dust/src/abstract_tree/index.rs
2023-11-12 13:20:41 -05:00

106 lines
3.1 KiB
Rust

use serde::{Deserialize, Serialize};
use tree_sitter::Node;
use crate::{AbstractTree, Error, Expression, List, Map, Result, Value};
#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
pub struct Index {
collection: Expression,
index: Expression,
index_end: Option<Expression>,
}
impl AbstractTree for Index {
fn from_syntax_node(source: &str, node: Node) -> Result<Self> {
let collection_node = node.child(0).unwrap();
let collection = Expression::from_syntax_node(source, collection_node)?;
let index_node = node.child(2).unwrap();
let index = Expression::from_syntax_node(source, index_node)?;
let index_end_node = node.child(4);
let index_end = if let Some(index_end_node) = index_end_node {
Some(Expression::from_syntax_node(source, index_end_node)?)
} else {
None
};
Ok(Index {
collection,
index,
index_end,
})
}
fn run(&self, source: &str, context: &mut Map) -> Result<Value> {
let value = self.collection.run(source, context)?;
println!("{self:?}");
match value {
Value::List(list) => {
let index = self.index.run(source, context)?.as_integer()? as usize;
let item = if let Some(index_end) = &self.index_end {
let index_end = index_end.run(source, context)?.as_integer()? as usize;
let sublist = list.items()[index..=index_end].to_vec();
Value::List(List::with_items(sublist))
} else {
list.items().get(index).cloned().unwrap_or_default()
};
Ok(item)
}
Value::Map(mut map) => {
let value = if let Expression::Identifier(identifier) = &self.index {
let key = identifier.inner();
map.variables()?.get(key).cloned().unwrap_or(Value::Empty)
} else {
let value = self.index.run(source, &mut map)?;
let key = value.as_string()?;
map.variables()?.get(key).cloned().unwrap_or(Value::Empty)
};
Ok(value)
}
Value::String(string) => {
let index = self.index.run(source, context)?.as_integer()? as usize;
let item = string.chars().nth(index).unwrap_or_default();
Ok(Value::String(item.to_string()))
}
_ => Err(Error::ExpectedCollection { actual: value }),
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::evaluate;
#[test]
fn evaluate_list_index() {
let test = evaluate("x = [1 [2] 3] x:1:0").unwrap();
assert_eq!(Value::Integer(2), test);
}
#[test]
fn evaluate_map_index() {
let test = evaluate("x = {y = {z = 2}} x:y:z").unwrap();
assert_eq!(Value::Integer(2), test);
}
#[test]
fn evaluate_complex_index() {
let test = evaluate("x = [1 2 3]; y = || => {0}; x:((y));").unwrap();
assert_eq!(Value::Integer(1), test);
}
}