From feef2ecf3f556c88f50acf0341d34499ed9d7c4c Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <jolesen@mozilla.com>
Date: Mon, 19 Sep 2016 10:08:21 -0700
Subject: [PATCH] Extract Result and Error into their own module.

Also include the err! macro and make it usable outside the module.
---
 src/libreader/error.rs    | 44 +++++++++++++++++++++++++++++++++++++++
 src/libreader/lexer.rs    |  8 ++-----
 src/libreader/lib.rs      |  4 +++-
 src/libreader/parser.rs   | 40 +++--------------------------------
 src/libreader/testfile.rs |  2 +-
 5 files changed, 53 insertions(+), 45 deletions(-)
 create mode 100644 src/libreader/error.rs

diff --git a/src/libreader/error.rs b/src/libreader/error.rs
new file mode 100644
index 0000000000..edc6e40649
--- /dev/null
+++ b/src/libreader/error.rs
@@ -0,0 +1,44 @@
+//! Define the `Location`, `Error`, and `Result` types.
+
+#![macro_use]
+
+use std::fmt;
+use std::result;
+
+/// The location of a `Token` or `Error`.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct Location {
+    pub line_number: usize,
+}
+
+/// A parse error is returned when the parse failed.
+#[derive(Debug)]
+pub struct Error {
+    pub location: Location,
+    pub message: String,
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}: {}", self.location.line_number, self.message)
+    }
+}
+
+pub type Result<T> = result::Result<T, Error>;
+
+// Create an `Err` variant of `Result<X>` from a location and `format!` args.
+macro_rules! err {
+    ( $loc:expr, $msg:expr ) => {
+        Err($crate::Error {
+            location: $loc.clone(),
+            message: String::from($msg),
+        })
+    };
+
+    ( $loc:expr, $fmt:expr, $( $arg:expr ),+ ) => {
+        Err($crate::Error {
+            location: $loc.clone(),
+            message: format!( $fmt, $( $arg ),+ ),
+        })
+    };
+}
diff --git a/src/libreader/lexer.rs b/src/libreader/lexer.rs
index 6b5e881a1f..7631e306ad 100644
--- a/src/libreader/lexer.rs
+++ b/src/libreader/lexer.rs
@@ -8,12 +8,7 @@
 use std::str::CharIndices;
 use cretonne::ir::types;
 use cretonne::ir::{Value, Ebb};
-
-/// The location of a `Token` or `Error`.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct Location {
-    pub line_number: usize,
-}
+use error::Location;
 
 /// A Token returned from the `Lexer`.
 ///
@@ -379,6 +374,7 @@ mod tests {
     use super::*;
     use cretonne::ir::types;
     use cretonne::ir::{Value, Ebb};
+    use error::Location;
 
     fn token<'a>(token: Token<'a>, line: usize) -> Option<Result<LocatedToken<'a>, LocatedError>> {
         Some(super::token(token, Location { line_number: line }))
diff --git a/src/libreader/lib.rs b/src/libreader/lib.rs
index 79f9b23521..f0f04fa381 100644
--- a/src/libreader/lib.rs
+++ b/src/libreader/lib.rs
@@ -5,11 +5,13 @@
 
 extern crate cretonne;
 
-pub use parser::{Result, parse_functions, parse_test};
+pub use error::{Location, Result, Error};
+pub use parser::{parse_functions, parse_test};
 pub use testcommand::{TestCommand, TestOption};
 pub use testfile::{TestFile, Details};
 pub use sourcemap::SourceMap;
 
+mod error;
 mod lexer;
 mod parser;
 mod testcommand;
diff --git a/src/libreader/parser.rs b/src/libreader/parser.rs
index 6fea02b22b..68a5e72a4f 100644
--- a/src/libreader/parser.rs
+++ b/src/libreader/parser.rs
@@ -6,12 +6,9 @@
 // ====--------------------------------------------------------------------------------------====//
 
 use std::collections::HashMap;
-use std::result;
-use std::fmt::{self, Display, Formatter};
 use std::str::FromStr;
 use std::u32;
 use std::mem;
-use lexer::{self, Lexer, Token};
 use cretonne::ir::{Function, Ebb, Inst, Opcode, Value, Type, FunctionName, StackSlot,
                    StackSlotData, JumpTable, JumpTableData};
 use cretonne::ir::types::{VOID, Signature, ArgumentType, ArgumentExtension};
@@ -20,11 +17,11 @@ use cretonne::ir::entities::{AnyEntity, NO_EBB, NO_INST, NO_VALUE};
 use cretonne::ir::instructions::{InstructionFormat, InstructionData, VariableArgs, JumpData,
                                  BranchData, ReturnData};
 use testfile::{TestFile, Details, Comment};
+use error::{Location, Error, Result};
+use lexer::{self, Lexer, Token};
 use testcommand::TestCommand;
 use sourcemap;
 
-pub use lexer::Location;
-
 /// Parse the entire `text` into a list of functions.
 ///
 /// Any test commands or ISA declarations are ignored.
@@ -43,38 +40,6 @@ pub fn parse_test<'a>(text: &'a str) -> Result<TestFile<'a>> {
     })
 }
 
-/// A parse error is returned when the parse failed.
-#[derive(Debug)]
-pub struct Error {
-    pub location: Location,
-    pub message: String,
-}
-
-impl Display for Error {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "{}: {}", self.location.line_number, self.message)
-    }
-}
-
-pub type Result<T> = result::Result<T, Error>;
-
-// Create an `Err` variant of `Result<X>` from a location and `format!` args.
-macro_rules! err {
-    ( $loc:expr, $msg:expr ) => {
-        Err(Error {
-            location: $loc.clone(),
-            message: String::from($msg),
-        })
-    };
-
-    ( $loc:expr, $fmt:expr, $( $arg:expr ),+ ) => {
-        Err(Error {
-            location: $loc.clone(),
-            message: format!( $fmt, $( $arg ),+ ),
-        })
-    };
-}
-
 pub struct Parser<'a> {
     lex: Lexer<'a>,
 
@@ -1225,6 +1190,7 @@ mod tests {
     use cretonne::ir::types::{self, ArgumentType, ArgumentExtension};
     use cretonne::ir::entities::AnyEntity;
     use testfile::{Details, Comment};
+    use error::Error;
 
     #[test]
     fn argument_type() {
diff --git a/src/libreader/testfile.rs b/src/libreader/testfile.rs
index 8a9f8d3451..d63b1f9f9d 100644
--- a/src/libreader/testfile.rs
+++ b/src/libreader/testfile.rs
@@ -8,7 +8,7 @@ use cretonne::ir::Function;
 use cretonne::ir::entities::AnyEntity;
 use testcommand::TestCommand;
 use sourcemap::SourceMap;
-use parser::Location;
+use error::Location;
 
 /// A parsed test case.
 ///