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dust/src/abstract_tree/assignment.rs

115 lines
3.9 KiB
Rust

use serde::{Deserialize, Serialize};
use tree_sitter::Node;
use crate::{AbstractTree, Error, Identifier, Map, Result, Statement, Type, TypeDefintion, Value};
#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
pub struct Assignment {
identifier: Identifier,
type_definition: Option<TypeDefintion>,
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, context: &Map) -> Result<Self> {
Error::expect_syntax_node(source, "assignment", node)?;
let identifier_node = node.child_by_field_name("identifier").unwrap();
let identifier = Identifier::from_syntax_node(source, identifier_node, context)?;
let type_node = node.child_by_field_name("type");
let type_definition = if let Some(type_node) = type_node {
Some(TypeDefintion::from_syntax_node(source, type_node, context)?)
} else {
None
};
let operator_node = node
.child_by_field_name("assignment_operator")
.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_by_field_name("statement").unwrap();
let statement = Statement::from_syntax_node(source, statement_node, context)?;
if let Some(type_defintion) = &type_definition {
let statement_type = statement.expected_type(context)?;
if type_defintion.r#type() != &statement_type {
return Err(Error::TypeCheck {
expected: type_defintion.r#type().clone(),
actual: statement_type,
location: node.start_position(),
source: source[node.byte_range()].to_string(),
});
}
}
Ok(Assignment {
identifier,
type_definition,
operator,
statement,
})
}
fn run(&self, source: &str, context: &Map) -> Result<Value> {
let key = self.identifier.inner();
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 {
return Err(Error::VariableIdentifierNotFound(key.clone()));
}
}
AssignmentOperator::MinusEqual => {
if let Some(mut previous_value) = context.variables()?.get(key).cloned() {
previous_value -= value;
previous_value
} else {
return Err(Error::VariableIdentifierNotFound(key.clone()));
}
}
AssignmentOperator::Equal => value,
};
if let Some(type_definition) = &self.type_definition {
type_definition.check(&new_value, context)?;
}
context.variables_mut()?.insert(key.clone(), new_value);
Ok(Value::Empty)
}
fn expected_type(&self, _context: &Map) -> Result<Type> {
Ok(Type::Empty)
}
}