From 2788df88e6261ac641adf9f39bbfe517a7d77d9c Mon Sep 17 00:00:00 2001
From: Camil Staps
Date: Wed, 19 Jul 2017 12:25:45 +0000
Subject: Add else if

---
 Sil/Compile.icl      | 38 +++++++++++++++++---------------------
 Sil/Parse.icl        | 19 +++++++++++++------
 Sil/Syntax.dcl       |  2 +-
 Sil/Syntax.icl       |  2 +-
 Sil/Util/Printer.icl | 13 +++++++------
 5 files changed, 39 insertions(+), 35 deletions(-)

(limited to 'Sil')

diff --git a/Sil/Compile.icl b/Sil/Compile.icl
index 42fa162..abed973 100644
--- a/Sil/Compile.icl
+++ b/Sil/Compile.icl
@@ -190,28 +190,24 @@ where
 	gen (Return (Just app)) = comment "Return" *> gen app *> cleanup *> tell ['ABC'.Rtn]
 	gen (Return Nothing)    = comment "Return" *> cleanup *> tell ['ABC'.Rtn]
 	gen (MachineStm s)      = tell ['ABC'.Raw s]
-	gen (If c t Nothing) =
+	gen (If blocks else) =
 		fresh "ifend" >>= \end ->
-		comment "condition" *>
-		gen c *>
-		toBStack 'ABC'.BT_Bool 1 *>
-		tell [ 'ABC'.JmpFalse end ] *>
-		comment "if-true" *>
-		gen t *>
-		tell [ 'ABC'.Label end ]
-	gen (If c t (Just e)) =
-		fresh "else" >>= \else -> fresh "ifend" >>= \end ->
-		comment "condition" *>
-		gen c *>
-		toBStack 'ABC'.BT_Bool 1 *>
-		tell [ 'ABC'.JmpFalse else ] *>
-		comment "if-true" *>
-		gen t *>
-		tell [ 'ABC'.Jmp end
-		     , 'ABC'.Label else ] *>
-		comment "if-false" *>
-		gen e *>
-		tell [ 'ABC'.Label end ]
+		mapM_ (genifblock end) blocks *>
+		genelse end else
+	where
+		genifblock :: 'ABC'.Label (Application, CodeBlock) -> Gen ()
+		genifblock end (cond, cb) =
+			fresh "ifelse" >>= \else ->
+			gen cond *>
+			toBStack 'ABC'.BT_Bool 1 *>
+			tell [ 'ABC'.JmpFalse else ] *>
+			gen cb *>
+			tell [ 'ABC'.Jmp end
+			     , 'ABC'.Label else ]
+
+		genelse :: 'ABC'.Label (Maybe CodeBlock) -> Gen ()
+		genelse end Nothing   = tell ['ABC'.Label end]
+		genelse end (Just cb) = gen cb *> tell ['ABC'.Label end]
 
 instance gen Application
 where
diff --git a/Sil/Parse.icl b/Sil/Parse.icl
index 3a11622..2e21d08 100644
--- a/Sil/Parse.icl
+++ b/Sil/Parse.icl
@@ -138,17 +138,18 @@ initialisation =
 	pure [{init_type=t, init_name=n} \\ n <- ns]
 
 statement :: Parser Token Statement
-statement = ((declaration
-	<|> liftM Application application
+statement = declaration
+	<|> liftM Application (application <* item TSemicolon)
 	<|> return
 	<|> if`
-	/*<|> while*/) <* item TSemicolon) <|> machinecode
+	//<|> while
+	<|> machinecode
 where
 	declaration :: Parser Token Statement
-	declaration = liftM2 Declaration name (item TAssign *> application)
+	declaration = liftM2 Declaration name (item TAssign *> application <* item TSemicolon)
 
 	return :: Parser Token Statement
-	return = liftM Return (item TReturn *> optional application)
+	return = liftM Return (item TReturn *> optional application <* item TSemicolon)
 
 	machinecode :: Parser Token Statement
 	machinecode = (\(TMachineCode s) -> MachineStm s) <$> satisfy isMachineCode
@@ -158,8 +159,14 @@ where
 	if` = item TIf *>
 		parenthised application >>= \cond ->
 		braced codeblock >>= \iftrue ->
+		many elseif >>= \elseifs ->
 		optional (item TElse *> braced codeblock) >>= \iffalse ->
-		pure $ If cond iftrue iffalse
+		pure $ If [(cond,iftrue):elseifs] iffalse
+	where
+		elseif = list [TElse, TIf] *>
+			parenthised application >>= \cond ->
+			braced codeblock >>= \block ->
+			pure (cond, block)
 
 application :: Parser Token Application
 application
diff --git a/Sil/Syntax.dcl b/Sil/Syntax.dcl
index 5c91dc6..b3ecdb7 100644
--- a/Sil/Syntax.dcl
+++ b/Sil/Syntax.dcl
@@ -34,7 +34,7 @@ from Data.Maybe import :: Maybe
 	= Declaration Name Application
 	| Application Application
 	| Return (Maybe Application)
-	| If Application CodeBlock (Maybe CodeBlock)
+	| If [(Application, CodeBlock)] (Maybe CodeBlock)
 	| While Application CodeBlock
 	| MachineStm String
 
diff --git a/Sil/Syntax.icl b/Sil/Syntax.icl
index 934a300..ec7aafa 100644
--- a/Sil/Syntax.icl
+++ b/Sil/Syntax.icl
@@ -14,7 +14,7 @@ where
 	toString (Application app) = toString app <+ ";"
 	toString (Return Nothing)  = "return;"
 	toString (Return (Just a)) = "return " <+ a <+ ";"
-	toString (If c t e)        = "if (" <+ c <+ ") ..."
+	toString (If bs e)         = "if ..."
 	toString (MachineStm s)    = "|~" <+ s
 	toString _                 = "<<unimplemented Statement>>"
 
diff --git a/Sil/Util/Printer.icl b/Sil/Util/Printer.icl
index 2252ee4..af3d072 100644
--- a/Sil/Util/Printer.icl
+++ b/Sil/Util/Printer.icl
@@ -91,12 +91,13 @@ where
 
 instance PrettyPrinter Statement
 where
-	print st (If c t Nothing) = st <+ "if (" <+ c <+ ") {\r\n" <+
-		print (incIndent st) t <+ "\r\n" <+ st <+ "}"
-	print st (If c t (Just e)) = st <+ "if (" <+ c <+ ") {\r\n" <+
-		print st` t <+ "\r\n" <+ st <+ "} else {\r\n" <+
-		print st` e <+ "\r\n" <+ st <+ "}"
-	where st` = incIndent st
+	print st (If bs else) = st <+ printersperse " else " (map oneblock bs) <+ else`
+	where
+		st` = incIndent st
+		oneblock (c,b) = "if (" <+ c <+ ") {\r\n" <+ print st` b <+ "\r\n" <+ st <+ "}"
+		else` = case else of
+			Nothing -> ""
+			Just e  -> " else {\r\n" <+ print st` e <+ "\r\n" <+ st <+ "}"
 	print st stm = st <+ stm
 
 printersperse :: a [b] -> String | toString a & toString b
-- 
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