50 lines
1.4 KiB
Rust
50 lines
1.4 KiB
Rust
use serde::{Deserialize, Serialize};
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use tree_sitter::Node;
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use crate::{AbstractTree, Block, Error, Expression, Map, Result, Type, Value};
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/// Abstract representation of a while loop.
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///
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/// While executes its block repeatedly until its expression evaluates to true.
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#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq, PartialOrd, Ord)]
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pub struct While {
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expression: Expression,
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block: Block,
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}
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impl AbstractTree for While {
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fn from_syntax_node(source: &str, node: Node, context: &Map) -> crate::Result<Self> {
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Error::expect_syntax_node(source, "while", node)?;
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let expression_node = node.child(1).unwrap();
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let expression = Expression::from_syntax_node(source, expression_node, context)?;
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let block_node = node.child(2).unwrap();
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let block = Block::from_syntax_node(source, block_node, context)?;
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Ok(While { expression, block })
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}
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fn run(&self, source: &str, context: &Map) -> Result<Value> {
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while self.expression.run(source, context)?.as_boolean()? {
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self.block.run(source, context)?;
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}
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Ok(Value::Option(None))
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}
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fn expected_type(&self, context: &Map) -> Result<Type> {
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self.block.expected_type(context)
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}
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}
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#[cfg(test)]
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mod tests {
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use crate::{interpret, Value};
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#[test]
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fn evalualate_while_loop() {
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assert_eq!(interpret("while false { 'foo' }"), Ok(Value::Option(None)))
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}
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}
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