feat: support nil keyword

Change-Id: I5e7155ae170853ce34f6492f9703915b5be70369

README.md

@@ -105,11 +105,10 @@ NOTE: **The `exprName` under the same struct field cannot be the same！**
 
 |Operator or Expression example|Explain|
 |-----|---------|
-|`true`|bool "true"|
-|`false`|bool "false"|
-|`1`|float64 "1"|
-|`1.0`|float64 "1.0"|
-|`'S'`|String "S"|
+|`true` `false`|bool|
+|`0` `0.0`|float64 "0"|
+|`''`|String|
+|`nil`|nil|
 |`+`|Digital addition or string splicing|
 |`-`|Digital subtraction or negative|
 |`*`|Digital multiplication|
@@ -146,7 +145,7 @@ NOTE: **The `exprName` under the same struct field cannot be the same！**
 |`>>`|Integer bitwise `shift right`| -->
 
 Operator priority(high -> low):
-* `()` `bool` `string` `float64` `!`
+* `()` `bool` `string` `float64` `nil` `!`
 * `*` `/` `%`
 * `+` `-`
 * `<` `<=` `>` `>=`

expr.go

@@ -66,6 +66,9 @@ func (p *Expr) parseOperand(expr *string) (e ExprNode) {
 	if e = readBoolExprNode(expr); e != nil {
 		return e
 	}
+	if e = readNilExprNode(expr); e != nil {
+		return e
+	}
 	return nil
 }
 
@@ -176,7 +179,7 @@ func (p *Expr) checkSyntax() error {
 
 /**
  * Priority:
- * () bool string float64 !
+ * () bool string float64 nil !
  * * / %
  * + -
  * < <= > >=

spec_operand.go

@@ -69,7 +69,7 @@ type boolExprNode struct {
 	val bool
 }
 
-var boolRegexp = regexp.MustCompile(`^!*(true|false)([\|&!= \t]{1}|$)`)
+var boolRegexp = regexp.MustCompile(`^!*(true|false)([\)\],\|&!= \t]{1}|$)`)
 
 func readBoolExprNode(expr *string) ExprNode {
 	s := boolRegexp.FindString(*expr)
@@ -121,7 +121,7 @@ type digitalExprNode struct {
 	val float64
 }
 
-var digitalRegexp = regexp.MustCompile(`^[\+\-]?\d+(\.\d+)?([\+\-\*\/%><\|&!=\^ \t\\]|$)`)
+var digitalRegexp = regexp.MustCompile(`^[\+\-]?\d+(\.\d+)?([\)\],\+\-\*\/%><\|&!=\^ \t\\]|$)`)
 
 func readDigitalExprNode(expr *string) ExprNode {
 	s := digitalRegexp.FindString(*expr)
@@ -170,3 +170,21 @@ func readPairedSymbol(p *string, left, right rune) *string {
 	}
 	return nil
 }
+
+type nilExprNode struct {
+	exprBackground
+}
+
+var nilRegexp = regexp.MustCompile(`^nil([\)\],\|&!= \t]{1}|$)`)
+
+func readNilExprNode(expr *string) ExprNode {
+	s := nilRegexp.FindString(*expr)
+	if s == "" {
+		return nil
+	}
+	*expr = (*expr)[3:]
+	e := &nilExprNode{}
+	return e
+}
+
+func (*nilExprNode) Run(currField string, tagExpr *TagExpr) interface{} { return nil }

spec_operator.go

@@ -108,6 +108,8 @@ func (ee *equalExprNode) Run(currField string, tagExpr *TagExpr) interface{} {
 		var r1 bool
 		r1, _ = v1.(bool)
 		return r == r1
+	case nil:
+		return v1 == nil
 	default:
 		return false
 	}

spec_selector.go

@@ -49,7 +49,7 @@ func (p *Expr) readSelectorExprNode(expr *string) ExprNode {
 	return operand
 }
 
-var selectorRegexp = regexp.MustCompile(`^(\!*)(\([ \t]*[A-Za-z_]+[A-Za-z0-9_\.]*[ \t]*\))?(\$)([\[\+\-\*\/%><\|&!=\^ \t\\]|$)`)
+var selectorRegexp = regexp.MustCompile(`^(\!*)(\([ \t]*[A-Za-z_]+[A-Za-z0-9_\.]*[ \t]*\))?(\$)([\)\[\],\+\-\*\/%><\|&!=\^ \t\\]|$)`)
 
 func findSelector(expr *string) (field string, name string, subSelector []string, boolPrefix *bool, found bool) {
 	raw := *expr

tagexpr.go

@@ -197,7 +197,11 @@ func (f *Field) setFloatGetter(kind reflect.Kind, ptrDeep int) {
 		}
 	} else {
 		f.valueGetter = func(ptr uintptr) interface{} {
-			return getFloat64(kind, f.newFrom(ptr, ptrDeep).UnsafeAddr())
+			v := f.newFrom(ptr, ptrDeep)
+			if v.CanAddr() {
+				return getFloat64(kind, v.UnsafeAddr())
+			}
+			return nil
 		}
 	}
 }
@@ -209,7 +213,11 @@ func (f *Field) setBoolGetter(ptrDeep int) {
 		}
 	} else {
 		f.valueGetter = func(ptr uintptr) interface{} {
-			return f.newFrom(ptr, ptrDeep).Bool()
+			v := f.newFrom(ptr, ptrDeep)
+			if v.IsValid() {
+				return v.Bool()
+			}
+			return nil
 		}
 	}
 }
@@ -221,7 +229,11 @@ func (f *Field) setStringGetter(ptrDeep int) {
 		}
 	} else {
 		f.valueGetter = func(ptr uintptr) interface{} {
-			return f.newFrom(ptr, ptrDeep).String()
+			v := f.newFrom(ptr, ptrDeep)
+			if v.IsValid() {
+				return v.String()
+			}
+			return nil
 		}
 	}
 }
@@ -405,6 +417,9 @@ func (t *TagExpr) getValue(field string, subFields []interface{}) (v interface{}
 		return nil
 	}
 	v = f.valueGetter(t.ptr)
+	if v == nil {
+		return nil
+	}
 	if len(subFields) == 0 {
 		return v
 	}
@@ -439,7 +454,7 @@ func (t *TagExpr) getValue(field string, subFields []interface{}) (v interface{}
 	}
 	switch vv.Kind() {
 	default:
-		if vv.CanInterface() {
+		if !vv.IsNil() && vv.CanInterface() {
 			return vv.Interface()
 		}
 		return nil

tagexpr_test.go

@@ -83,6 +83,7 @@ func Test(t *testing.T) {
 	d := "ddd"
 	e := new(int)
 	*e = 3
+	type iface interface{}
 	var cases = []struct {
 		tagName   string
 		structure interface{}
@@ -101,6 +102,8 @@ func Test(t *testing.T) {
 				g  string         `tagexpr:"{x:regexp('g\\d{3}$',$)}{y:regexp('g\\d{3}$')}"`
 				h  []string       `tagexpr:"{x:$[1]}{y:$[10]}"`
 				i  map[string]int `tagexpr:"{x:$['a']}{y:$[0]}"`
+				j  iface          `tagexpr:"$==1"`
+				k  *iface         `tagexpr:"$"`
 			}{
 				A:  5.0,
 				A2: 5.0,
@@ -129,6 +132,8 @@ func Test(t *testing.T) {
 				"h@y":   nil,
 				"i@x":   7.0,
 				"i@y":   nil,
+				"j@":    false,
+				"k@":    nil,
 			},
 		},
 		{
@@ -150,9 +155,12 @@ func Test(t *testing.T) {
 					s []string
 					m map[string][]string
 				} `tagexpr:"$['h']"`
-				i string `tagexpr:"(g.s)$[0]+(g.m)$['0'][0]==$"`
-				j bool   `tagexpr:"!$"`
-				k int    `tagexpr:"!$"`
+				i string  `tagexpr:"(g.s)$[0]+(g.m)$['0'][0]==$"`
+				j bool    `tagexpr:"!$"`
+				k int     `tagexpr:"!$"`
+				m *int    `tagexpr:"$==nil"`
+				n *bool   `tagexpr:"$==nil"`
+				p *string `tagexpr:"$"`
 			}{
 				A: 5.0,
 				b: "x",
@@ -177,6 +185,9 @@ func Test(t *testing.T) {
 				"i@":    true,
 				"j@":    true,
 				"k@":    nil,
+				"m@":    true,
+				"n@":    true,
+				"p@":    nil,
 			},
 		},
 	}

validator/README.md

@@ -105,11 +105,10 @@ type T struct {
 
 |Operator or Expression example|Explain|
 |-----|---------|
-|`true`|bool "true"|
-|`false`|bool "false"|
-|`1`|float64 "1"|
-|`1.0`|float64 "1.0"|
-|`'S'`|String "S"|
+|`true` `false`|bool|
+|`0` `0.0`|float64 "0"|
+|`''`|String|
+|`nil`|nil|
 |`+`|Digital addition or string splicing|
 |`-`|Digital subtraction or negative|
 |`*`|Digital multiplication|
@@ -146,7 +145,7 @@ type T struct {
 |`>>`|Integer bitwise `shift right`| -->
 
 Operator priority(high -> low):
-* `()` `bool` `string` `float64` `!`
+* `()` `bool` `string` `float64` `nil` `!`
 * `*` `/` `%`
 * `+` `-`
 * `<` `<=` `>` `>=`