Add [isRef] built-in

build/compile.bat

@@ -2,4 +2,4 @@
 
 FOR /F "tokens=*" %%v IN ('git log --date^=format:%%y%%m%%d --format^=%%cd -1') DO SET SOURCE_VERSION=%%v
 
-mplc.exe -D COMPILER_SOURCE_VERSION=%SOURCE_VERSION% -D DEBUG=TRUE -D DEBUG_MEMORY=TRUE -I ../sl -call_trace 0 -debug_memory -ndebug -o mplc.ll ../main.mpl
+mplc.exe -D COMPILER_SOURCE_VERSION=%SOURCE_VERSION% -D DEBUG=FALSE -D DEBUG_MEMORY=TRUE -I ../sl -call_trace 0 -debug_memory -ndebug -o mplc.ll ../main.mpl

builtinImpl.mpl

@@ -1335,6 +1335,15 @@ staticityOfBinResult: [
   ] when
 ] "mplBuiltinIsDynamic" @declareBuiltin ucall
 
+[
+  refToVar: @processor @block pop;
+  processor compilable [
+    refToVar @block push
+    refToVar getVar.temporary ~ makeValuePair
+    VarCond @processor @block createVariable Static @processor @block makeStaticity @processor @block createPlainIR @block push
+  ] when
+] "mplBuiltinIsRef" @declareBuiltin ucall
+
 [
   refToVar: @processor @block pop;
   processor compilable [

builtins.mpl

@@ -66,6 +66,7 @@ builtins: (
   {name: "isCombined"                    ; impl: @mplBuiltinIsCombined              ;}
   {name: "isConst"                       ; impl: @mplBuiltinIsConst                 ;}
   {name: "isDynamic"                     ; impl: @mplBuiltinIsDynamic               ;}
+  {name: "isRef"                         ; impl: @mplBuiltinIsRef                   ;}
   {name: "isStatic"                      ; impl: @mplBuiltinIsStatic                ;}
   {name: "log"                           ; impl: @mplBuiltinLog                     ;}
   {name: "log10"                         ; impl: @mplBuiltinLog10                   ;}