A few code cleanups as suggested by staticcheck

This commits adds in a few suggestions that I got from staticcheck. I also cleaned up a bit further in some cases.

/home/jacob/Downloads/gval/evaluable.go
  (300, 25)  SA1012  do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use
  (332, 25)  SA1012  do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use

/home/jacob/Downloads/gval/language.go
  (258, 2)  SA6003  should range over string, not []rune(string)

/home/jacob/Downloads/gval/operator.go
  (107, 2)  S1023  redundant return statement

/home/jacob/Downloads/gval/parse.go
  (123, 3)  S1005  unnecessary assignment to the blank identifier

/home/jacob/Downloads/gval/parser.go
  (22, 46)  S1023  redundant return statement
  (84, 2)   S1023  redundant return statement

/home/jacob/Downloads/gval/random_test.go
  (16, 2)   U1000  var empty3 is unused
  (105, 2)  U1000  var panics is unused

evaluable.go

@@ -297,7 +297,7 @@ func regEx(a, b Evaluable) (Evaluable, error) {
  return matched, err
  }, nil
  }
- s, err := b.EvalString(nil, nil)
+ s, err := b.EvalString(context.TODO(), nil)
  if err != nil {
  return nil, err
  }
@@ -329,7 +329,7 @@ func notRegEx(a, b Evaluable) (Evaluable, error) {
  return !matched, err
  }, nil
  }
- s, err := b.EvalString(nil, nil)
+ s, err := b.EvalString(context.TODO(), nil)
  if err != nil {
  return nil, err
  }

language.go

@@ -254,8 +254,7 @@ func (l *Language) makePrefixKey(key string) interface{} {
 }
 
 func (l *Language) makeInfixKey(key string) string {
- runes := []rune(key)
- for _, r := range runes {
+ for _, r := range key {
  l.operatorSymbols[r] = struct{}{}
  }
  return key

operator.go

@@ -104,7 +104,6 @@ func (op *infix) initiate(name string) {
  return f(a, b)
  }, nil
  }
- return
 }
 
 type opFunc func(a, b interface{}) (interface{}, error)

parse.go

@@ -120,8 +120,7 @@ func (p *Parser) parseOperator(c context.Context, stack *stageStack, eval Evalua
  p.Camouflage("operator")
  return stage{Evaluable: eval}, nil
  }
- operator, _ := p.operators[op]
- switch operator := operator.(type) {
+ switch operator := p.operators[op].(type) {
  case *infix:
  return stage{
  Evaluable: eval,

parser.go

@@ -19,7 +19,7 @@ type Parser struct {
 func newParser(expression string, l Language) *Parser {
  sc := scanner.Scanner{}
  sc.Init(strings.NewReader(expression))
- sc.Error = func(*scanner.Scanner, string) { return }
+ sc.Error = func(*scanner.Scanner, string) {}
  sc.Filename = expression + "\t"
  p := &Parser{scanner: sc, Language: l}
  p.resetScannerProperties()
@@ -81,7 +81,6 @@ func (p *Parser) Camouflage(unit string, expected ...rune) {
  panic(fmt.Errorf("can only Camouflage() after Scan(): %v", p.camouflage))
  }
  p.camouflage = p.Expected(unit, expected...)
- return
 }
 
 // Peek returns the next Unicode character in the source without advancing

random_test.go

@@ -13,7 +13,6 @@ var (
  hello = "hello"
  empty struct{}
  empty2 *string
- empty3 *int
 
  values = []interface{}{
  -1,
@@ -101,13 +100,9 @@ var (
  "\n",
  "\000",
  }
-
- panics = 0
 )
 
-const (
- SEED = 1487873697990155515
-)
+const SEED = 1487873697990155515
 
 func BenchmarkRandom(bench *testing.B) {
  rand.Seed(SEED)