fix: staticcheck and deadcode findings repo-wide, modernize counting loops

parser/parser.go

@@ -210,18 +210,17 @@ func (p *state) parseText(line []token.Token) {
 		rest = rest[1:]
 	}
 
-	// Frame: $number ; optional args: -number.
+	// Frame: $number ; optional args: -number.  Whatever remains after the
+	// header is the body and is parsed by the caller.
 	if len(rest) > 0 && rest[0].Kind == token.Dollar {
 		text.Frame = parseOperand(rest[:2]) // "$" "number"
-		rest = rest[2:]
-		if len(rest) >= 2 && rest[0].Kind == token.Minus && rest[1].Kind == token.Number {
+		if len(rest) >= 4 && rest[2].Kind == token.Minus && rest[3].Kind == token.Number {
 			text.Args = &ast.Operand{
 				Kind: ast.OpImmediate,
-				Imm:  ast.Immediate{Val: parseInt(rest[1].Text), HasVal: true},
-				Raw:  "-" + rest[1].Text,
-				Pos:  rest[0].Pos,
+				Imm:  ast.Immediate{Val: parseInt(rest[3].Text), HasVal: true},
+				Raw:  "-" + rest[3].Text,
+				Pos:  rest[2].Pos,
 			}
-			rest = rest[2:]
 		}
 	}
 
@@ -387,10 +386,8 @@ func parseImmediate(g []token.Token) ast.Immediate {
 		} else {
 			imm.Float = text
 		}
-		i++
 	} else if i < len(g) && (g[i].Kind == token.String || g[i].Kind == token.Rune) {
 		imm.Str = g[i].Text
-		i++
 	}
 	return imm
 }