From a20cff8fd8098d8571348e19de0bc604c504a58e Mon Sep 17 00:00:00 2001
From: Peter Tseng <pht24@cornell.edu>
Date: Mon, 17 Dec 2018 02:06:18 +0000
Subject: [PATCH 1/2] forth: Don't `use` Term

I prefer to make it easier to see where `term` is being used.

Also, this causes an error in Rust 2018:

    error[E0658]: imports can only refer to extern crate names passed with `--extern` on stable channel (see issue #53130)
      --> src/lib.rs:5:5
       |
    5  |   use Term::*;
       |       ^^^^

Of course there are probably other ways to fix that, but not something I
want to do right now.
---
 exercises/forth/example.rs | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/exercises/forth/example.rs b/exercises/forth/example.rs
index 3a6820a27..616a57510 100644
--- a/exercises/forth/example.rs
+++ b/exercises/forth/example.rs
@@ -2,8 +2,6 @@ use std::collections::HashMap;
 use std::collections::LinkedList;
 use std::str::FromStr;
 
-use Term::*;
-
 pub type Value = i32;
 pub type ForthResult = Result<(), Error>;
 type StackResult<T> = Result<T, Error>;
@@ -39,11 +37,11 @@ impl FromStr for Term {
 
     fn from_str(s: &str) -> Result<Term, ()> {
         match s {
-            ":" => Ok(StartDefinition),
-            ";" => Ok(EndDefinition),
+            ":" => Ok(Term::StartDefinition),
+            ";" => Ok(Term::EndDefinition),
             _ => Err(()),
-        }.or_else(|_| Value::from_str(s).map(Number))
-            .or_else(|_| Ok(Word(s.to_ascii_lowercase())))
+        }.or_else(|_| Value::from_str(s).map(Term::Number))
+            .or_else(|_| Ok(Term::Word(s.to_ascii_lowercase())))
     }
 }
 
@@ -76,10 +74,10 @@ impl Forth {
 
     fn step_term(&mut self, term: Term) -> ForthResult {
         match term {
-            Number(value) => self.push(value),
-            Word(word) => self.step_word(&word),
-            StartDefinition => self.store_definition(),
-            EndDefinition => Err(Error::InvalidWord),
+            Term::Number(value) => self.push(value),
+            Term::Word(word) => self.step_word(&word),
+            Term::StartDefinition => self.store_definition(),
+            Term::EndDefinition => Err(Error::InvalidWord),
         }
     }
 
@@ -113,13 +111,13 @@ impl Forth {
 
         loop {
             match self.code.pop_front() {
-                Some(EndDefinition) => break,
+                Some(Term::EndDefinition) => break,
                 Some(term) => def.push_back(term),
                 None => return Err(Error::InvalidWord),
             }
         }
 
-        if let Some(Word(name)) = def.pop_front() {
+        if let Some(Term::Word(name)) = def.pop_front() {
             self.store_word(name, def)
         } else {
             Err(Error::InvalidWord)

From 093e9283438634f112bf7951ccf55e1c819cb43e Mon Sep 17 00:00:00 2001
From: Peter Tseng <pht24@cornell.edu>
Date: Mon, 17 Dec 2018 02:08:55 +0000
Subject: [PATCH 2/2] forth: Use `?` not `try!`

Would cause an error in Rust 2018:

    error: expected expression, found reserved keyword `try`
      --> src/lib.rs:72:13
       |
    72 |             try!(self.step_term(term))
       |             ^^^ expected expression
---
 exercises/forth/example.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/forth/example.rs b/exercises/forth/example.rs
index 616a57510..b32e57aa9 100644
--- a/exercises/forth/example.rs
+++ b/exercises/forth/example.rs
@@ -66,7 +66,7 @@ impl Forth {
 
     fn run(&mut self) -> ForthResult {
         while let Some(term) = self.code.pop_front() {
-            try!(self.step_term(term))
+            self.step_term(term)?
         }
 
         Forth::ok()