1 // Licensed to the Apache Software Foundation (ASF) under one
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9 //   http://www.apache.org/licenses/LICENSE-2.0
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15 // specific language governing permissions and limitations
16 // under the License.
17 
18 //! Variable provider
19 
20 use crate::error::Result;
21 use crate::scalar::ScalarValue;
22 
23 /// Variable type, system/user defined
24 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
25 pub enum VarType {
26     /// System variable, like @@version
27     System,
28     /// User defined variable, like @name
29     UserDefined,
30 }
31 
32 /// A var provider for @variable
33 pub trait VarProvider {
34     /// Get variable value
get_value(&self, var_names: Vec<String>) -> Result<ScalarValue>35     fn get_value(&self, var_names: Vec<String>) -> Result<ScalarValue>;
36 }
37