39 lines
1.1 KiB
Rust
39 lines
1.1 KiB
Rust
use std::{collections::HashMap, mem::Discriminant};
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use super::{Identifier, value::Value, expr::Operation, types::Type};
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#[derive(Debug, Default)]
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pub struct ValueBindings<'a>(Option<&'a ValueBindings<'a>>, HashMap<u128, Value>);
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impl<'a> ValueBindings<'a> {
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pub fn bind(mut self, ident: &Identifier, value: Value) -> Self {
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self.1.insert(ident.1 as u128, value);
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self
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}
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pub fn lookup(&self, ident: &Identifier) -> Option<&Value> {
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self.1.get(&(ident.1 as u128))
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.or_else(|| self.0.and_then(|binding| binding.lookup(ident)))
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}
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pub fn nested_scope(&'a self) -> ValueBindings<'a> {
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ValueBindings(Some(self), HashMap::new())
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}
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pub fn get_main(&self) -> Option<&Value> {
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self.1.get(&3).or_else(|| self.0.and_then(ValueBindings::get_main))
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}
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}
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pub enum EvaluateError {
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UndefinedValue(Identifier),
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EvaluatingZeroLengthExpr,
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ArgumentCountMismatch(Operation, usize, usize),
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FunctionArgumentCountMismatch(usize, usize),
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TypeMismatch(Discriminant<Value>, Discriminant<Value>),
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NoMain,
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MainHasArgs,
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}
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pub type Result = std::result::Result<Value, EvaluateError>;
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