test: add example

.golangci.yaml

@@ -61,6 +61,7 @@ linters-settings:
         allow:
           - $gostd
           - github.com/stretchr/testify
+          - github.com/laojianzi/kql-go
 
   funlen:
     ignore-comments: true

README.md

@@ -17,15 +17,17 @@ import (
     "github.com/laojianzi/kql-go/parser"
 )
 
-query := `service_name: "redis" OR service_name: "mysql" AND level: "error" AND start_time > 1723286863 AND latency >= 1.5`
+query := `service_name: "redis" OR service_name: "mysql" AND level: "error" and start_time > 1723286863 anD latency >= 1.5`
 // Parse query into AST
 stmt, err := parser.New(query).Stmt()
 if err != nil {
-    return nil, err
+    panic(err)
 }
 
 // output AST to KQL query
 fmt.Println(stmt.String())
+// output:
+// service_name: "redis" OR service_name: "mysql" AND level: "error" AND start_time > 1723286863 AND latency >= 1.5
 ```
 
 ## Contact us

parser/ast.go

@@ -62,7 +62,11 @@ func (e *MatchExpr) String() string {
 
 	if e.Field != "" {
 		buf.WriteString(e.Field)
-		buf.WriteByte(' ')
+
+		if e.Operator != TokenKindOperatorEql {
+			buf.WriteByte(' ')
+		}
+
 		buf.WriteString(e.Operator.String())
 		buf.WriteByte(' ')
 	}

parser/parser_example_test.go

@@ -0,0 +1,21 @@
+package parser_test
+
+import (
+	"fmt"
+
+	"github.com/laojianzi/kql-go/parser"
+)
+
+func Example() {
+	query := `service_name: "redis" OR service_name: "mysql" AND level: "error" and start_time > 1723286863 anD latency >= 1.5`
+	// Parse query into AST
+	stmt, err := parser.New(query).Stmt()
+	if err != nil {
+		panic(err)
+	}
+
+	// output AST to KQL query
+	fmt.Println(stmt.String())
+	// output:
+	// service_name: "redis" OR service_name: "mysql" AND level: "error" AND start_time > 1723286863 AND latency >= 1.5
+}