parser location doesn't need to be in the context, does it?

eval.go

@@ -11,7 +11,6 @@ type Context struct {
 	Dictionary Dictionary
 	Stack      *Stack
 	RStack     *Stack
-	I          int // current parser location
 }
 
 // Eval evaulates a given line, recursively descending into given words as needed
@@ -22,30 +21,30 @@ func (c *Context) Eval(line string) error {
 	var comment bool
 	immediate := true
 
-	for c.I = 0; c.I < len(line); c.I = c.I + 1 {
-		switch line[c.I] {
+	for i := 0; i < len(line); i = i + 1 {
+		switch line[i] {
 		case '(', ')': // comments
 			if len(word) == 0 {
-				if line[c.I] == '(' {
+				if line[i] == '(' {
 					comment = true
 					continue
 				}
 				comment = false
 				continue
 			} else {
-				word = append(word, line[c.I])
+				word = append(word, line[i])
 			}
 		case ':', ';': // COMPILE/IMMEDIATE mode swapping
 			if len(word) == 0 {
-				if line[c.I] == ':' {
+				if line[i] == ':' {
 					immediate = false
-				} else if line[c.I-1] == ' ' && line[c.I] == ';' {
+				} else if line[i-1] == ' ' && line[i] == ';' {
 					c.Dictionary.AddWord(words[0], nil, words[1:])
 					word = []byte{}
 					immediate = true
 				}
 			} else {
-				word = append(word, line[c.I])
+				word = append(word, line[i])
 			}
 		case ' ':
 			if !immediate { // continue building our subroutine if we're not in immediate mode...
@@ -82,12 +81,12 @@ func (c *Context) Eval(line string) error {
 				word = []byte{}
 			} else if len(w.Source) != 0 {
 				// user-defined word; let's descend...
-				c.RStack.Push(c.I)
+				c.RStack.Push(i)
 				err := c.Eval(strings.Join(w.Source, " ") + " ")
 				if err != nil {
 					return err
 				}
-				c.I, err = c.RStack.Pop()
+				i, err = c.RStack.Pop()
 				if err != nil {
 					return fmt.Errorf("error while popping from return stack: %v", err)
 				}
@@ -95,7 +94,7 @@ func (c *Context) Eval(line string) error {
 			}
 		default:
 			if !comment {
-				word = append(word, line[c.I])
+				word = append(word, line[i])
 			}
 		}
 	}