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dust/src/abstract_tree/block.rs
2024-03-08 12:24:11 -05:00

80 lines
2.1 KiB
Rust

use crate::{
context::Context,
error::{RuntimeError, ValidationError},
Value,
};
use super::{AbstractTree, Action, Statement, Type};
#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
pub struct Block<'src> {
statements: Vec<Statement<'src>>,
}
impl<'src> Block<'src> {
pub fn new(statements: Vec<Statement<'src>>) -> Self {
Self { statements }
}
}
impl<'src> AbstractTree for Block<'src> {
fn expected_type(&self, _context: &Context) -> Result<Type, ValidationError> {
let final_statement = self.statements.last().unwrap();
final_statement.expected_type(_context)
}
fn validate(&self, _context: &Context) -> Result<(), ValidationError> {
for statement in &self.statements {
statement.validate(_context)?;
}
Ok(())
}
fn run(self, _context: &Context) -> Result<Action, RuntimeError> {
let mut previous = Value::none();
for statement in self.statements {
let action = statement.run(_context)?;
previous = match action {
Action::Return(value) => value,
r#break => return Ok(r#break),
};
}
Ok(Action::Return(previous))
}
}
#[cfg(test)]
mod tests {
use crate::abstract_tree::{Expression, ValueNode};
use super::*;
#[test]
fn run_returns_value_of_final_statement() {
let block = Block::new(vec![
Statement::Expression(Expression::Value(ValueNode::Integer(1))),
Statement::Expression(Expression::Value(ValueNode::Integer(2))),
Statement::Expression(Expression::Value(ValueNode::Integer(42))),
]);
assert_eq!(
block.run(&Context::new()),
Ok(Action::Return(Value::integer(42)))
)
}
#[test]
fn expected_type_returns_type_of_final_statement() {
let block = Block::new(vec![
Statement::Expression(Expression::Value(ValueNode::String("42"))),
Statement::Expression(Expression::Value(ValueNode::Integer(42))),
]);
assert_eq!(block.expected_type(&Context::new()), Ok(Type::Integer))
}
}