Addition of precompiler into QB64 via $LET, $IF, $ELSEIF, $ELSE, $END IF commands.

source/ide/ide_methods.bas

@@ -6246,6 +6246,8 @@ FOR y = 0 TO (idewy - 9)
         ELSEIF inquote OR MID$(a2$, m, 1) = CHR$(34) THEN
             COLOR 14
         END IF
+        If InValidLine(l) and 1 then color 7
+
         LOCATE y + 3, 2 + m - 1
         PRINT MID$(a2$, m, 1);
     NEXT m

source/qb64.bas

@@ -26,6 +26,21 @@ Set_OrderOfOperations 'This will also make certain our directories are valid, an
 DIM SHARED MakeAndroid 'build an Android project (refer to SUB UseAndroid)
 
 REDIM EveryCaseSet(100), SelectCaseCounter AS _UNSIGNED LONG
+DIM ExecLevel(255), ExecCounter AS INTEGER
+REDIM SHARED UserDefine(1, 100) AS STRING '0 element is the name, 1 element is the string value
+REDIM SHARED InValidLine(10000) AS _BIT
+DIM DefineElse(255) AS _BYTE
+DIM SHARED UserDefineCount AS INTEGER
+UserDefine(0, 0) = "WINDOWS": UserDefine(0, 1) = "WIN"
+UserDefine(0, 2) = "LINUX"
+UserDefine(0, 3) = "MAC": UserDefine(0, 4) = "MACOSX"
+UserDefine(0, 5) = "32BIT": UserDefine(0, 6) = "64BIT"
+IF INSTR(_OS$, "WIN") THEN UserDefine(1, 0) = "-1": UserDefine(1, 1) = "-1" ELSE UserDefine(1, 0) = "0": UserDefine(1, 1) = "0"
+IF INSTR(_OS$, "LINUX") THEN UserDefine(1, 2) = "-1" ELSE UserDefine(1, 2) = "0"
+IF INSTR(_OS$, "MAC") THEN UserDefine(1, 3) = "-1": UserDefine(1, 4) = "-1" ELSE UserDefine(1, 3) = "0": UserDefine(1, 4) = "0"
+IF INSTR(_OS$, "32BIT") THEN UserDefine(1, 5) = "-1": UserDefine(1, 6) = "0" ELSE UserDefine(1, 5) = "0": UserDefine(1, 6) = "-1"
+
+
 
 'refactor patch
 DIM SHARED Refactor_Source AS STRING
@@ -1336,6 +1351,9 @@ stringprocessinghappened = 0
 subfuncn = 0
 subfunc = ""
 SelectCaseCounter = 0
+ExecCounter = 0
+UserDefineCount = 6
+REDIM SHARED InValidLine(10000) AS _BIT
 
 ''create a type for storing memory blocks
 ''UDT
@@ -1490,11 +1508,144 @@ layout = ""
     layoutok = 0
 
     linenumber = linenumber + 1
+
+    IF linenumber > UBOUND(InValidLine) THEN REDIM _PRESERVE InValidLine(UBOUND(InValidLine) + 1000) AS _BIT 'color information flag for each line
+    InValidLine(linenumber) = 0
+
     IF LEN(wholeline$) THEN
 
         wholeline$ = lineformat(wholeline$)
         IF Error_Happened THEN GOTO errmes
 
+        temp$ = LTRIM$(RTRIM$(UCASE$(wholestv$)))
+
+        IF LEFT$(temp$, 5) = "$LET " THEN
+            temp$ = LTRIM$(MID$(temp$, 5)) 'simply shorten our string to parse
+            'For starters, let's make certain that we have 3 elements to deal with
+            temp = INSTR(temp$, "=") 'without an = in there, we can't get a value from the left and right side
+            IF temp = 0 THEN a$ = "Invalid Syntax.  $LET <flag> = <value>": GOTO errmes
+            l$ = RTRIM$(LEFT$(temp$, temp - 1)): r$ = LTRIM$(MID$(temp$, temp + 1))
+            'then validate to make certain the left side looks proper
+            l1$ = ""
+            FOR i = 1 TO LEN(l$)
+                a = ASC(l$, i)
+                SELECT CASE a
+                    CASE 32 'strip out spaces
+                    CASE 46: l1$ = l1$ + CHR$(a)
+                    CASE IS < 48, IS > 90: a$ = "Invalid symbol left of equal sign (" + CHR$(a) + ")": GOTO errmes
+                    CASE ELSE: l1$ = l1$ + CHR$(a)
+                END SELECT
+            NEXT
+            l$ = l1$
+            IF LEFT$(r$, 1) = CHR$(34) THEN r$ = LTRIM$(MID$(r$, 2))
+            IF RIGHT$(r$, 1) = CHR$(34) THEN r$ = RTRIM$(LEFT$(r$, LEN(r$) - 1))
+            IF LEFT$(r$, 1) = "-" THEN
+                r1$ = "-"
+                r$ = LTRIM$(MID$(r$, 2))
+            ELSE
+                r1$ = ""
+            END IF
+            'then validate to make certain the left side looks proper
+            FOR i = 1 TO LEN(r$)
+                a = ASC(r$, i)
+                SELECT CASE a
+                    CASE 32
+                    CASE 46 'periods are fine.
+                        r1$ = r1$ + "."
+                    CASE IS < 48, IS > 90
+                        a$ = "Invalid symbol right of equal sign (" + CHR$(a) + ")": GOTO errmes
+                    CASE ELSE
+                        r1$ = r1$ + CHR$(a)
+                END SELECT
+            NEXT
+            r$ = r1$
+            layout$ = "$LET " + l$ + " = " + r$
+            'First look to see if we have an existing setting like this and if so, update it
+            FOR i = 7 TO UserDefineCount 'UserDefineCount 1-6 are reserved for automatic OS/BIT detection
+                IF UserDefine(0, i) = l$ THEN UserDefine(1, i) = r$: GOTO finishedlinepp
+            NEXT
+            'Otherwise create a new setting and set the initial value for it
+            UserDefineCount = UserDefineCount + 1
+            IF UserDefineCount > UBOUND(UserDefine, 2) THEN
+                REDIM _PRESERVE UserDefine(1, UBOUND(UserDefine, 2) + 10) 'Add another 10 elements to the array so it'll expand as the user adds to it
+            END IF
+            UserDefine(0, UserDefineCount) = l$
+            UserDefine(1, UserDefineCount) = r$
+            GOTO finishedlinepp
+        END IF
+
+
+        IF LEFT$(temp$, 4) = "$IF " THEN
+            IF RIGHT$(temp$, 5) <> " THEN" THEN a$ = "$IF without THEN": GOTO errmes
+            temp$ = LTRIM$(MID$(temp$, 4)) 'strip off the $IF and extra spaces
+            temp$ = RTRIM$(LEFT$(temp$, LEN(temp$) - 4)) 'and strip off the THEN and extra spaces
+            temp = INSTR(temp$, "=")
+            ExecCounter = ExecCounter + 1
+            ExecLevel(ExecCounter) = -1 'default to a skip value
+            DefineElse(ExecCounter) = 1 '1 says we have an $IF statement at this level
+            result = EvalPreIF(temp$, a$)
+            IF a$ <> "" THEN GOTO errmes
+            IF result <> 0 THEN
+                ExecLevel(ExecCounter) = ExecLevel(ExecCounter - 1) 'So we inherit the execlevel from above
+                IF ExecLevel(ExecCounter) = 0 THEN DefineElse(ExecCounter) = DefineElse(ExecCounter) OR 4 'Else if used and conditon found
+            END IF
+            GOTO finishedlinepp 'and then we're finished -- and at this point we didn't make a match so we exit with a DONT READ type flag on our code.
+        END IF
+
+        IF temp$ = "$ELSE" THEN
+            IF DefineElse(ExecCounter) = 0 THEN a$ = "$ELSE without $IF": GOTO errmes
+            IF DefineElse(ExecCounter) AND 2 THEN a$ = "$IF block already has $ELSE statement in it": GOTO errmes
+            DefineElse(ExecCounter) = DefineElse(ExecCounter) OR 2 'set the flag to declare an $ELSE already in this block
+            IF DefineElse(ExecCounter) AND 4 THEN 'If we executed code in a previous IF or ELSE IF statement, we can't do it here
+                ExecLevel(ExecCounter) = -1 'So we inherit the execlevel from above
+            ELSE
+                ExecLevel(ExecCounter) = ExecLevel(ExecCounter - 1) 'If we were processing code before, code after this segment is going to be SKIPPED
+            END IF
+            GOTO finishedlinepp
+        END IF
+
+        IF LEFT$(temp$, 5) = "$ELSE" THEN 'looking for $ELSE IF
+            temp$ = LTRIM$(MID$(temp$, 6))
+            IF LEFT$(temp$, 3) = "IF " THEN
+                IF DefineElse(ExecCounter) = 0 THEN a$ = "$ELSE IF without $IF": GOTO errmes
+                IF DefineElse(ExecCounter) AND 2 THEN a$ = "$ELSE IF cannot follow $ELSE": GOTO errmes
+                IF RIGHT$(temp$, 5) <> " THEN" THEN a$ = "$ELSE IF without THEN": GOTO errmes
+                IF DefineElse(ExecCounter) AND 4 THEN 'If we executed code in a previous IF or ELSE IF statement, we can't do it here
+                    ExecLevel(ExecCounter) = -1
+                    GOTO finishedlinepp
+                END IF
+                temp$ = LTRIM$(MID$(temp$, 3)) 'strip off the IF and extra spaces
+                temp$ = RTRIM$(LEFT$(temp$, LEN(temp$) - 4)) 'and strip off the THEN and extra spaces
+                result = EvalPreIF(temp$, a$)
+                IF a$ <> "" THEN GOTO errmes
+                IF result <> 0 THEN
+                    ExecLevel(ExecCounter) = ExecLevel(ExecCounter - 1) 'So we inherit the execlevel from above
+                    IF ExecLevel(ExecCounter) = 0 THEN DefineElse(ExecCounter) = DefineElse(ExecCounter) OR 4 'Else if used and conditon found
+                END IF
+                GOTO finishedlinepp 'and then we're finished -- and at this point we didn't make a match so we exit with a DONT READ type flag on our code.
+            END IF
+        END IF
+
+
+
+        IF temp$ = "$END IF" OR temp$ = "$ENDIF" THEN
+            IF DefineElse(ExecCounter) = 0 THEN a$ = "$END IF without $IF": GOTO errmes
+            DefineElse(ExecCounter) = 0 'We no longer have an $IF block at this level
+            ExecCounter = ExecCounter - 1
+            GOTO finishedlinepp
+        END IF
+
+
+
+        IF ExecLevel(ExecCounter) THEN
+            IF linenumber > UBOUND(InValidLine) THEN REDIM _PRESERVE InValidLine(UBOUND(InValidLine) + 10000) AS _BIT
+            InValidLine(linenumber) = -1
+            GOTO finishedlinepp 'we don't check for anything inside lines that we've marked for skipping
+        END IF
+
+
+
+
         cwholeline$ = wholeline$
         wholeline$ = eleucase$(wholeline$) '********REMOVE THIS LINE LATER********
 
@@ -2534,6 +2685,12 @@ IF idemode = 0 AND inclevel = 0 THEN a3$ = lineinput3$
     IF a3$ = CHR$(13) THEN EXIT DO
     linenumber = linenumber + 1
 
+    IF InValidLine(linenumber) THEN
+        layoutok = 1
+        layout$ = SPACE$(controllevel) + LTRIM$(RTRIM$(a3$))
+        IF idemode GOTO ideret4 ELSE GOTO skipide4
+    END IF
+
     layout = ""
     layoutok = 1
 
@@ -2556,6 +2713,10 @@ IF Debug THEN PRINT #9, "########" + a3$ + "########"
 
     layoutdone = 1 'validates layout of any following goto finishednonexec/finishedline
 
+    'We've already figured out in the prepass which lines are invalidated by the precompiler
+    'No need to go over those lines again.
+    'IF InValidLine(linenumber) THEN goto skipide4 'layoutdone = 0: GOTO finishednonexec
+
     'QB64 Metacommands
     IF ASC(a3$) = 36 THEN '$
 
@@ -2626,10 +2787,54 @@ Resize = 1: Resize_Scale = 2
             GOTO finishednonexec
         END IF
 
+        IF LEFT$(a3u$, 5) = "$LET " THEN GOTO finishednonexec 'we dealt with this basically in the prepass
+        '                   so we could define CONST and such and have them available for later IDE passes
+
+        IF a3u$ = "$END IF" OR a3u$ = "$ENDIF" THEN
+            layout$ = "$END IF"
+            controltype(controllevel) = 0
+            controllevel = controllevel - 1
+            GOTO finishednonexec
+        END IF
+
+        IF LEFT$(a3u$, 4) = "$IF " THEN
+            temp$ = LTRIM$(MID$(a3u$, 4)) 'strip off the $IF and extra spaces
+            temp$ = RTRIM$(LEFT$(temp$, LEN(temp$) - 4)) 'and strip off the THEN and extra spaces
+            temp = INSTR(temp$, "=")
+            controllevel = controllevel + 1
+            controltype(controllevel) = 6
+            IF temp = 0 THEN layout$ = "$IF " + temp$ + " THEN": GOTO finishednonexec 'no = sign in the $IF statement, so we're going to assume the user is doing something like $IF flag
+            l$ = RTRIM$(LEFT$(temp$, temp - 1)): r$ = LTRIM$(MID$(temp$, temp + 1))
+            layout$ = "$IF " + l$ + " = " + r$ + " THEN"
+            GOTO finishednonexec
+        END IF
+
+        IF a3u$ = "$ELSE" THEN
+            layout$ = "$ELSE"
+            lhscontrollevel = lhscontrollevel - 1
+            GOTO finishednonexec
+        END IF
+
+        IF LEFT$(a3u$, 5) = "$ELSE" THEN
+            temp$ = LTRIM$(MID$(a3u$, 6))
+            IF LEFT$(temp$, 3) = "IF " THEN
+                lhscontrollevel = lhscontrollevel - 1
+                temp$ = LTRIM$(MID$(temp$, 3)) 'strip off the IF and extra spaces
+                temp$ = RTRIM$(LEFT$(temp$, LEN(temp$) - 4)) 'and strip off the THEN and extra spaces
+                temp = INSTR(temp$, "=")
+                IF temp = 0 THEN layout$ = "$ELSE IF " + temp$ + " THEN": GOTO finishednonexec 'no = sign in the $IF statement, so we're going to assume the user is doing something like $IF flag
+                l$ = RTRIM$(LEFT$(temp$, temp - 1)): r$ = LTRIM$(MID$(temp$, temp + 1))
+                layout$ = "$ELSE IF " + l$ + " = " + r$ + " THEN"
+                GOTO finishednonexec
+            END IF
+        END IF
+
 
 
     END IF 'QB64 Metacommands
 
+
+
     linedataoffset = DataOffset
 
     entireline$ = lineformat(a3$): IF LEN(entireline$) = 0 THEN GOTO finishednonexec
@@ -3926,7 +4131,7 @@ IF declaringlibrary THEN GOTO declibjmp1
             IF closedmain = 0 THEN closemain
 
             'check for open controls (copy #2)
-IF controllevel THEN
+            IF controllevel <> 0 AND controltype(controllevel) <> 6 THEN 'It's OK for subs to be inside $IF blocks
                 x = controltype(controllevel)
                 IF x = 1 THEN a$ = "IF without END IF"
                 IF x = 2 THEN a$ = "FOR without NEXT"
@@ -4404,7 +4609,7 @@ IF sf THEN
                 IF LEN(subfunc) = 0 THEN a$ = "END " + secondelement$ + " without " + secondelement$: GOTO errmes
 
                 'check for open controls (copy #3)
-IF controllevel THEN
+                IF controllevel <> 0 AND controltype(controllevel) <> 6 THEN 'It's OK for subs to be inside $IF blocks
                     x = controltype(controllevel)
                     IF x = 1 THEN a$ = "IF without END IF"
                     IF x = 2 THEN a$ = "FOR without NEXT"
@@ -9885,7 +10090,7 @@ GOTO ideret4 'return control to IDE
     END IF
 
     'layout is not currently used by the compiler (as appose to the IDE), if it was it would be used here
-
+    skipide4:
 LOOP
 
 ide5:
@@ -9898,10 +10103,12 @@ IF definingtype THEN linenumber = definingtypeerror: a$ = "TYPE without END TYPE
 'check for open controls (copy #1)
 IF controllevel THEN
     x = controltype(controllevel)
+    a$ = "Unidentified open control block"
     IF x = 1 THEN a$ = "IF without END IF"
     IF x = 2 THEN a$ = "FOR without NEXT"
     IF x = 3 OR x = 4 THEN a$ = "DO without LOOP"
     IF x = 5 THEN a$ = "WHILE without WEND"
+    IF x = 6 THEN a$ = "$IF without $END IF"
     IF (x >= 10 AND x <= 17) OR x = 18 OR x = 19 THEN a$ = "SELECT CASE without END SELECT"
     linenumber = controlref(controllevel)
     GOTO errmes
@@ -24008,6 +24215,180 @@ END IF
 END IF
 END FUNCTION
 
+FUNCTION EvalPreIF (text$, err$)
+temp$ = text$ 'so we don't corrupt the string sent to us for evaluation
+err$ = "" 'null the err message to begin with
+'first order of business is to solve for <>=
+DIM PC_Op(3) AS STRING
+PC_Op(1) = "="
+PC_Op(2) = "<"
+PC_Op(3) = ">"
+DO
+    'look for the existence of the first symbol if there is any
+    firstsymbol$ = "": first = 0
+    FOR i = 1 TO UBOUND(PC_Op)
+        temp = INSTR(temp$, PC_Op(i))
+        IF first = 0 THEN first = temp: firstsymbol$ = PC_Op(i)
+        IF temp <> 0 AND temp < first THEN first = temp: firstsymbol$ = PC_Op(i)
+    NEXT
+    IF firstsymbol$ <> "" THEN 'we've got = < >; let's see if we have a combination of them
+        secondsymbol = 0: second = 0
+        FOR i = first + 1 TO LEN(temp$)
+            a$ = MID$(temp$, i, 1)
+            SELECT CASE a$
+                CASE " " 'ignore spaces
+                CASE "=", "<", ">"
+                    IF a$ = firstsymbol$ THEN err$ = "Duplicate operator (" + a$ + ")": EXIT SUB
+                    second = i: secondsymbol$ = a$
+                CASE ELSE 'we found a symbol we don't recognize
+                    EXIT FOR
+            END SELECT
+        NEXT
+    END IF
+    IF first THEN 'we found a symbol
+        l$ = RTRIM$(LEFT$(temp$, first - 1))
+        IF second THEN rightstart = second + 1 ELSE rightstart = first + 1
+
+        r$ = LTRIM$(MID$(temp$, rightstart))
+        symbol$ = MID$(temp$, first, 1) + MID$(temp$, second, 1)
+        'now we check for spaces to separate this segment from any other AND/OR conditions and such
+        FOR i = LEN(l$) TO 1 STEP -1
+            IF ASC(l$, i) = 32 THEN EXIT FOR
+        NEXT
+        leftside$ = RTRIM$(LEFT$(temp$, i))
+        l$ = LTRIM$(RTRIM$(MID$(temp$, i + 1, LEN(l$) - i)))
+        rightstop = LEN(r$)
+        FOR i = 1 TO LEN(r$)
+            IF ASC(r$, i) = 32 THEN EXIT FOR
+        NEXT
+        rightside$ = LTRIM$(MID$(r$, i + 1))
+        r$ = LTRIM$(RTRIM$(LEFT$(r$, i - 1)))
+        IF symbol$ = "=<" THEN symbol$ = "<="
+        IF symbol$ = "=>" THEN symbol$ = ">="
+        IF symbol$ = "><" THEN symbol$ = "<>"
+        result$ = " 0 "
+        IF symbol$ = "<>" THEN 'check to see if we're NOT equal in any case with <>
+            FOR i = 0 TO UserDefineCount
+                IF UserDefine(0, i) = l$ AND UserDefine(1, i) <> r$ THEN result$ = " -1 ": GOTO finishedcheck
+            NEXT
+        END IF
+        IF INSTR(symbol$, "=") THEN 'check to see if we're equal in any case with =
+            FOR i = 0 TO UserDefineCount
+                IF UserDefine(0, i) = l$ AND UserDefine(1, i) = r$ THEN result$ = " -1 ": GOTO finishedcheck
+            NEXT
+        END IF
+
+        IF INSTR(symbol$, ">") THEN 'check to see if we're greater than in any case with >
+            FOR i = 0 TO UserDefineCount
+                IF VerifyNumber(r$) AND VerifyNumber(UserDefine(1, i)) THEN 'we're comparing numeric values
+                    IF UserDefine(0, i) = l$ AND VAL(UserDefine(1, i)) > VAL(r$) THEN result$ = " -1 ": GOTO finishedcheck
+                ELSE
+                    IF UserDefine(0, i) = l$ AND UserDefine(1, i) > r$ THEN result$ = " -1 ": GOTO finishedcheck
+                END IF
+            NEXT
+        END IF
+        IF INSTR(symbol$, "<") THEN 'check to see if we're less than in any case with <
+            FOR i = 0 TO UserDefineCount
+                IF VerifyNumber(r$) AND VerifyNumber(UserDefine(1, i)) THEN 'we're comparing numeric values
+                    IF UserDefine(0, i) = l$ AND VAL(UserDefine(1, i)) < VAL(r$) THEN result$ = " -1 ": GOTO finishedcheck
+                ELSE
+                    IF UserDefine(0, i) = l$ AND UserDefine(1, i) < r$ THEN result$ = " -1 ": GOTO finishedcheck
+                END IF
+            NEXT
+        END IF
+
+
+
+        finishedcheck:
+        temp$ = leftside$ + result$ + rightside$
+    END IF
+LOOP UNTIL first = 0
+
+'And at this point we should now be down to a statement with nothing but AND/OR/XORS in it
+
+PC_Op(1) = " AND "
+PC_Op(2) = " OR "
+PC_Op(3) = " XOR "
+
+DO
+    first = 0
+    FOR i = 1 TO UBOUND(PC_Op)
+        IF PC_Op(i) <> "" THEN
+            t = INSTR(temp$, PC_Op(i))
+            IF first <> 0 THEN
+                IF t < first AND t <> 0 THEN first = t: firstsymbol = i
+            ELSE
+                first = t: firstsymbol = i
+            END IF
+        END IF
+    NEXT
+    IF first = 0 THEN EXIT DO
+    leftside$ = RTRIM$(LEFT$(temp$, first - 1))
+    symbol$ = MID$(temp$, first, LEN(PC_Op(firstsymbol)))
+    t$ = MID$(temp$, first + LEN(PC_Op(firstsymbol)))
+    t = INSTR(t$, " ") 'the first space we come to
+    IF t THEN
+        m$ = LTRIM$(RTRIM$(LEFT$(t$, t - 1)))
+        rightside$ = LTRIM$(MID$(t$, t))
+    ELSE
+        m$ = LTRIM$(MID$(t$, t))
+        rightside$ = ""
+    END IF
+    leftresult = 0
+    IF VerifyNumber(leftside$) THEN
+        IF VAL(leftside$) <> 0 THEN leftresult = -1
+    ELSE
+        FOR i = 0 TO UserDefineCount
+            IF UserDefine(0, i) = leftside$ THEN
+                t$ = LTRIM$(RTRIM$(UserDefine(1, i)))
+                IF t$ <> "0" AND t$ <> "" THEN leftresult = -1: EXIT FOR
+            END IF
+        NEXT
+    END IF
+    rightresult = 0
+    IF VerifyNumber(m$) THEN
+        IF VAL(m$) <> 0 THEN rightresult = -1
+    ELSE
+        FOR i = 0 TO UserDefineCount
+            IF UserDefine(0, i) = m$ THEN
+                t$ = LTRIM$(RTRIM$(UserDefine(1, i)))
+                IF t$ <> "0" AND t$ <> "" THEN rightresult = -1: EXIT FOR
+            END IF
+        NEXT
+    END IF
+    SELECT CASE LTRIM$(RTRIM$(symbol$))
+        CASE "AND"
+            IF leftresult <> 0 AND rightresult <> 0 THEN result$ = " -1 " ELSE result$ = " 0 "
+        CASE "OR"
+            IF leftresult <> 0 OR rightresult <> 0 THEN result$ = " -1 " ELSE result$ = " 0 "
+        CASE "XOR"
+            IF leftresult <> rightresult THEN result$ = " -1 " ELSE result$ = " 0 "
+    END SELECT
+    temp$ = result$ + rightside$
+LOOP
+
+IF VerifyNumber(temp$) THEN
+    EvalPreIF = VAL(temp$)
+ELSE
+    IF INSTR(temp$, " ") THEN err$ = "Invalid Resolution of $IF; check statements" 'If we've got more than 1 statement, it's invalid
+    FOR i = 0 TO UserDefineCount
+        IF UserDefine(0, i) = temp$ THEN
+            t$ = LTRIM$(RTRIM$(UserDefine(1, i)))
+            IF t$ <> "0" AND t$ <> "" THEN EvalPreIF = -1: EXIT FOR
+        END IF
+    NEXT
+END IF
+
+END SUB
+
+FUNCTION VerifyNumber (text$)
+t$ = LTRIM$(RTRIM$(text$))
+v = VAL(t$)
+t1$ = LTRIM$(STR$(v))
+IF t$ = t1$ THEN VerifyNumber = -1
+END FUNCTION
+
+
 
 '$INCLUDE:'subs_functions\extensions\opengl\opengl_methods.bas'