rust/printer.rs

   1 use types::MalVal;
   2 use types::MalVal::{Nil,Bool,Int,Str,Sym,List,Vector,Hash,Func,MalFunc,Atom};
   3
   4 fn escape_str(s: &str) -> String {
   5   s.chars().map(|c| {
   6     match c {
   7       '"' => "\\\"".to_string(),
   8       '\n' => "\\n".to_string(),
   9       '\\' => "\\\\".to_string(),
  10       _ => c.to_string(),
  11     }
  12   }).collect::<Vec<String>>().join("")
  13 }
  14
  15 impl MalVal {
  16   pub fn pr_str(&self, print_readably: bool) -> String {
  17     match self {
  18       Nil         => String::from("nil"),
  19       Bool(true)  => String::from("true"),
  20       Bool(false) => String::from("false"),
  21       Int(i)      => format!("{}", i),
  22       //Float(f)    => format!("{}", f),
  23       Str(s)      => {
  24         if s.starts_with("\u{29e}") {
  25           format!(":{}", &s[2..])
  26         } else if print_readably {
  27           format!("\"{}\"", escape_str(s))
  28         } else {
  29           s.clone()
  30         }
  31       }
  32       Sym(s)      => s.clone(),
  33       List(l,_)   => pr_seq(&**l, print_readably, "(", ")", " "),
  34       Vector(l,_) => pr_seq(&**l, print_readably, "[", "]", " "),
  35       Hash(hm,_)  => {
  36         let l: Vec<MalVal> = hm
  37           .iter()
  38           .flat_map(|(k, v)| { vec![Str(k.to_string()), v.clone()] })
  39           .collect();
  40         pr_seq(&l, print_readably, "{", "}", " ")
  41       },
  42       Func(f,_)   => format!("#<fn {:?}>", f),
  43       MalFunc{ast: a, params: p, ..} => {
  44         format!("(fn* {} {})", p.pr_str(true), a.pr_str(true))
  45       },
  46       Atom(a)     => format!("(atom {})", a.borrow().pr_str(true)),
  47     }
  48   }
  49 }
  50
  51 pub fn pr_seq(seq: &Vec<MalVal>, print_readably: bool,
  52               start: &str, end: &str, join: &str) -> String {
  53   let strs: Vec<String> = seq
  54     .iter()
  55     .map(|x| x.pr_str(print_readably))
  56     .collect();
  57   format!("{}{}{}", start, strs.join(join), end)
  58 }
  59
  60 // vim: ts=2:sw=2:expandtab