src/libsyntax/show_span.rs

   1 // Copyright 2014 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 //! Span debugger
  12 //!
  13 //! This module shows spans for all expressions in the crate
  14 //! to help with compiler debugging.
  15
  16 use std::str::FromStr;
  17
  18 use ast;
  19 use errors;
  20 use visit;
  21 use visit::Visitor;
  22
  23 enum Mode {
  24     Expression,
  25     Pattern,
  26     Type,
  27 }
  28
  29 impl FromStr for Mode {
  30     type Err = ();
  31     fn from_str(s: &str) -> Result<Mode, ()> {
  32         let mode = match s {
  33             "expr" => Mode::Expression,
  34             "pat" => Mode::Pattern,
  35             "ty" => Mode::Type,
  36             _ => return Err(())
  37         };
  38         Ok(mode)
  39     }
  40 }
  41
  42 struct ShowSpanVisitor<'a> {
  43     span_diagnostic: &'a errors::Handler,
  44     mode: Mode,
  45 }
  46
  47 impl<'a, 'v> Visitor<'v> for ShowSpanVisitor<'a> {
  48     fn visit_expr(&mut self, e: &ast::Expr) {
  49         if let Mode::Expression = self.mode {
  50             self.span_diagnostic.span_warn(e.span, "expression");
  51         }
  52         visit::walk_expr(self, e);
  53     }
  54
  55     fn visit_pat(&mut self, p: &ast::Pat) {
  56         if let Mode::Pattern = self.mode {
  57             self.span_diagnostic.span_warn(p.span, "pattern");
  58         }
  59         visit::walk_pat(self, p);
  60     }
  61
  62     fn visit_ty(&mut self, t: &ast::Ty) {
  63         if let Mode::Type = self.mode {
  64             self.span_diagnostic.span_warn(t.span, "type");
  65         }
  66         visit::walk_ty(self, t);
  67     }
  68
  69     fn visit_mac(&mut self, mac: &ast::Mac) {
  70         visit::walk_mac(self, mac);
  71     }
  72 }
  73
  74 pub fn run(span_diagnostic: &errors::Handler,
  75            mode: &str,
  76            krate: &ast::Crate) {
  77     let mode = match mode.parse().ok() {
  78         Some(mode) => mode,
  79         None => return
  80     };
  81     let mut v = ShowSpanVisitor {
  82         span_diagnostic: span_diagnostic,
  83         mode: mode,
  84     };
  85     visit::walk_crate(&mut v, krate);
  86 }