use serde::{Deserialize, Serialize}; use tree_sitter::Node; use crate::{AbstractTree, Error, Identifier, Map, Result, Statement, Value}; #[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)] pub struct Assignment { identifier: Identifier, operator: AssignmentOperator, statement: Statement, } #[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)] pub enum AssignmentOperator { Equal, PlusEqual, MinusEqual, } impl AbstractTree for Assignment { fn from_syntax_node(source: &str, node: Node) -> Result { Error::expect_syntax_node(source, "assignment", node)?; let identifier_node = node.child(0).unwrap(); let identifier = Identifier::from_syntax_node(source, identifier_node)?; let operator_node = node.child(1).unwrap().child(0).unwrap(); let operator = match operator_node.kind() { "=" => AssignmentOperator::Equal, "+=" => AssignmentOperator::PlusEqual, "-=" => AssignmentOperator::MinusEqual, _ => { return Err(Error::UnexpectedSyntaxNode { expected: "=, += or -=", actual: operator_node.kind(), location: operator_node.start_position(), relevant_source: source[operator_node.byte_range()].to_string(), }) } }; let statement_node = node.child(2).unwrap(); let statement = Statement::from_syntax_node(source, statement_node)?; Ok(Assignment { identifier, operator, statement, }) } fn run(&self, source: &str, context: &mut Map) -> Result { let key = self.identifier.inner().clone(); let value = self.statement.run(source, context)?; let new_value = match self.operator { AssignmentOperator::PlusEqual => { if let Some(mut previous_value) = context.variables()?.get(&key).cloned() { previous_value += value; previous_value } else { Value::Empty } } AssignmentOperator::MinusEqual => { if let Some(mut previous_value) = context.variables()?.get(&key).cloned() { previous_value -= value; previous_value } else { Value::Empty } } AssignmentOperator::Equal => value, }; context.variables_mut()?.insert(key, new_value); Ok(Value::Empty) } }