[[ StdMlc ]] Add left/right option to bitwise shift syntax

runrevali · runrevali · commit dd214971012d · 2014-12-16T18:13:05.000Z
diff --git a/libscript/src/bitwise.mlc b/libscript/src/bitwise.mlc
@@ -9,7 +9,7 @@ public foreign handler MCBitwiseEvalBitwiseOr(in Left as int, in Right as int, o
 public foreign handler MCBitwiseEvalBitwiseNot(in Operand as int, out Value as int) as undefined binds to "<builtin>"
 public foreign handler MCBitwiseEvalBitwiseXor(in Left as int, in Right as int, out Value as int) as undefined binds to "<builtin>"
 
-public foreign handler MCBitwiseEvalBitwiseShift(in Target as int, in Shift as int, out Value as int) as undefined binds to "<builtin>"
+public foreign handler MCBitwiseEvalBitwiseShift(in Target as int, in IsRight as bool, in Shift as int, out Value as int) as undefined binds to "<builtin>"
 
 --
 
@@ -125,15 +125,15 @@ Example:
 	put 7 shifted by 2 bitwise into tVar -- tVar contains 28
 
 Description:
-Shifting the bits of <Operand> by x is equivalent to multiplying by 2^x
+Shifts the bits of <Operand> left or right. If neither direction is specified, then shifts left. Shifting the bits of <Operand> left by x is equivalent to multiplying by 2^x. Shifting by a negative value is equivalent to shifting by its absolute value in the opposite direction.
 
 Tags: Bitwise operations
 */
 
 syntax BitwiseShift is postfix operator with precedence 1
-    <Operand: Expression> "shifted" "by" <Shift: Expression> "bitwise"
+    <Operand: Expression> "shifted" ("left" <IsRight=false> | "right" <IsRight=true> | <IsRight=false>) "by" <Shift: Expression> "bitwise"
 begin
-    MCBitwiseEvalBitwiseShift(Operand, Shift, output)
+    MCBitwiseEvalBitwiseShift(Operand, IsRight, Shift, output)
 end syntax
 
 --
diff --git a/libscript/src/module-bitwise.cpp b/libscript/src/module-bitwise.cpp
@@ -36,9 +36,9 @@ extern "C" MC_DLLEXPORT void MCBitwiseEvalBitwiseNot(integer_t p_operand, intege
     r_output = ~((int32_t)p_operand);
 }
 
-extern "C" MC_DLLEXPORT void MCBitwiseEvalBitwiseShift(integer_t p_operand, integer_t p_shift, integer_t& r_output)
+extern "C" MC_DLLEXPORT void MCBitwiseEvalBitwiseShift(integer_t p_operand, bool p_is_right, integer_t p_shift, integer_t& r_output)
 {
-    if (p_shift < 0)
+    if (p_shift < 0 != p_is_right)
         // truncate towards 0
         r_output = (integer_t)(p_operand >> abs(p_shift));
     else

Original file line number	Diff line number	Diff line change
`@@ -36,9 +36,9 @@ extern "C" MC_DLLEXPORT void MCBitwiseEvalBitwiseNot(integer_t p_operand, intege`
`36`	`36`	`r_output = ~((int32_t)p_operand);`
`37`	`37`	`}`
`38`	`38`
`39`		`-extern "C" MC_DLLEXPORT void MCBitwiseEvalBitwiseShift(integer_t p_operand, integer_t p_shift, integer_t& r_output)`
	`39`	`+extern "C" MC_DLLEXPORT void MCBitwiseEvalBitwiseShift(integer_t p_operand, bool p_is_right, integer_t p_shift, integer_t& r_output)`
`40`	`40`	`{`
`41`		`- if (p_shift < 0)`
	`41`	`+ if (p_shift < 0 != p_is_right)`
`42`	`42`	`// truncate towards 0`
`43`	`43`	`r_output = (integer_t)(p_operand >> abs(p_shift));`
`44`	`44`	`else`