From ee9a082ac97bd1fa408fb585e80a53ade3a8582f Mon Sep 17 00:00:00 2001
From: Isabelle L <me@izzabelle.dev>
Date: Wed, 24 Jun 2020 18:59:13 -0500
Subject: [PATCH] cargo clippy to clean some stuff up

---
 ceres-asm/src/lib.rs | 76 ++++++++++++++++++++------------------------
 test.asm             |  1 +
 2 files changed, 35 insertions(+), 42 deletions(-)

diff --git a/ceres-asm/src/lib.rs b/ceres-asm/src/lib.rs
index 3a43db3..874d52f 100644
--- a/ceres-asm/src/lib.rs
+++ b/ceres-asm/src/lib.rs
@@ -13,11 +13,9 @@ pub type Result<T> = std::result::Result<T, CeresAsmError>;
 /// ceres-asm error type
 #[derive(Debug, thiserror::Error)]
 pub enum CeresAsmError {
-    #[error("wrong token found:\nexpected: {expected:?}\n found: {found:?}")]
-    BadToken { expected: Token, found: Token },
-    #[error("bad token: {token:?}")]
-    LazyBadToken { token: Token },
-    #[error("was looking for token, found nothing ???")]
+    #[error("wrong token found:\nexpected: {expected}\n found: {found:?}")]
+    BadToken { expected: String, found: Token },
+    #[error("was looking for token, found nothing")]
     NoToken,
     #[error(transparent)]
     StdIo(#[from] std::io::Error),
@@ -49,9 +47,19 @@ impl<'a> Assembler<'a> {
                 Token::Add => machine_code.push(self.register_instruction(0b00010u32)?),
                 Token::Sub => machine_code.push(self.register_instruction(0b00011u32)?),
                 // cases that should straight up not happen
-                _ => return Err(CeresAsmError::LazyBadToken { token }),
+                _ => {
+                    return Err(CeresAsmError::BadToken {
+                        expected: "an instruction".to_owned(),
+                        found: token,
+                    })
+                }
             }
         }
+
+        // pad with empty space
+        (0..(((std::u16::MAX / 2) as usize) - machine_code.len()))
+            .for_each(|_| machine_code.push(0x0000_0000u32));
+
         Ok(MachineCode(machine_code))
     }
 
@@ -76,7 +84,7 @@ impl<'a> Assembler<'a> {
 
     fn immediate_instruction(&mut self, opcode: u32) -> Result<u32> {
         let token = self.next()?;
-        let signifier = Signifier::from_token(&token)?.as_bits() as u32;
+        let signifier = token.signifier_bits()? as u32;
         let token = self.next()?;
         let register = token.register_index()? as u32;
         let token = self.next()?;
@@ -108,32 +116,6 @@ impl MachineCode {
     }
 }
 
-enum Signifier {
-    VideoMemory,
-    CartMemory,
-    Immediate,
-}
-
-impl Signifier {
-    fn from_token(token: &Token) -> Result<Self> {
-        match token {
-            Token::VideoMemory => Ok(Self::VideoMemory),
-            Token::CartMemory => Ok(Self::CartMemory),
-            Token::Immediate => Ok(Self::Immediate),
-            _ => Err(CeresAsmError::LazyBadToken { token: token.clone() }),
-        }
-    }
-
-    // returns the signifier as bits stored in a u8
-    fn as_bits(self) -> u8 {
-        match self {
-            Self::VideoMemory => 0b010,
-            Self::CartMemory => 0b001,
-            Self::Immediate => 0b100,
-        }
-    }
-}
-
 /// token
 #[derive(Logos, Debug, PartialEq, Clone, Copy)]
 pub enum Token {
@@ -199,10 +181,10 @@ pub enum Token {
 
 impl Token {
     // returns the index of a register
-    fn register_index(&self) -> Result<u8> {
+    fn register_index(self) -> Result<u8> {
         match self {
-            Self::RegisterIndex(index) => Ok(index.clone() as u8),
-            Self::TemporaryRegister(index) => Ok(index.clone() as u8 + 9),
+            Self::RegisterIndex(index) => Ok(index as u8),
+            Self::TemporaryRegister(index) => Ok(index as u8 + 9),
             Self::ZeroRegister => Ok(0),
             Self::ProgramCounter => Ok(1),
             Self::StackPointer => Ok(2),
@@ -212,17 +194,27 @@ impl Token {
             Self::ArgumentTwo => Ok(6),
             Self::ReturnZero => Ok(7),
             Self::ReturnOne => Ok(8),
-            _ => return Err(CeresAsmError::LazyBadToken { token: self.clone() }),
+            _ => Err(CeresAsmError::BadToken { expected: "a register".to_owned(), found: self }),
         }
     }
 
     // returns literals as a u16
-    fn literal(&self) -> Result<u16> {
+    fn literal(self) -> Result<u16> {
+        match self {
+            Self::HexLiteral(val) => Ok(val),
+            Self::BinaryLiteral(val) => Ok(val),
+            Self::DecimalLiteral(val) => Ok(val),
+            _ => Err(CeresAsmError::BadToken { expected: "a literal".to_owned(), found: self }),
+        }
+    }
+
+    // if the token is a signifier return it's bits
+    fn signifier_bits(self) -> Result<u8> {
         match self {
-            Self::HexLiteral(val) => Ok(*val),
-            Self::BinaryLiteral(val) => Ok(*val),
-            Self::DecimalLiteral(val) => Ok(*val),
-            _ => Err(CeresAsmError::LazyBadToken { token: self.clone() }),
+            Self::CartMemory => Ok(0b001u8),
+            Self::VideoMemory => Ok(0b010u8),
+            Self::Immediate => Ok(0b100u8),
+            _ => Err(CeresAsmError::BadToken { expected: "a signifier".to_owned(), found: self }),
         }
     }
 }
diff --git a/test.asm b/test.asm
index 6c1316a..95f5b86 100644
--- a/test.asm
+++ b/test.asm
@@ -2,3 +2,4 @@
 ld:immd $t1 0x3333
 ld:immd $t2 0x1111
 add $t1 $t2 $t3
+sub $t3 $t2 $t4
\ No newline at end of file