70 lines
2.3 KiB
Rust
70 lines
2.3 KiB
Rust
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use serde::{Deserialize, Serialize};
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use tree_sitter::Node;
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use crate::{AbstractTree, Error, Expression, List, Result, Value};
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#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
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pub struct Index {
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collection: Expression,
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index: Expression,
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index_end: Option<Expression>,
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}
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impl AbstractTree for Index {
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fn from_syntax_node(source: &str, node: Node) -> Result<Self> {
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let collection_node = node.child(0).unwrap();
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let collection = Expression::from_syntax_node(source, collection_node)?;
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let index_node = node.child(3).unwrap();
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let index = Expression::from_syntax_node(source, index_node)?;
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let index_end_node = node.child(5);
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let index_end = if let Some(index_end_node) = index_end_node {
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Some(Expression::from_syntax_node(source, index_end_node)?)
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} else {
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None
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};
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Ok(Index {
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collection,
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index,
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index_end,
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})
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}
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fn run(&self, source: &str, context: &mut crate::Map) -> crate::Result<crate::Value> {
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let value = self.collection.run(source, context)?;
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match value {
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Value::List(list) => {
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let index = self.index.run(source, context)?.as_integer()? as usize;
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let item = if let Some(index_end) = &self.index_end {
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let index_end = index_end.run(source, context)?.as_integer()? as usize;
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let sublist = list.items()[index..=index_end].to_vec();
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Value::List(List::with_items(sublist))
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} else {
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list.items().get(index).cloned().unwrap_or_default()
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};
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Ok(item)
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}
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Value::Map(mut map) => {
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let value = self.index.run(source, &mut map)?;
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let index = value.as_string()?;
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let item = map.variables().get(index).cloned().unwrap_or_default();
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Ok(item)
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}
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Value::String(string) => {
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let index = self.index.run(source, context)?.as_integer()? as usize;
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let item = string.chars().nth(index).unwrap_or_default();
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Ok(Value::String(item.to_string()))
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}
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_ => return Err(Error::ExpectedCollection { actual: value }),
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}
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}
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}
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