core: vm: sqlvm: check if a number is a valid address

This commit implements isAddress function to allow a number literal to
be considered as an address literal. Since Solidity only allows '0x' to
be written in lower case, we remove the handling of upper case '0X' to
keep the behavior in sync with Solidity.

In addition to isAddress implementation, this commit also removes
'String' methods from AST nodes to prevent them from implementing the
builtin 'Stringer' interface. Therefore, our AST printer is now able to
print struct fields of value nodes instead of only one string.

1 files changed, 9 insertions, 4 deletions

diff --git a/core/vm/sqlvm/parser/parser.go b/core/vm/sqlvm/parser/parser.go
index 5cfe9400e..fdde37dd5 100644
--- a/core/vm/sqlvm/parser/parser.go
+++ b/core/vm/sqlvm/parser/parser.go
@@ -8,6 +8,7 @@ import (
 	"strings"
 	"unicode/utf8"
 
+	"github.com/dexon-foundation/dexon/common"
 	"github.com/dexon-foundation/dexon/core/vm/sqlvm/ast"
 	"github.com/dexon-foundation/dexon/core/vm/sqlvm/errors"
 	"github.com/shopspring/decimal"
@@ -52,16 +53,20 @@ func assertExprSlice(x interface{}) []ast.ExprNode {
 	return es
 }
 
-// TODO(wmin0): finish it.
 func isAddress(h []byte) bool {
-	return false
+	ma, err := common.NewMixedcaseAddressFromString(string(h))
+	if err != nil {
+		return false
+	}
+	return ma.ValidChecksum()
 }
 
 func hexToInteger(h []byte) *ast.IntegerValueNode {
 	d := decimal.Zero
-	l := len(h)
+	x := h[2:]
+	l := len(x)
 	base := decimal.New(16, 0)
-	for idx, b := range h {
+	for idx, b := range x {
 		i, err := strconv.ParseInt(string([]byte{b}), 16, 32)
 		if err != nil {
 			panic(fmt.Sprintf("invalid hex digit %s: %v", []byte{b}, err))