src/libsyntax/parse/prec.rs

   1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use ast;
  12 use ast::*;
  13 use parse::token::*;
  14 use parse::token::Token;
  15
  16 use core::prelude::*;
  17
  18 /// Unary operators have higher precedence than binary
  19 pub static unop_prec: uint = 100u;
  20
  21 /**
  22  * Precedence of the `as` operator, which is a binary operator
  23  * but is not represented in the precedence table.
  24  */
  25 pub static as_prec: uint = 11u;
  26
  27 /**
  28  * Maps a token to a record specifying the corresponding binary
  29  * operator and its precedence
  30  */
  31 pub fn token_to_binop(tok: Token) -> Option<ast::binop> {
  32   match tok {
  33       BINOP(STAR)    => Some(mul),
  34       BINOP(SLASH)   => Some(div),
  35       BINOP(PERCENT) => Some(rem),
  36       // 'as' sits between here with 11
  37       BINOP(PLUS)    => Some(add),
  38       BINOP(MINUS)   => Some(subtract),
  39       BINOP(SHL)     => Some(shl),
  40       BINOP(SHR)     => Some(shr),
  41       BINOP(AND)     => Some(bitand),
  42       BINOP(CARET)   => Some(bitxor),
  43       BINOP(OR)      => Some(bitor),
  44       LT             => Some(lt),
  45       LE             => Some(le),
  46       GE             => Some(ge),
  47       GT             => Some(gt),
  48       EQEQ           => Some(eq),
  49       NE             => Some(ne),
  50       ANDAND         => Some(and),
  51       OROR           => Some(or),
  52       _              => None
  53   }
  54 }