From efc79edbc068c5a4c24ff8a1a2069a1155baa3da Mon Sep 17 00:00:00 2001
From: Cat's Eye Technologies <cpressey@catseye.tc>
Date: Tue, 1 Apr 2014 14:48:07 +0100
Subject: [PATCH] It emits assembly-like code, now.

---
 README.markdown           | 30 ++++++++++++++++++++++++++++++
 src/Main.hs               | 13 +++++++++++--
 src/SixtyPical/Emitter.hs | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 76 insertions(+), 2 deletions(-)
 create mode 100644 src/SixtyPical/Emitter.hs

diff --git a/README.markdown b/README.markdown
index 2a4048a..0134610 100644
--- a/README.markdown
+++ b/README.markdown
@@ -182,3 +182,33 @@ No duplicate declarations.
     |    nop
     | }
     ? duplicate declaration
+
+    -> Tests for functionality "Emit ASM for SixtyPical program"
+    
+    -> Functionality "Emit ASM for SixtyPical program" is implemented by
+    -> shell command "bin/sixtypical emit %(test-file)"
+
+    | reserve word score
+    | assign word screen 4000
+    | routine main {
+    |    lda screen
+    |    tax
+    |    tay
+    |    cmp score
+    |    ldx score
+    |    txa
+    |    ldy score
+    |    tya
+    | }
+    = (decl)
+    = (decl)
+    = main:
+    =   lda screen
+    =   tax
+    =   tay
+    =   cmp score
+    =   (instr)
+    =   txa
+    =   (instr)
+    =   tya
+    =   rts
diff --git a/src/Main.hs b/src/Main.hs
index 74a22f4..8708629 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -10,11 +10,12 @@ import SixtyPical.Model
 import SixtyPical.Parser (parseProgram)
 import SixtyPical.Checker (checkProgram)
 import SixtyPical.Analyzer (analyzeProgram)
+import SixtyPical.Emitter (emitProgram)
 
 -- -- -- -- driver -- -- -- --
 
 usage = do
-    putStrLn "Usage: sixtypical (parse|check|analyze) filename.60pical"
+    putStrLn "Usage: sixtypical (parse|check|analyze|emit) filename.60pical"
     exitWith $ ExitFailure 1
 
 main = do
@@ -28,7 +29,15 @@ main = do
                 ("check", Right program) -> do
                     putStrLn $ show $ checkProgram program
                 ("analyze", Right program) -> do
-                    putStrLn $ show $ analyzeProgram program
+                    case checkProgram program of
+                        True ->
+                            putStrLn $ show $ analyzeProgram program
+                ("emit", Right program) -> do
+                    case checkProgram program of
+                        True ->
+                            case analyzeProgram program of
+                                _ ->
+                                    putStr $ emitProgram program
                 (_, Left problem) -> do
                     hPutStrLn stderr (show problem)
                     exitWith $ ExitFailure 1
diff --git a/src/SixtyPical/Emitter.hs b/src/SixtyPical/Emitter.hs
new file mode 100644
index 0000000..e6e0059
--- /dev/null
+++ b/src/SixtyPical/Emitter.hs
@@ -0,0 +1,35 @@
+-- encoding: UTF-8
+
+module SixtyPical.Emitter where
+
+import SixtyPical.Model
+
+emitProgram p@(Program decls routines) =
+    emitDecls p decls ++
+    emitRoutines p routines
+
+emitDecls _ [] = ""
+emitDecls p (decl:decls) =
+    emitDecl p decl ++ "\n" ++ emitDecls p decls
+
+emitDecl p _ = "(decl)"
+
+emitRoutines _ [] = ""
+emitRoutines p (rout:routs) =
+    emitRoutine p rout ++ "\n" ++ emitRoutines p routs
+
+emitRoutine p r@(Routine name instrs) =
+    name ++ ":\n" ++ emitInstrs p r instrs ++ "  rts\n"
+
+emitInstrs _ _ [] = ""
+emitInstrs p r (instr:instrs) =
+    "  " ++ emitInstr p r instr ++ "\n" ++ emitInstrs p r instrs
+
+emitInstr p r (LOAD A label) = "lda " ++ label
+emitInstr p r (CMP A label) = "cmp " ++ label
+
+emitInstr p r (COPY A X) = "tax"
+emitInstr p r (COPY A Y) = "tay"
+emitInstr p r (COPY X A) = "txa"
+emitInstr p r (COPY Y A) = "tya"
+emitInstr p r _ = "(instr)"