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Emits an identical rust program with comments removed and whitespace minimized.
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| use rustc_lexer::{tokenize, Token, TokenKind}; | |
| use std::io::{self, Read}; | |
| enum Cmd { | |
| Print(usize), | |
| Space, | |
| Skip(usize), | |
| } | |
| fn layout(toks: impl Iterator<Item = Token>) -> impl Iterator<Item = Cmd> { | |
| use Cmd::*; | |
| use TokenKind::*; | |
| let mut last_ident_like = false; | |
| toks.flat_map(move |Token { kind, len }| { | |
| let mut simple = match kind { | |
| Whitespace | LineComment { .. } | BlockComment { .. } => vec![], | |
| Ident | RawIdent | Literal { .. } | Lifetime { .. } if last_ident_like => { | |
| vec![Space, Print(len)] | |
| } | |
| Ident | RawIdent | Literal { .. } | Lifetime { .. } => { | |
| last_ident_like = true; | |
| vec![Print(len)] | |
| } | |
| _ => { | |
| last_ident_like = false; | |
| vec![Print(len)] | |
| } | |
| }; | |
| simple.push(Skip(len)); | |
| simple.into_iter() | |
| }) | |
| } | |
| fn emit(toks: impl Iterator<Item = Cmd>, orig: &str) -> String { | |
| use Cmd::*; | |
| let mut out = String::with_capacity(orig.len()); | |
| let mut i = 0; | |
| for tok in toks { | |
| match tok { | |
| Print(len) => out.push_str(&orig[i..i + len]), | |
| Space => out.push(' '), | |
| Skip(len) => i += len, | |
| } | |
| } | |
| out | |
| } | |
| fn main() -> io::Result<()> { | |
| let mut buffer = String::new(); | |
| io::stdin().read_to_string(&mut buffer)?; | |
| let toks = tokenize(&buffer); | |
| let cmds = layout(toks); | |
| let out = emit(cmds, &buffer); | |
| print!("{}", out); | |
| Ok(()) | |
| } |
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