slowly getting cleaner

eval.go

@@ -2,10 +2,8 @@ package main
 
 import (
 	"bufio"
-	"errors"
 	"fmt"
 	"io"
-	"reflect"
 )
 
 func eval(v interface{}, env *environment) (interface{}, error) {
@@ -14,40 +12,10 @@ func eval(v interface{}, env *environment) (interface{}, error) {
 	}
 
 	switch t := v.(type) {
-
 	case symbol:
-		debugPrint("eval symbol")
-		s, err := env.get(t)
-		if err != nil {
-			return nil, err
-		}
-		return eval(s, env)
-
+		return t.eval(env)
 	case *sexp:
-		debugPrint("eval sexp")
-		if t.len() == 0 {
-			return nil, errors.New("illegal evaluation of empty sexp ()")
-		}
-
-		if t.quotelvl > 0 {
-			return t, nil
-		}
-
-		// eval the first item
-		v, err := eval(t.items[0], env)
-		if err != nil {
-			return nil, err
-		}
-
-		c, ok := v.(callable)
-		if !ok {
-			return nil, fmt.Errorf(`expected special form or builtin procedure, received %v`, reflect.TypeOf(v))
-		}
-		if len(t.items) > 1 {
-			return c.call(env, t.items[1:])
-		}
-		return c.call(env, nil)
-
+		return t.eval(env)
 	default:
 		debugPrint("default eval")
 		return v, nil
@@ -83,7 +51,6 @@ func (i interpreter) run(env *environment) {
 		v, err := parse(i.tokens)
 		switch err {
 		case io.EOF:
-			fmt.Println("EOF lol")
 			return
 		case nil:
 			i.eval(v, env)

skeam.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"reflect"
 	"strconv"
 	"strings"
 )
@@ -17,6 +18,32 @@ type sexp struct {
 	quotelvl int
 }
 
+func (s *sexp) eval(env *environment) (interface{}, error) {
+	debugPrint("eval sexp")
+	if s.len() == 0 {
+		return nil, errors.New("illegal evaluation of empty sexp ()")
+	}
+
+	if s.quotelvl > 0 {
+		return s, nil
+	}
+
+	// eval the first item
+	v, err := eval(s.items[0], env)
+	if err != nil {
+		return nil, err
+	}
+
+	c, ok := v.(callable)
+	if !ok {
+		return nil, fmt.Errorf(`expected special form or builtin procedure, received %v`, reflect.TypeOf(v))
+	}
+	if len(s.items) > 1 {
+		return c.call(env, s.items[1:])
+	}
+	return c.call(env, nil)
+}
+
 type callable interface {
 	call(*environment, []interface{}) (interface{}, error)
 }
@@ -46,6 +73,15 @@ func (s sexp) len() int {
 
 type symbol string
 
+func (s symbol) eval(env *environment) (interface{}, error) {
+	debugPrint("eval symbol")
+	v, err := env.get(s)
+	if err != nil {
+		return nil, err
+	}
+	return eval(v, env)
+}
+
 var universe = &environment{map[symbol]interface{}{
 	// predefined values
 	"#t":   true,