Implement IS_DEFINED function

parsers/nosql/nosql.peg

@@ -15,6 +15,8 @@ func makeSelectStmt(columns, table, whereClause interface{}, count interface{},
 		selectStmt.Filters = filters
 	} else if filters, ok := whereClause.(parsers.Constant); ok {
 		selectStmt.Filters = filters
+	} else if filters, ok := whereClause.(parsers.SelectItem); ok {
+		selectStmt.Filters = filters
 	}
 
 	if n, ok := count.(int); ok {
@@ -186,7 +188,7 @@ SelectProperty <- name:Identifier path:(DotFieldAccess / ArrayFieldAccess)* {
     return makeSelectItem(name, path, parsers.SelectItemTypeField)
 }
 
-SelectItem <- selectItem:(Literal / StringEqualsExpression / SelectArray / SelectObject / SelectProperty) asClause:AsClause? {
+SelectItem <- selectItem:(Literal / FunctionCall / SelectArray / SelectObject / SelectProperty) asClause:AsClause? {
     var itemResult parsers.SelectItem
     switch typedValue := selectItem.(type) {
     case parsers.SelectItem:
@@ -240,6 +242,7 @@ ComparisonExpression <- "(" ws ex:OrExpression ws ")" { return ex, nil }
     / left:SelectItem ws op:ComparisonOperator ws right:SelectItem {
     return parsers.ComparisonExpression{Left:left,Right:right,Operation:string(op.([]uint8))}, nil
 } / ex:BooleanLiteral { return ex, nil }
+  / ex:SelectItem { return ex, nil }
 
 OrderByClause <- OrderBy ws ex1:OrderExpression others:(ws "," ws ex:OrderExpression { return ex, nil })* {
     return makeOrderByClause(ex1, others)
@@ -303,10 +306,16 @@ BooleanLiteral <- ("true"i / "false"i) {
     return parsers.Constant{Type: parsers.ConstantTypeBoolean, Value: boolValue}, nil
 }
 
+FunctionCall <- StringEqualsExpression / IsDefined
+
 StringEqualsExpression <- StringEquals ws "(" ws ex1:SelectItem ws "," ws ex2:SelectItem ws ignoreCase:("," ws boolean:SelectItem { return boolean, nil })? ")" {
     return parsers.FunctionCall{Type: parsers.FunctionCallStringEquals, Arguments: []interface{}{ex1, ex2, ignoreCase}}, nil
 }
 
+IsDefined <- "IS_DEFINED"i ws "(" ws ex:SelectItem ws ")" {
+    return parsers.FunctionCall{Type: parsers.FunctionCallIsDefined, Arguments: []interface{}{ex}}, nil
+}
+
 Integer <- [0-9]+ {
     return strconv.Atoi(string(c.text))
 }

parsers/nosql/nosql_string_functions_test.go

@@ -8,7 +8,7 @@ import (
 
 func Test_Execute_StringFunctions(t *testing.T) {
 
-	t.Run("Should execute function STRINGEQUALS(ex1, ex2, ignoreCase)", func(t *testing.T) {
+	t.Run("Should parse function STRINGEQUALS(ex1, ex2, ignoreCase)", func(t *testing.T) {
 		testQueryParse(
 			t,
 			`SELECT STRINGEQUALS(c.id, "123", true) FROM c`,
@@ -46,7 +46,7 @@ func Test_Execute_StringFunctions(t *testing.T) {
 		)
 	})
 
-	t.Run("Should execute function STRINGEQUALS(ex1, ex2)", func(t *testing.T) {
+	t.Run("Should parse function STRINGEQUALS(ex1, ex2)", func(t *testing.T) {
 		testQueryParse(
 			t,
 			`SELECT STRINGEQUALS(c.id, "123") FROM c`,

parsers/nosql/nosql_type_checking_functions_test.go

@@ -0,0 +1,46 @@
+package nosql_test
+
+import (
+	"testing"
+
+	"github.com/pikami/cosmium/parsers"
+)
+
+func Test_Execute_TypeCheckingFunctions(t *testing.T) {
+
+	t.Run("Should parse function IS_DEFINED", func(t *testing.T) {
+		testQueryParse(
+			t,
+			`SELECT IS_DEFINED(c.id) FROM c WHERE IS_DEFINED(c.pk)`,
+			parsers.SelectStmt{
+				SelectItems: []parsers.SelectItem{
+					{
+						Type: parsers.SelectItemTypeFunctionCall,
+						Value: parsers.FunctionCall{
+							Type: parsers.FunctionCallIsDefined,
+							Arguments: []interface{}{
+								parsers.SelectItem{
+									Path: []string{"c", "id"},
+									Type: parsers.SelectItemTypeField,
+								},
+							},
+						},
+					},
+				},
+				Table: parsers.Table{Value: "c"},
+				Filters: parsers.SelectItem{
+					Type: parsers.SelectItemTypeFunctionCall,
+					Value: parsers.FunctionCall{
+						Type: parsers.FunctionCallIsDefined,
+						Arguments: []interface{}{
+							parsers.SelectItem{
+								Path: []string{"c", "pk"},
+								Type: parsers.SelectItemTypeField,
+							},
+						},
+					},
+				},
+			},
+		)
+	})
+}