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dust/dust-lang/src/abstract_tree/block.rs

121 lines
2.9 KiB
Rust

use std::fmt::{self, Display, Formatter};
use serde::{Deserialize, Serialize};
use crate::{
context::Context,
error::{RuntimeError, ValidationError},
};
use super::{AbstractNode, Evaluation, Statement, Type};
#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Serialize, Deserialize)]
pub struct Block {
statements: Vec<Statement>,
}
impl Block {
pub fn new(statements: Vec<Statement>) -> Self {
Self { statements }
}
pub fn first_statement(&self) -> &Statement {
self.statements.first().unwrap()
}
pub fn last_statement(&self) -> &Statement {
self.statements.last().unwrap()
}
}
impl AbstractNode for Block {
fn define_and_validate(
&self,
_context: &Context,
_manage_memory: bool,
) -> Result<(), ValidationError> {
for statement in &self.statements {
statement.define_and_validate(_context, _manage_memory)?;
}
Ok(())
}
fn evaluate(
self,
_context: &Context,
_manage_memory: bool,
) -> Result<Option<Evaluation>, RuntimeError> {
let mut previous = None;
for statement in self.statements {
previous = statement.evaluate(_context, _manage_memory)?;
}
Ok(previous)
}
fn expected_type(&self, _context: &Context) -> Result<Option<Type>, ValidationError> {
self.last_statement().expected_type(_context)
}
}
impl Display for Block {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(f, "{{ ")?;
for statement in &self.statements {
write!(f, "{statement} ")?;
}
write!(f, "}}")
}
}
#[cfg(test)]
mod tests {
use crate::{
abstract_tree::{Expression, ValueNode, WithPos},
Value,
};
use super::*;
#[test]
fn run_returns_value_of_final_statement() {
let block = Block::new(vec![
Statement::Expression(Expression::Value(
ValueNode::Integer(1).with_position((0, 0)),
)),
Statement::Expression(Expression::Value(
ValueNode::Integer(2).with_position((0, 0)),
)),
Statement::Expression(Expression::Value(
ValueNode::Integer(42).with_position((0, 0)),
)),
]);
assert_eq!(
block.evaluate(&Context::new(None), true).unwrap(),
Some(Evaluation::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".to_string()).with_position((0, 0)),
)),
Statement::Expression(Expression::Value(
ValueNode::Integer(42).with_position((0, 0)),
)),
]);
assert_eq!(
block.expected_type(&Context::new(None)),
Ok(Some(Type::Integer))
)
}
}