Refactor and implement dumbql:"-" (omit) struct tag

README.md

@@ -29,6 +29,7 @@ Simple (dumb) query language and parser for Go.
 - One-of/In expressions (`occupation = [designer, "ux analyst"]`)
 - Schema validation
 - Drop-in usage with [squirrel](https://github.com/Masterminds/squirrel) query builder or SQL drivers directly
+- Struct matching with `dumbql` struct tag
 
 ## Examples
 
@@ -143,6 +144,7 @@ import (
   "fmt"
 
   "github.com/defer-panic/dumbql"
+  "github.com/defer-panic/dumbql/match"
   "github.com/defer-panic/dumbql/query"
 )
 
@@ -196,7 +198,7 @@ func main() {
   ast, _ := query.Parse("test", []byte(q))
   expr := ast.(query.Expr)
 
-  matcher := &query.DefaultMatcher{}
+  matcher := &match.StructMatcher{}
 
   filtered := make([]User, 0, len(users))
 

match/match_example_test.go

@@ -0,0 +1,73 @@
+package match_test
+
+import (
+	"fmt"
+
+	"github.com/defer-panic/dumbql/match"
+	"github.com/defer-panic/dumbql/query"
+)
+
+type MatchUser struct {
+	ID       int64   `dumbql:"id"`
+	Name     string  `dumbql:"name"`
+	Age      int64   `dumbql:"age"`
+	Score    float64 `dumbql:"score"`
+	Location string  `dumbql:"location"`
+	Role     string  `dumbql:"role"`
+}
+
+func Example() {
+	users := []MatchUser{
+		{
+			ID:       1,
+			Name:     "John Doe",
+			Age:      30,
+			Score:    4.5,
+			Location: "New York",
+			Role:     "admin",
+		},
+		{
+			ID:       2,
+			Name:     "Jane Smith",
+			Age:      25,
+			Score:    3.8,
+			Location: "Los Angeles",
+			Role:     "user",
+		},
+		{
+			ID:       3,
+			Name:     "Bob Johnson",
+			Age:      35,
+			Score:    4.2,
+			Location: "Chicago",
+			Role:     "user",
+		},
+		// This one will be dropped:
+		{
+			ID:       4,
+			Name:     "Alice Smith",
+			Age:      25,
+			Score:    3.8,
+			Location: "Los Angeles",
+			Role:     "admin",
+		},
+	}
+
+	q := `(age >= 30 and score > 4.0) or (location:"Los Angeles" and role:"user")`
+	ast, _ := query.Parse("test", []byte(q))
+	expr := ast.(query.Expr)
+
+	matcher := &match.StructMatcher{}
+
+	filtered := make([]MatchUser, 0, len(users))
+
+	for _, user := range users {
+		if expr.Match(&user, matcher) {
+			filtered = append(filtered, user)
+		}
+	}
+
+	fmt.Println(filtered)
+	// Output:
+	// [{1 John Doe 30 4.5 New York admin} {2 Jane Smith 25 3.8 Los Angeles user} {3 Bob Johnson 35 4.2 Chicago user}]
+}

match/struct.go

@@ -0,0 +1,67 @@
+package match
+
+import (
+	"reflect"
+
+	"github.com/defer-panic/dumbql/query"
+)
+
+// StructMatcher is a basic implementation of the Matcher interface for evaluating query expressions against structs.
+// It supports struct tags using the `dumbql` tag name, which allows you to specify a custom field name.
+type StructMatcher struct{}
+
+func (m *StructMatcher) MatchAnd(target any, left, right query.Expr) bool {
+	return left.Match(target, m) && right.Match(target, m)
+}
+
+func (m *StructMatcher) MatchOr(target any, left, right query.Expr) bool {
+	return left.Match(target, m) || right.Match(target, m)
+}
+
+func (m *StructMatcher) MatchNot(target any, expr query.Expr) bool {
+	return !expr.Match(target, m)
+}
+
+// MatchField matches a field in the target struct using the provided value and operator. It supports struct tags using
+// the `dumbql` tag name, which allows you to specify a custom field name. If struct tag is not provided, it will use
+// the field name as is.
+func (m *StructMatcher) MatchField(target any, field string, value query.Valuer, op query.FieldOperator) bool {
+	t := reflect.TypeOf(target)
+
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+
+	if t.Kind() != reflect.Struct {
+		return false
+	}
+
+	for i := 0; i < t.NumField(); i++ {
+		f := t.Field(i)
+
+		tag := f.Tag.Get("dumbql")
+		if tag == "-" {
+			return true // Field marked with dumbql:"-" always match (in other words does not affect the result)
+		}
+
+		fname := f.Name
+		if tag != "" {
+			fname = tag
+		}
+
+		if fname == field {
+			v := reflect.ValueOf(target)
+			if v.Kind() == reflect.Ptr {
+				v = v.Elem()
+			}
+
+			return m.MatchValue(v.Field(i).Interface(), value, op)
+		}
+	}
+
+	return true
+}
+
+func (m *StructMatcher) MatchValue(target any, value query.Valuer, op query.FieldOperator) bool {
+	return value.Match(target, op)
+}

match_example_test.go → match/struct_example_test.go

@@ -1,8 +1,9 @@
-package dumbql_test
+package match_test
 
 import (
 	"fmt"
 
+	"github.com/defer-panic/dumbql/match"
 	"github.com/defer-panic/dumbql/query"
 )
 
@@ -15,7 +16,7 @@ type User struct {
 	Role     string  `dumbql:"role"`
 }
 
-func Example_simpleMatching() {
+func ExampleStructMatcher_MatchField_simpleMatching() {
 	user := &User{
 		ID:       1,
 		Name:     "John Doe",
@@ -31,14 +32,14 @@ func Example_simpleMatching() {
 	expr := ast.(query.Expr)
 
 	// Create a matcher
-	matcher := &query.DefaultMatcher{}
+	matcher := &match.StructMatcher{}
 	result := expr.Match(user, matcher)
 
 	fmt.Printf("%s: %v\n", q, result)
 	// Output: name = "John Doe": true
 }
 
-func Example_complexMatching() {
+func ExampleStructMatcher_MatchField_complexMatching() {
 	user := &User{
 		ID:       1,
 		Name:     "John Doe",
@@ -54,14 +55,14 @@ func Example_complexMatching() {
 	expr := ast.(query.Expr)
 
 	// Create a matcher
-	matcher := &query.DefaultMatcher{}
+	matcher := &match.StructMatcher{}
 	result := expr.Match(user, matcher)
 
 	fmt.Printf("%s: %v\n", q, result)
 	// Output: age >= 25 and location:["New York", "Los Angeles"] and score > 4.0: true
 }
 
-func Example_numericComparisons() {
+func ExampleStructMatcher_MatchField_numericComparisons() {
 	user := &User{
 		ID:       1,
 		Name:     "John Doe",
@@ -81,7 +82,7 @@ func Example_numericComparisons() {
 		`score < 5.0`,
 	}
 
-	matcher := &query.DefaultMatcher{}
+	matcher := &match.StructMatcher{}
 
 	for _, q := range queries {
 		ast, _ := query.Parse("test", []byte(q))
@@ -97,7 +98,7 @@ func Example_numericComparisons() {
 	// Query 'score < 5.0' match result: true
 }
 
-func Example_stringOperations() {
+func ExampleStructMatcher_MatchField_stringOperations() {
 	user := &User{
 		ID:       1,
 		Name:     "John Doe",
@@ -115,7 +116,7 @@ func Example_stringOperations() {
 		`role:admin`,
 	}
 
-	matcher := &query.DefaultMatcher{}
+	matcher := &match.StructMatcher{}
 
 	for _, q := range queries {
 		ast, _ := query.Parse("test", []byte(q))
@@ -130,7 +131,7 @@ func Example_stringOperations() {
 	// Query 'role:admin' match result: true
 }
 
-func Example_notExpressions() {
+func ExampleStructMatcher_MatchField_notExpressions() {
 	user := &User{
 		ID:       1,
 		Name:     "John Doe",
@@ -147,7 +148,7 @@ func Example_notExpressions() {
 		`not (role:"user" and score < 3.0)`,
 	}
 
-	matcher := &query.DefaultMatcher{}
+	matcher := &match.StructMatcher{}
 
 	for _, q := range queries {
 		ast, _ := query.Parse("test", []byte(q))
@@ -161,7 +162,7 @@ func Example_notExpressions() {
 	// Query 'not (role:"user" and score < 3.0)' match result: true
 }
 
-func Example_multiMatch() {
+func ExampleStructMatcher_MatchField_multiMatch() {
 	users := []User{
 		{
 			ID:       1,
@@ -202,7 +203,7 @@ func Example_multiMatch() {
 	ast, _ := query.Parse("test", []byte(q))
 	expr := ast.(query.Expr)
 
-	matcher := &query.DefaultMatcher{}
+	matcher := &match.StructMatcher{}
 
 	filtered := make([]User, 0, len(users))
 
@@ -217,7 +218,7 @@ func Example_multiMatch() {
 	// [{1 John Doe 30 4.5 New York admin} {2 Jane Smith 25 3.8 Los Angeles user} {3 Bob Johnson 35 4.2 Chicago user}]
 }
 
-func Example_oneOfExpression() {
+func ExampleStructMatcher_MatchField_oneOfExpression() {
 	user := &User{
 		ID:       1,
 		Name:     "John Doe",
@@ -234,7 +235,7 @@ func Example_oneOfExpression() {
 		`age:[25, 30, 35]`,
 	}
 
-	matcher := &query.DefaultMatcher{}
+	matcher := &match.StructMatcher{}
 
 	for _, q := range queries {
 		ast, _ := query.Parse("test", []byte(q))
@@ -248,7 +249,7 @@ func Example_oneOfExpression() {
 	// Query 'age:[25, 30, 35]' match result: true
 }
 
-func Example_edgeCases() {
+func ExampleStructMatcher_MatchField_edgeCases() {
 	user := &User{
 		ID:       1,
 		Name:     "John Doe",
@@ -271,19 +272,65 @@ func Example_edgeCases() {
 		`(age > 20 and age < 40) and (score >= 4.0 or role:"admin")`,
 	}
 
-	matcher := &query.DefaultMatcher{}
+	matcher := &match.StructMatcher{}
 
 	for _, q := range queries {
 		ast, _ := query.Parse("test", []byte(q))
 		expr := ast.(query.Expr)
 		result := expr.Match(user, matcher)
 		fmt.Printf("Query '%s' match result: %v\n", q, result)
 	}
-
 	// Output:
-	// Query 'nonexistent:"value"' match result: false
+	// Query 'nonexistent:"value"' match result: true
 	// Query 'age:"not a number"' match result: false
 	// Query 'name:""' match result: false
 	// Query 'score:0' match result: false
 	// Query '(age > 20 and age < 40) and (score >= 4.0 or role:"admin")' match result: true
 }
+
+func ExampleStructMatcher_MatchField_structTagOmit() {
+	type User struct {
+		ID       int64   `dumbql:"id"`
+		Name     string  `dumbql:"name"`
+		Password string  `dumbql:"-"` // Omitted from querying
+		Internal bool    `dumbql:"-"` // Omitted from querying
+		Score    float64 `dumbql:"score"`
+	}
+
+	user := &User{
+		ID:       1,
+		Name:     "John",
+		Password: "secret123",
+		Internal: true,
+		Score:    4.5,
+	}
+
+	// Test various queries including omitted fields
+	queries := []string{
+		// Query against visible field
+		`id:1`,
+		// Query against omitted field - always matches
+		`password:"wrong_password"`,
+		// Query against omitted boolean field - always matches
+		`internal:false`,
+		// Combined visible and omitted fields
+		`id:1 and password:"wrong_password"`,
+		// Complex query with omitted fields
+		`(id:1 or score > 4.0) and (password:"wrong" or internal:false)`,
+	}
+
+	matcher := &match.StructMatcher{}
+
+	for _, q := range queries {
+		ast, _ := query.Parse("test", []byte(q))
+		expr := ast.(query.Expr)
+		result := expr.Match(user, matcher)
+		fmt.Printf("Query '%s' match result: %v\n", q, result)
+	}
+	// Output:
+	// Query 'id:1' match result: true
+	// Query 'password:"wrong_password"' match result: true
+	// Query 'internal:false' match result: true
+	// Query 'id:1 and password:"wrong_password"' match result: true
+	// Query '(id:1 or score > 4.0) and (password:"wrong" or internal:false)' match result: true
+}