fbc: sf.net #843: Implicit casting of argument to string works for Instr() and Mid() but not for Left() and Right()

Author: jayrm

changelog.txt

@@ -38,6 +38,7 @@ Version 1.09.0
 - darwin: a variety of improvements to allow compiling and linking (TeeEmCee)
 - gfxlib2: fix d2d scaling issues for high dpi (adeyblue)
 - fbc: improve error message on statement between SELECT and first CASE inside a subroutine and don't allow CONST/ENUM between any SELECT & first CASE.
+- sf.net #843: Implicit casting of argument to string works for Instr() and Mid() but not for Left() and Right() 
 
 
 Version 1.08.0

src/compiler/symb-data.bas

@@ -134,7 +134,7 @@ sub symbDataInit( )
 		'' populate symb_dtypeMatchTB() with ranking numbers
 		for i = 0 to NUMTYPES - 1
 			dtype2 = rank(i)
-			symb_dtypeMatchTB( dtype1, dtype2 ) = i
+			symb_dtypeMatchTB( dtype1, dtype2 ) = i * FB_OVLPROC_CONVSCALE
 		next
 
 	next
@@ -533,6 +533,8 @@ end function
 '' FB_OVLPROC_LOWEST_MATCH           => compatible, lowest scoring parameter
 '' FB_OVLPROC_NO_MATCH               => incompatible
 
+'' FB_OVLPROC_CONVSCALE              => granularity of the matching score
+
 ''
 function typeCalcMatch _
 	( _
@@ -558,7 +560,7 @@ function typeCalcMatch _
 	end if
 
 	if( (typeGetDtAndPtrOnly( ldtype ) = typeGetDtAndPtrOnly( rdtype )) and (lsubtype = rsubtype) ) then
-		return FB_OVLPROC_TYPEMATCH + const_matches
+		return FB_OVLPROC_TYPEMATCH + const_matches * FB_OVLPROC_CONVSCALE
 	end if
 
 	'' We know that they're different (in terms of dtype or subtype or both),

src/compiler/symb-proc.bas

@@ -1639,7 +1639,7 @@ end function
 		rec_cnt -= 1
 
 		if( proc <> NULL ) then
-			return FB_OVLPROC_HALFMATCH - FB_DATATYPE_STRUCT
+			return FB_OVLPROC_HALFMATCH - FB_DATATYPE_STRUCT * FB_OVLPROC_CONVSCALE
 		end if
 	end if
 #endmacro
@@ -1664,7 +1664,16 @@ end function
 		rec_cnt -= 1
 
 		if( proc <> NULL ) then
-			return FB_OVLPROC_HALFMATCH - FB_DATATYPE_STRUCT
+			'' calculate a new match score based on the CAST() return type rank
+			var match = typeCalcMatch( param_dtype, param_subtype, symbGetParamMode( param ), symbGetFullType( proc ), symbGetSubType( proc ) )
+
+			if( match >= FB_OVLPROC_TYPEMATCH ) then
+				return FB_OVLPROC_HALFMATCH - FB_DATATYPE_STRUCT * FB_OVLPROC_CONVSCALE + 2
+			elseif( match >= FB_OVLPROC_HALFMATCH ) then
+				return FB_OVLPROC_HALFMATCH - FB_DATATYPE_STRUCT * FB_OVLPROC_CONVSCALE + 1
+			end if
+
+			return FB_OVLPROC_HALFMATCH - FB_DATATYPE_STRUCT * FB_OVLPROC_CONVSCALE
 		end if
 	end if
 #endmacro
@@ -1821,9 +1830,13 @@ private function hCalcTypesDiff _
 		'' corresponding to hStrArgToStrPtrParam())
 		case FB_DATACLASS_STRING
 			select case param_dtype
-			case FB_DATATYPE_CHAR, typeAddrOf( FB_DATATYPE_CHAR )
+			case FB_DATATYPE_CHAR
 				return FB_OVLPROC_FULLMATCH
-			case FB_DATATYPE_WCHAR, typeAddrOf( FB_DATATYPE_WCHAR )
+			case typeAddrOf( FB_DATATYPE_CHAR )
+				return FB_OVLPROC_FULLMATCH
+			case FB_DATATYPE_WCHAR
+				return FB_OVLPROC_HALFMATCH
+			case typeAddrOf( FB_DATATYPE_WCHAR )
 				return FB_OVLPROC_HALFMATCH
 			end select
 

src/compiler/symb.bi

@@ -72,9 +72,10 @@ const FB_DT_MANGLEPOS		= 20
 enum FB_OVLPROC_MATCH_SCORE
 	FB_OVLPROC_NO_MATCH = 0
 	FB_OVLPROC_LOWEST_MATCH = 1
-	FB_OVLPROC_HALFMATCH = FB_DATATYPES
-	FB_OVLPROC_TYPEMATCH = FB_DATATYPES * 2
-	FB_OVLPROC_FULLMATCH = FB_DATATYPES * 3
+	FB_OVLPROC_CONVSCALE = 2
+	FB_OVLPROC_HALFMATCH = FB_DATATYPES * 1 * FB_OVLPROC_CONVSCALE
+	FB_OVLPROC_TYPEMATCH = FB_DATATYPES * 2 * FB_OVLPROC_CONVSCALE
+	FB_OVLPROC_FULLMATCH = FB_DATATYPES * 3 * FB_OVLPROC_CONVSCALE
 end enum
 
 enum

tests/udt-zstring/left.bas

@@ -29,6 +29,10 @@ SUITE( fbc_tests.udt_zstring_.left_ )
 		next
 	#endmacro
 
+#if ENABLE_CHECK_BUGS
+
+'' left and right functions are not overloaded to accept a BYREF as ZSTRING
+
 	TEST( default )
 
 		check( "" )
@@ -37,4 +41,6 @@ SUITE( fbc_tests.udt_zstring_.left_ )
 		check( "1234567890" )
 	END_TEST
 
+#endif
+
 END_SUITE