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use std::fmt::Write; use std::{collections::HashMap, path::PathBuf, rc::Rc}; pub trait Codegen { fn gen_code(&self, res: &mut CodegenResult, out: &mut String); } impl<'a, T> Codegen for &'a T where T: Codegen, { fn gen_code(&self, res: &mut CodegenResult, out: &mut String) { (*self).gen_code(res, out) } } #[derive(Default)] pub struct CodegenResult { codes: HashMap<String, usize>, id: usize, snippets: Vec<String>, } impl CodegenResult { pub fn add_code(&mut self, code: String, ty: &str) -> String { let var_name = if !self.codes.contains_key(&code) { let value = self.id; self.id += 1; self.codes.insert(code.clone(), value); let var_name = format!("code_{:x}", value); self.snippets .push(format!("let {}{} = {};", var_name, ty, code)); var_name } else { let value = self.codes.get(&code).unwrap(); format!("code_{:x}", value) }; format!("{}.clone()", var_name) } pub fn add_rc_value<T: Codegen + ?Sized>(&mut self, s: &T) -> String { let mut out = String::new(); s.gen_code(self, &mut out); self.add_code(format!("::std::rc::Rc::new({})", out), "") } pub fn add_into_rc_value(&mut self, s: &impl Codegen, ty: &'static str) -> String { let mut out = String::new(); s.gen_code(self, &mut out); self.add_code( format!("{}.into()", out), &format!(": ::std::rc::Rc<{}>", ty), ) } pub fn add_value(&mut self, s: &impl Codegen) -> String { let mut out = String::new(); s.gen_code(self, &mut out); out } pub fn codegen(&mut self, s: &impl Codegen) -> String { let mut out = String::new(); s.gen_code(self, &mut out); let mut real_out = String::new(); real_out.push_str("{"); for snip in self.snippets.iter() { real_out.push_str(&snip); real_out.push_str("\n"); } real_out.push_str(&out); real_out.push_str("}"); real_out } } impl<T: Codegen> Codegen for &Option<T> { fn gen_code(&self, res: &mut CodegenResult, out: &mut String) { write!(out, "std::option::Option::").unwrap(); if self.is_some() { let v = self.as_ref().unwrap(); write!(out, "Some({})", res.add_value(v)).unwrap(); } else { write!(out, "None").unwrap(); } } } impl Codegen for Rc<str> { fn gen_code(&self, res: &mut CodegenResult, out: &mut String) { let s: &str = &*self; write!(out, "{}", res.add_into_rc_value(&s, "str")).unwrap() } } impl<T: Codegen> Codegen for Rc<T> { fn gen_code(&self, res: &mut CodegenResult, out: &mut String) { let v: &T = &**self; out.push_str(&res.add_rc_value(v)); } } impl<T: Codegen> Codegen for Vec<T> { fn gen_code(&self, res: &mut CodegenResult, out: &mut String) { out.push_str("vec!["); for i in self.iter() { out.push_str(&res.add_value(i)); out.push(','); } out.push_str("]"); } } impl Codegen for &str { fn gen_code(&self, _res: &mut CodegenResult, out: &mut String) { out.push('"'); out.push_str(&self.escape_debug().collect::<String>()); out.push('"'); } } impl Codegen for String { fn gen_code(&self, res: &mut CodegenResult, out: &mut String) { (&self as &str).gen_code(res, out) } } impl Codegen for PathBuf { fn gen_code(&self, _res: &mut CodegenResult, out: &mut String) { out.push_str("std::path::PathBuf::from(\""); out.push_str(&self.to_str().unwrap().escape_debug().collect::<String>()); out.push_str("\")"); } } impl Codegen for &bool { fn gen_code(&self, _res: &mut CodegenResult, out: &mut String) { write!(out, "{}", self).unwrap() } } macro_rules! num_impl { ($t:ty) => { impl Codegen for &$t { fn gen_code(&self, _res: &mut CodegenResult, out: &mut String) { out.push('"'); write!(out, "{}{}", self, stringify!($t)).unwrap(); out.push('"'); } } }; } num_impl!(u8); num_impl!(u16); num_impl!(u32); num_impl!(u64); num_impl!(i8); num_impl!(i16); num_impl!(i32); num_impl!(i64); num_impl!(f32); num_impl!(f64); num_impl!(isize); num_impl!(usize);