Add tilde (like) operator (#2)

README.md

@@ -155,11 +155,12 @@ period_months < 4
 
 ### Field expression operators
 
-| Operator             | Meaning       | Supported types              |
-|----------------------|---------------|------------------------------|
-| `:` or `=`           | Equal, one of | `int64`, `float64`, `string` |
-| `!=` or `!:`         | Not equal     | `int64`, `float64`, `string` |
-| `>`, `>=`, `<`, `<=` | Comparison    | `int64`, `float64`           |
+| Operator             | Meaning                       | Supported types              |
+|----------------------|-------------------------------|------------------------------|
+| `:` or `=`           | Equal, one of                 | `int64`, `float64`, `string` |
+| `!=` or `!:`         | Not equal                     | `int64`, `float64`, `string` |
+| `~`                  | “Like” or “contains” operator | `string`                     |
+| `>`, `>=`, `<`, `<=` | Comparison                    | `int64`, `float64`           |
 
 
 ### Boolean operators

dumbql.go

@@ -39,7 +39,7 @@
 //	SingleCharEscape    <- ["\\/bfnrt]
 //	UnicodeEscape       <- 'u' HexDigit HexDigit HexDigit HexDigit
 //	HexDigit            <- [0-9a-f]i
-//	CmpOp               <- ( ">=" / ">" / "<=" / "<" / "!:" / "!=" / ":" / "=" )
+//	CmpOp               <- ( ">=" / ">" / "<=" / "<" / "!:" / "!=" / ":" / "=" / "~" )
 //	OneOfExpr           <- '[' _ values:(OneOfValues)? _ ']'
 //	OneOfValues         <- head:OneOfValue tail:(_ ',' _ OneOfValue)*
 //	_                   <- [ \t\r\n]*
@@ -58,11 +58,12 @@
 //
 // # Field expression operators
 //
-//	| Operator             | Meaning       | Supported types              |
-//	|----------------------|---------------|------------------------------|
-//	| `:` or `=`           | Equal, one of | `int64`, `float64`, `string` |
-//	| `!=` or `!:`         | Not equal     | `int64`, `float64`, `string` |
-//	| `>`, `>=`, `<`, `<=` | Comparison    | `int64`, `float64`           |
+//	| Operator             | Meaning                       | Supported types              |
+//	|----------------------|-------------------------------|------------------------------|
+//	| `:` or `=`           | Equal, one of                 | `int64`, `float64`, `string` |
+//	| `!=` or `!:`         | Not equal                     | `int64`, `float64`, `string` |
+//	| `~`                  | “Like” or “contains” operator | `string`                     |
+//	| `>`, `>=`, `<`, `<=` | Comparison                    | `int64`, `float64`           |
 //
 // # Boolean operators
 //

query/ast.go

@@ -122,6 +122,7 @@ const (
 	GreaterThanOrEqual
 	LessThan
 	LessThanOrEqual
+	Like
 )
 
 func (c FieldOperator) String() string {
@@ -138,6 +139,8 @@ func (c FieldOperator) String() string {
 		return "<"
 	case LessThanOrEqual:
 		return "<="
+	case Like:
+		return "~"
 	default:
 		return "unknown!"
 	}

query/grammar.peg

@@ -27,7 +27,7 @@ EscapeSequence      <- SingleCharEscape / UnicodeEscape
 SingleCharEscape    <- ["\\/bfnrt]
 UnicodeEscape       <- 'u' HexDigit HexDigit HexDigit HexDigit
 HexDigit            <- [0-9a-f]i
-CmpOp               <- ( ">=" / ">" / "<=" / "<" / "!:" / "!=" / ":" / "=" )
+CmpOp               <- ( ">=" / ">" / "<=" / "<" / "!:" / "!=" / ":" / "=" / "~" )
 OneOfExpr           <- '[' _ values:(OneOfValues)? _ ']'                     { return parseOneOfExpression(values) }
 OneOfValues         <- head:OneOfValue tail:(_ ',' _ OneOfValue)*            { return parseOneOfValues(head, tail) }
 _                   <- [ \t\r\n]*

query/parser_helpers.go

@@ -30,6 +30,8 @@ func resolveFieldOperator(op any) (FieldOperator, error) {
 		return NotEqual, nil
 	case ":", "=":
 		return Equal, nil
+	case "~":
+		return Like, nil
 	default:
 		return 0, fmt.Errorf("unknown compare operator %q", op)
 	}

query/sql.go

@@ -44,6 +44,8 @@ func (f *FieldExpr) ToSql() (string, []any, error) { //nolint:revive
 		sqlizer = sq.Lt{field: value}
 	case LessThanOrEqual:
 		sqlizer = sq.LtOrEq{field: value}
+	case Like:
+		sqlizer = sq.Like{field: value}
 	default:
 		return "", nil, fmt.Errorf("unknown operator %q", f.Op)
 	}

query/sql_test.go

@@ -81,6 +81,13 @@ func TestToSql(t *testing.T) { //nolint:funlen
 			want:     "SELECT * FROM dummy_table WHERE NOT (status = ? AND eps < ?)",
 			wantArgs: []any{int64(200), 0.003},
 		},
+		{
+			input: `name~"John"`,
+			want:  "SELECT * FROM dummy_table WHERE name LIKE ?",
+			wantArgs: []any{
+				"John",
+			},
+		},
 	}
 
 	for _, test := range tests {