexp:
        print("\nThank you")
        break
    code = compile(bexp, '<string>', 'eval')
    names = code.co_names
    print('\n' + ' '.join(names), ':', bexp)
    for values in product(range(2), repeat=len(names)):
        env = dict(zip(names, values))
        print(' '.join(str(v) for v in values), ':', eval(code, env))