73 lines
1.9 KiB
Rust
73 lines
1.9 KiB
Rust
pub struct VariableDeclarationStack
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{
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pub free_variable_declarations: crate::VariableDeclarations,
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bound_variable_declaration_stack: Vec<std::rc::Rc<crate::VariableDeclarations>>,
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}
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impl VariableDeclarationStack
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{
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pub fn new() -> Self
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{
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Self
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{
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free_variable_declarations: crate::VariableDeclarations::new(),
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bound_variable_declaration_stack: vec![],
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}
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}
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pub fn find(&self, variable_name: &str) -> Option<std::rc::Rc<crate::VariableDeclaration>>
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{
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for variable_declarations in self.bound_variable_declaration_stack.iter().rev()
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{
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if let Some(variable_declaration) = variable_declarations.iter()
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.find(|x| x.name == variable_name)
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{
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return Some(std::rc::Rc::clone(&variable_declaration));
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}
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}
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if let Some(variable_declaration) = self.free_variable_declarations.iter()
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.find(|x| x.name == variable_name)
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{
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return Some(std::rc::Rc::clone(&variable_declaration));
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}
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None
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}
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pub fn find_or_create(&mut self, variable_name: &str) -> std::rc::Rc<crate::VariableDeclaration>
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{
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if let Some(variable_declaration) = self.find(variable_name)
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{
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return variable_declaration;
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}
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let variable_declaration = crate::VariableDeclaration
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{
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name: variable_name.to_owned(),
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};
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let variable_declaration = std::rc::Rc::new(variable_declaration);
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self.free_variable_declarations.push(std::rc::Rc::clone(&variable_declaration));
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variable_declaration
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}
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pub fn is_empty(&self) -> bool
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{
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self.free_variable_declarations.is_empty()
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&& self.bound_variable_declaration_stack.is_empty()
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}
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pub fn push(&mut self, bound_variable_declarations: std::rc::Rc<crate::VariableDeclarations>)
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{
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self.bound_variable_declaration_stack.push(bound_variable_declarations);
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}
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pub fn pop(&mut self) -> Result<(), crate::Error>
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{
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self.bound_variable_declaration_stack.pop().map(|_| ())
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.ok_or_else(|| crate::Error::new_logic("variable stack not in expected state"))
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}
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}
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