func TestEval(t *testing.T) {
env := environment.New(nil)
environment.Define(env, &types.Symbol{"everything"}, &types.Number{42})
environment.Define(env, &types.Symbol{"cows"}, &types.String{"moo"})
environment.Define(env, &types.Symbol{"sheep"}, &types.String{"baa"})
environment.Define(env, &types.Symbol{"+"}, &types.Builtin{add})
if r, _ := Eval(env, &types.Symbol{"everything"}); !types.Eqv(r, &types.Number{42}) {
t.Error("Var 'everything' != 42: ", r)
}
f, _ := parser.Parse(strings.NewReader("(+ 1 1)"))
if r, err := Eval(env, f); err != nil {
t.Error("Evaluating (+ 1 1) caused an error: ", err)
} else if !types.Eqv(r, &types.Number{2}) {
t.Error("(+ 1 1) != 2: ", r)
}
f, _ = parser.Parse(strings.NewReader("(+ 1 (+ 2 3))"))
if r, err := Eval(env, f); err != nil {
t.Error("Evaluating (+ 1 (+ 2 3)) caused an error: ", err)
} else if !types.Eqv(r, &types.Number{6}) {
t.Error("(+ 1 (+ 2 3)) != 6: ", r)
}
}
func TestScoping(t *testing.T) {
env := environment.New(nil)
environment.Define(env, &types.Symbol{"begin"}, &types.Builtin{begin})
environment.Define(env, &types.Symbol{"+"}, &types.Builtin{add})
funcString := "(begin (define a 0) (define get-num ((lambda (a b) (define c 4) (lambda (b) (+ a b c))) 1 2)))"
f, err := parser.Parse(strings.NewReader(funcString))
if err != nil {
t.Error("Parsing funcString failed:", err)
}
if _, err := Eval(env, f); err != nil {
t.Error("Evaluating funcString failed:", err)
}
f, _ = parser.Parse(strings.NewReader("a"))
if a, err := Eval(env, f); err != nil {
t.Error("Evaluating 'a' failed:", err)
} else if !types.Eqv(a, &types.Number{0}) {
t.Error("a != 0", a)
}
f, _ = parser.Parse(strings.NewReader("(get-num 8)"))
if a, err := Eval(env, f); err != nil {
t.Error("Evaluating (get-num) failed:", err)
} else if !types.Eqv(a, &types.Number{13}) {
t.Error("(get-num 8) != 13:", a)
}
}
func TestEnv(t *testing.T) {
e1 := New(nil)
Define(e1, &types.Symbol{"cows"}, &types.String{"moo"})
Define(e1, &types.Symbol{"sheep"}, &types.String{"baa"})
e2 := New(e1)
Define(e2, &types.Symbol{"chickens"}, &types.String{"bawk"})
Define(e2, &types.Symbol{"sheep"}, &types.String{"meh"})
if r, _ := Get(e2, &types.Symbol{"sheep"}); !types.Eqv(r, &types.String{"meh"}) {
t.Error("Sheep in e2 do not say 'meh'")
}
if r, _ := Get(e1, &types.Symbol{"sheep"}); !types.Eqv(r, &types.String{"baa"}) {
t.Error("Sheep in e1 do not say 'baa': ", r.(*types.String).Value)
}
Define(e2, &types.Symbol{"sheep"}, &types.String{"baa"})
if r, _ := Get(e2, &types.Symbol{"sheep"}); !types.Eqv(r, &types.String{"baa"}) {
t.Error("Sheep in e2 do not say 'baa': ", r.(*types.String).Value)
}
}
func TestLambda(t *testing.T) {
env := environment.New(nil)
environment.Define(env, &types.Symbol{"+"}, &types.Builtin{add})
environment.Define(env, &types.Symbol{"begin"}, &types.Builtin{begin})
f, _ := parser.Parse(strings.NewReader("(lambda (n) n)"))
if a, err := Eval(env, f); err != nil {
t.Error("Evaluating lambda failed:", err, f)
} else if !types.IsSFunction(a) {
t.Error("Evaluating lambda didn't return an SFunction:", a)
}
f, _ = parser.Parse(strings.NewReader("(define add1 (lambda (n) (+ 1 n)))"))
if _, err := Eval(env, f); err != nil {
t.Error("Evaluating define lambda failed:", err)
}
if a, err := environment.Get(env, &types.Symbol{"add1"}); err != nil {
t.Error("'Get'ting add1 caused an error: ", err)
} else if !types.IsSFunction(a) {
t.Error("add1 is not an SFunction:", a)
}
f, _ = parser.Parse(strings.NewReader("(add1 1)"))
if a, err := Eval(env, f); err != nil {
t.Error("Evaluating (add1 1) failed:", err)
} else if !types.Eqv(a, &types.Number{2}) {
t.Error("(add1 1) != 2", a)
}
}
func Get(env *Environment, sym *types.Symbol) (types.Type, error) {
for e := env; e != nil; e = e.parent {
for v := e.env; v != nil; {
testSym, err := types.Caar(v)
if err != nil {
return nil, &envError{fmt.Sprintf("Checking for %s", sym.Value), err}
}
if types.Eqv(sym, testSym) {
if r, err := types.Cdar(v); err != nil {
return nil, &envError{fmt.Sprintf("Checking for %s", sym.Value), err}
} else {
return r, nil
}
}
nextV, _ := types.Cdr(v)
var ok bool
v, ok = nextV.(*types.Pair)
if !ok {
return nil, &envError{m: "Corrupt environment!!!"}
}
}
}
return nil, &envError{m: fmt.Sprintf("Unknown variable: %s", sym.Value)}
}
func TestIf(t *testing.T) {
env := environment.New(nil)
f, _ := parser.Parse(strings.NewReader("(if #t 'yes 'no)"))
if a, err := Eval(env, f); err != nil {
t.Error("Evaluating (if #t 'yes 'no) failed:", err)
} else if !types.Eqv(a, &types.Symbol{"yes"}) {
t.Error("result != yes", a)
}
f, _ = parser.Parse(strings.NewReader("(if #f 'yes 'no)"))
if a, err := Eval(env, f); err != nil {
t.Error("Evaluating (if #f 'yes 'no) failed:", err)
} else if !types.Eqv(a, &types.Symbol{"no"}) {
t.Error("result != no", a)
}
}
func TestQuote(t *testing.T) {
env := environment.New(nil)
f, _ := parser.Parse(strings.NewReader("(quote moo)"))
if a, err := Eval(env, f); err != nil {
t.Error("Evaluating (quote moo) failed:", err)
} else if !types.Eqv(a, &types.Symbol{"moo"}) {
t.Error("(quote moo) != moo", a)
}
}
func eqv(env interface{}, args t.Type) (t.Type, error) {
first, _ := t.Car(args)
for args, _ := t.Cdr(args); args != nil; args, _ = t.Cdr(args) {
arg, _ := t.Car(args)
if !t.Eqv(first, arg) {
return &t.Bool{false}, nil
}
}
return &t.Bool{true}, nil
}
func TestDefine(t *testing.T) {
env := environment.New(nil)
f, _ := parser.Parse(strings.NewReader("(define answer 42)"))
if _, err := Eval(env, f); err != nil {
t.Error("Evaluating (define answer 42) failed:", err)
}
if a, err := environment.Get(env, &types.Symbol{"answer"}); err != nil {
t.Error("'Get'ting 'answer' caused an error: ", err)
} else if !types.Eqv(a, &types.Number{42}) {
t.Error("answer != 42", a)
}
}
func TestBegin(t *testing.T) {
env := environment.New(nil)
environment.Define(env, &types.Symbol{"cows"}, &types.String{"moo"})
environment.Define(env, &types.Symbol{"sheep"}, &types.String{"baa"})
environment.Define(env, &types.Symbol{"begin"}, &types.Builtin{begin})
f, _ := parser.Parse(strings.NewReader("(begin cows sheep)"))
if r, err := Eval(env, f); err != nil {
t.Error("Evaluating (begin cows sheep) caused an error: ", err)
} else if !types.Eqv(r, &types.String{"baa"}) {
t.Error("(begin cows sheep) != baa", r)
}
}
func TestParser(t *testing.T) {
r, err := Parse(strings.NewReader("sym"))
if err != nil {
t.Error(err)
} else if !types.Eqv(r, &types.Symbol{"sym"}) {
t.Error("Expecting symbol, got", r)
}
str := "(moo (said the many) cows)"
r, err = Parse(strings.NewReader(str))
if err != nil {
t.Error(err)
} else if r.String() != str {
t.Error("expected", str, "got", r)
}
str = "(moo (cows"
r, err = Parse(strings.NewReader(str))
if err == nil {
t.Error("Expected parser error, got", r)
}
str = "(\"moo\" said the cows)"
r, err = Parse(strings.NewReader(str))
if err != nil {
t.Error(err)
} else if r.String() != str {
t.Error("expected", str, "got", r)
}
str = "'(moo ())"
expected := "(quote (moo #nil))"
r, err = Parse(strings.NewReader(str))
if err != nil {
t.Error(err)
} else if r.String() != expected {
t.Error("expected", expected, "got", r)
}
str = "(+ 1 1)"
expected = "(+ 1 1)"
r, err = Parse(strings.NewReader(str))
if err != nil {
t.Error(err)
} else if r.String() != expected {
t.Error("expected", expected, "got", r)
}
}
func equal_Number(env interface{}, args t.Type) (t.Type, error) {
arg, _ := t.Car(args)
first, ok := arg.(*t.Number)
if !ok {
return nil, fmt.Errorf("=: Not a number: %s", arg)
}
for args, _ := t.Cdr(args); args != nil; args, _ = t.Cdr(args) {
arg, _ := t.Car(args)
if !t.Eqv(first, arg) {
return &t.Bool{false}, nil
}
}
return &t.Bool{true}, nil
}
func TestFibonacci(t *testing.T) {
env := BuildEnvironment()
const funcString = "(define fib (lambda (a b max) (if (= 0 max) b (fib b (+ a b) (- max 1)))))"
f, err := parser.Parse(strings.NewReader(funcString))
if err != nil {
t.Error("Parsing funcString failed:", err)
}
if _, err := Eval(env, f); err != nil {
t.Error("Evaluating funcString failed:", err)
}
const funcString2 = "(fib 0 1 10)"
f, _ = parser.Parse(strings.NewReader(funcString2))
if a, err := Eval(env, f); err != nil {
t.Error("Evaluating", funcString2, "failed:", err)
} else if !types.Eqv(a, &types.Number{89}) {
t.Error(funcString2, "!= 89", a)
}
}