38 lines
799 B
Rust
38 lines
799 B
Rust
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use std::rc::Rc;
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#[derive(Debug)]
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pub enum Form {
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Int(i32),
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Symbol(String),
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Pair(Rc<Form>,Rc<Form>),
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PrimComb(String, fn(Rc<Form>, Rc<Form>) -> Rc<Form>),
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Nil,
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}
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impl Form {
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pub fn int(&self) -> Option<i32> {
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match self {
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Form::Int(i) => Some(*i),
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_ => None,
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}
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}
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pub fn sym(&self) -> Option<&str> {
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match self {
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Form::Symbol(s) => Some(s),
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_ => None,
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}
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}
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pub fn car(&self) -> Option<Rc<Form>> {
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match self {
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Form::Pair(car, cdr) => Some(Rc::clone(car)),
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_ => None,
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}
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}
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pub fn cdr(&self) -> Option<Rc<Form>> {
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match self {
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Form::Pair(car, cdr) => Some(Rc::clone(cdr)),
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_ => None,
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}
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}
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}
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