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Default Parameters - Quick Question
#4
That's why I introduced so called TagStrings for my GuiTools Framework. However, the required include files have no direct dependncies on the Framework and can be easily used standalone, see the short example below. The functions are documented briefly, if you're interested in the whole story, then download the Framework and look into the GuiTools PDF documentation.

This form of parametering of course involves more writing, but has several advantages such as variable argument lists and default values. Also when evolving your program you never run into "wrong argument count" errors, because you added a new argument to a SUB/FUNC but forgot to change all calls to it. With Tag Strings you would simply add a new Tag instead, but the FUNC Xxx (tags$) reamains the same.

DefArg.bas
Code: (Select All)
'$INCLUDE: 'TagSupport.bi'

DefOrNotDef NewTag$("TEXT", "This is my given text with default colors.")
DefOrNotDef NewTag$("TEXT", "This is my given text on red background.") +_
            NewTag$("BGCOLOR", "4")
DefOrNotDef NewTag$("FGCOLOR", "12") 'default text in bright red
END

SUB DefOrNotDef (tags$)
fg% = VAL(GetTagData$(tags$, "FGCOLOR", "15"))
bg% = VAL(GetTagData$(tags$, "BGCOLOR", "0"))
tx$ = GetTagData$(tags$, "TEXT", "Default text")
COLOR fg%, bg%
PRINT tx$
END SUB

'$INCLUDE: 'TagSupport.bm'

TagSupport.bi
Code: (Select All)
'+---------------+---------------------------------------------------+
'| ###### ###### | .--. . .-. |
'| ## ## ## # | | )| ( ) o |
'| ## ## ## | |--' |--. .-. `-. . .-...--.--. .-. |
'| ###### ## | | \ | |( )( ) | ( || | |( ) |
'| ## ## | ' `' `-`-' `-'-' `-`-`|' ' `-`-'`- |
'| ## ## # | ._.' |
'| ## ###### | Sources & Documents placed under the MIT License. |
'+---------------+---------------------------------------------------+
'| |
'| === TagSupport.bi === |
'| |
'| == This include file is part of the GuiTools Framework Project. |
'| == It provides some constants needed for the Tag Strings API. |
'| |
'+-------------------------------------------------------------------+
'| Done by RhoSigma, R.Heyder, provided AS IS, use at your own risk. |
'| Find me in the QB64 Forum or mail to support@rhosigma-cw.net for |
'| any questions or suggestions. Thanx for your interest in my work. |
'+-------------------------------------------------------------------+

'-----------------------------
'--- Various tag constants ---
'-----------------------------
'--- These constants define the tokens used to uniquely identify single
'--- tags within a tag string. There's also an CHR$(0) replacement, which
'--- is used internally to allow C/C++ level operations without problems.
'--- The used control chars (ASCII 28-31) do not conflict with regular
'--- tag data writings nor with Ctrl shortcut sequences.
'-----
CONST tagIntr$ = CHR$(30) 'tag item introducer
CONST tagSepa$ = CHR$(29) 'tag name <-> tag data separator
CONST tagTerm$ = CHR$(31) 'tag item terminator
CONST tagRepl$ = CHR$(28) 'tag item CHR$(0) replacement

TagSupport.bm
Code: (Select All)
'+---------------+---------------------------------------------------+
'| ###### ###### | .--. . .-. |
'| ## ## ## # | | )| ( ) o |
'| ## ## ## | |--' |--. .-. `-. . .-...--.--. .-. |
'| ###### ## | | \ | |( )( ) | ( || | |( ) |
'| ## ## | ' `' `-`-' `-'-' `-`-`|' ' `-`-'`- |
'| ## ## # | ._.' |
'| ## ###### | Sources & Documents placed under the MIT License. |
'+---------------+---------------------------------------------------+
'| |
'| === TagSupport.bm === |
'| |
'| == This include file is part of the GuiTools Framework Project. |
'| == It provides the SUBs and FUNCTIONs of the Tag Strings API. |
'| |
'+-------------------------------------------------------------------+
'| Done by RhoSigma, R.Heyder, provided AS IS, use at your own risk. |
'| Find me in the QB64 Forum or mail to support@rhosigma-cw.net for |
'| any questions or suggestions. Thanx for your interest in my work. |
'+-------------------------------------------------------------------+

'-------------------------------
'--- Tag String API routines ---
'-------------------------------
'--- Always use these routines to create and manipulate any tags and/or
'--- tag strings, never write any tags or tag strings as literals, even
'--- if you know the used introducer/separator and terminator tokens.
'--- Follow this rule even if it's hard, seems to be overkill in some
'--- situations and does require a lot more writing, it will ensure the
'--- integrity of the tag API and will make future changes less painful.
'-----
'--- Note that many of the following SUBs and FUNCTIONs will have a side
'--- effect on the given tagString$ argument. It's done so by intention.
'--- Note also, that the tagName$ is mandatory where used, otherwise the
'--- whole thing wouldn't make any sense at all. In fact, be prepared for
'--- any kind of misbehavior you can imagine, if you fail to provide a
'--- proper tagName$. All upper/lower case mess and/or whitespace crap is
'--- handled internally as good as possible.

'---------------------------------------------------------------------
'Add a new tag to the tag string. Note this routine is internal, you
'should always use SetTag instead to avoid multiple tags of the same
'name get added to the tag string.
SUB AddTag (tagString$, tagName$, tagData$)
tagString$ = tagString$ + tagIntr$ + UCASE$(LTRIM$(RTRIM$(FilterChars$(tagName$, "")))) + tagSepa$ + FilterChars$(tagData$, " ") + tagTerm$
END SUB

'---------------------------------------------------------------------
'Search given tag and remove it from the tag string. Will do nothing,
'if the tag does not exist in the tag string.
SUB RemTag (tagString$, tagName$)
bra% = INSTR(tagString$, tagIntr$ + UCASE$(LTRIM$(RTRIM$(FilterChars$(tagName$, "")))) + tagSepa$)
IF bra% > 0 THEN
ket% = INSTR(bra% + 1, tagString$, tagTerm$)
IF ket% > 0 THEN
tagString$ = LEFT$(tagString$, bra% - 1) + MID$(tagString$, ket% + 1)
END IF
END IF
END SUB

'---------------------------------------------------------------------
'Same as RemTag, but used to remove many tags according to the given
'(comma separated) list of tag names. Can remove a single tag too,
'although RemTag would be more efficient in that case.
SUB RemTags (tagString$, remNames$)
tmpRemNames$ = LTRIM$(RTRIM$(remNames$))
IF LEFT$(tmpRemNames$, 1) = "," THEN tmpRemNames$ = MID$(tmpRemNames$, 2)
IF RIGHT$(tmpRemNames$, 1) <> "," THEN tmpRemNames$ = tmpRemNames$ + ","
ket% = 0
DO
bra% = ket% + 1
ket% = INSTR(bra%, tmpRemNames$, ",")
IF ket% > bra% THEN
remName$ = LTRIM$(RTRIM$(MID$(tmpRemNames$, bra%, ket% - bra%)))
IF remName$ <> "" THEN RemTag tagString$, remName$
END IF
LOOP WHILE ket% > 0
END SUB

'---------------------------------------------------------------------
'Set data of the given tag in the tag string. Will add a new tag, if
'the named tag does not exist yet in the tag string.
SUB SetTag (tagString$, tagName$, newData$)
RemTag tagString$, tagName$
AddTag tagString$, tagName$, newData$
END SUB

'---------------------------------------------------------------------
'Will return a boolean value according to the check whether all given
'tags (comma separated list of tag names) exist in the tag string and
'also have valid (non-empty) data. May also remove any invalid tags
'upon request (remInvalid% = true (non-zero)). Will always return true,
'if no tag names to check are specified.
FUNCTION ValidateTags% (tagString$, chkNames$, remInvalid%)
ValidateTags% = -1
tmpChkNames$ = LTRIM$(RTRIM$(chkNames$))
IF LEFT$(tmpChkNames$, 1) = "," THEN tmpChkNames$ = MID$(tmpChkNames$, 2)
IF RIGHT$(tmpChkNames$, 1) <> "," THEN tmpChkNames$ = tmpChkNames$ + ","
ket% = 0
DO
bra% = ket% + 1
ket% = INSTR(bra%, tmpChkNames$, ",")
IF ket% > bra% THEN
chkName$ = LTRIM$(RTRIM$(MID$(tmpChkNames$, bra%, ket% - bra%)))
IF chkName$ <> "" THEN
IF GetTagData$(tagString$, chkName$, "n/a") = "n/a" THEN
ValidateTags% = 0
IF remInvalid% <> 0 THEN
RemTag tagString$, chkName$
ELSE
EXIT FUNCTION
END IF
END IF
END IF
END IF
LOOP WHILE ket% > 0
END FUNCTION

'---------------------------------------------------------------------
'Create a new tag. Similar to AddTag, but this will just return the new
'tag instead of adding it to any tag string.
FUNCTION NewTag$ (tagName$, tagData$)
NewTag$ = tagIntr$ + UCASE$(LTRIM$(RTRIM$(FilterChars$(tagName$, "")))) + tagSepa$ + FilterChars$(tagData$, " ") + tagTerm$
END FUNCTION

'---------------------------------------------------------------------
'Search given tag in the tag string and return it. Will return empty,
'if the tag does not exist in the tag string. Note that a found tag is
'not checked for validity, it's returned as it is in the tag string.
FUNCTION GetTag$ (tagString$, tagName$)
GetTag$ = ""
bra% = INSTR(tagString$, tagIntr$ + UCASE$(LTRIM$(RTRIM$(FilterChars$(tagName$, "")))) + tagSepa$)
IF bra% > 0 THEN
ket% = INSTR(bra% + 1, tagString$, tagTerm$)
IF ket% > 0 THEN
GetTag$ = MID$(tagString$, bra%, ket% - bra% + 1)
END IF
END IF
END FUNCTION

'---------------------------------------------------------------------
'Same as GetTag$, but used to get many tags according to the given
'(comma separated) list of tag names. Can return a single tag too,
'although GetTag$ would be more efficient in that case.
FUNCTION GetTags$ (tagString$, getNames$)
tags$ = ""
tmpGetNames$ = LTRIM$(RTRIM$(getNames$))
IF LEFT$(tmpGetNames$, 1) = "," THEN tmpGetNames$ = MID$(tmpGetNames$, 2)
IF RIGHT$(tmpGetNames$, 1) <> "," THEN tmpGetNames$ = tmpGetNames$ + ","
ket% = 0
DO
bra% = ket% + 1
ket% = INSTR(bra%, tmpGetNames$, ",")
IF ket% > bra% THEN
getName$ = LTRIM$(RTRIM$(MID$(tmpGetNames$, bra%, ket% - bra%)))
IF getName$ <> "" THEN tags$ = tags$ + GetTag$(tagString$, getName$)
END IF
LOOP WHILE ket% > 0
GetTags$ = tags$
END FUNCTION

'---------------------------------------------------------------------
'Search given tag in the tag string, return it and also remove it from
'the tag string. Will return empty and remove nothing, if the tag does
'not exist in the tag string. Note that a found tag is not checked for
'validity, it's returned as it was in the tag string before removal.
'Used in conjunction with GetTagName$ to process (unknown) user tags.
FUNCTION ExtractTag$ (tagString$, tagName$)
ExtractTag$ = GetTag$(tagString$, tagName$)
RemTag tagString$, tagName$
END FUNCTION

'---------------------------------------------------------------------
'Look for the first tag in the tag string and return its name. Will
'return empty, if no tags exist in the tag string. Used in conjunction
'with ExtractTag$ to process (unknown) user tags.
FUNCTION GetTagName$ (tagString$)
GetTagName$ = ""
bra% = INSTR(tagString$, tagIntr$)
IF bra% > 0 THEN
ket% = INSTR(bra% + 1, tagString$, tagSepa$)
IF ket% > 0 THEN
IF ket% > (bra% + 1) THEN 'ket% must be after tag name start
GetTagName$ = MID$(tagString$, bra% + 1, ket% - bra% - 1)
END IF
END IF
END IF
END FUNCTION

'---------------------------------------------------------------------
'Search given tag in the tag string and return its associated data.
'If the tag does not exist or appears to be invalid, then return the
'provided default data instead.
FUNCTION GetTagData$ (tagString$, tagName$, defData$)
dat$ = defData$
tmpTagName$ = UCASE$(LTRIM$(RTRIM$(FilterChars$(tagName$, ""))))
bra% = INSTR(tagString$, tagIntr$ + tmpTagName$ + tagSepa$)
IF bra% > 0 THEN
ket% = INSTR(bra% + 1, tagString$, tagTerm$)
bra% = bra% + LEN(tmpTagName$) + 2
IF ket% > 0 THEN
IF ket% > bra% THEN 'ket% must be after tagIntr$+tagName$+tagSepa$
dat$ = MID$(tagString$, bra%, ket% - bra%)
FOR i% = 1 TO LEN(dat$)
IF MID$(dat$, i%, 1) = tagRepl$ THEN MID$(dat$, i%, 1) = CHR$(0)
NEXT i%
END IF
END IF
END IF
GetTagData$ = dat$
END FUNCTION

'---------------------------------------------------------------------
'Search given tag in both, new and old tag strings and update its data
'from new to old string, if the data is different or the named tag does
'not even exist yet in the old string. Will return true, if the old
'string had to be updated, or false, if the tag its data were either
'equal in both (old/new) tag strings or the given tag did not even exist
'in the new tag string.
FUNCTION UpdateTag% (oldTagString$, tagName$, newTagString$)
UpdateTag% = 0
ndat$ = GetTagData$(newTagString$, tagName$, "n/a")
IF ndat$ <> "n/a" THEN
odat$ = GetTagData$(oldTagString$, tagName$, "n/a")
IF ndat$ <> odat$ THEN
SetTag oldTagString$, tagName$, ndat$
UpdateTag% = -1
END IF
END IF
END FUNCTION

'---------------------------------------------------------------------
'Same as UpdateTag%, but used to update many tags according to the given
'(comma separated) list of tag names. This function will return true, if
'at least one of the given tags had to be updated, otherwise it's false.
'Can update a single tag too, although UpdateTag% would be more efficient
'in that case.
FUNCTION UpdateTags% (oldTagString$, updNames$, newTagString$)
UpdateTags% = 0
tmpUpdNames$ = LTRIM$(RTRIM$(updNames$))
IF LEFT$(tmpUpdNames$, 1) = "," THEN tmpUpdNames$ = MID$(tmpUpdNames$, 2)
IF RIGHT$(tmpUpdNames$, 1) <> "," THEN tmpUpdNames$ = tmpUpdNames$ + ","
ket% = 0
DO
bra% = ket% + 1
ket% = INSTR(bra%, tmpUpdNames$, ",")
IF ket% > bra% THEN
updName$ = LTRIM$(RTRIM$(MID$(tmpUpdNames$, bra%, ket% - bra%)))
IF updName$ <> "" THEN
IF UpdateTag%(oldTagString$, updName$, newTagString$) THEN UpdateTags% = -1
END IF
END IF
LOOP WHILE ket% > 0
END FUNCTION

'---------------------------------------------------------------------
'Will return a boolean value according to the check whether the given
'boolean tag in the tag string is true (tag found and data is numeric
'non-zero or string "true"/"yes"/"on") or false (tag not found or data
'is numeric zero or not string "true"/"yes"/"on").
FUNCTION BoolTagTrue% (tagString$, tagName$)
tmpData$ = LCASE$(LTRIM$(RTRIM$(GetTagData$(tagString$, tagName$, "0"))))
IF VAL(tmpData$) <> 0 OR tmpData$ = "true" OR tmpData$ = "yes" OR tmpData$ = "on" THEN
BoolTagTrue% = -1
ELSE
BoolTagTrue% = 0
END IF
END FUNCTION

'---------------------------------------------------------------------
'Toggle the state of the given boolean tag in the tag string and return
'a boolean value according to the tag its new state.
FUNCTION ToggleBoolTag% (tagString$, tagName$)
tmpData$ = LCASE$(LTRIM$(RTRIM$(GetTagData$(tagString$, tagName$, "0"))))
IF VAL(tmpData$) <> 0 OR tmpData$ = "true" OR tmpData$ = "yes" OR tmpData$ = "on" THEN
RemTag tagString$, tagName$
ToggleBoolTag% = 0
ELSE
SetTag tagString$, tagName$, "true"
ToggleBoolTag% = -1
END IF
END FUNCTION

'--- INTERNAL --------------------------------------------------------
'This function will filter any tag introducer/separator and terminator
'tokens (as defined in TagSupport.bi) from any given tag names and data.
'It's used to ensure the uniqueness of these chars, hence the integrity
'of the entire Tag Strings API.
FUNCTION FilterChars$ (tnod$, exg$)
$CHECKING:OFF
temp$ = tnod$
char$ = tagIntr$: GOSUB fcFilter
char$ = tagSepa$: GOSUB fcFilter
char$ = tagTerm$: GOSUB fcFilter
char$ = CHR$(0): exg2$ = tagRepl$: SWAP exg$, exg2$: GOSUB fcFilter: SWAP exg$, exg2$
FilterChars$ = temp$
IF exg$ <> "" THEN EXIT FUNCTION
'do the following for tag names only (checked by exg$ contents, which is
'empty for tag names)
char$ = ",": GOSUB fcFilter
char$ = CHR$(9): GOSUB fcFilter
char$ = CHR$(32): GOSUB fcFilter
FilterChars$ = temp$
EXIT FUNCTION
'----------------
fcFilter:
bra% = 1
DO
bra% = INSTR(bra%, temp$, char$)
IF bra% > 0 THEN temp$ = LEFT$(temp$, bra% - 1) + exg$ + MID$(temp$, bra% + 1)
LOOP WHILE bra% > 0
RETURN
$CHECKING:ON
END FUNCTION
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RE: Default Parameters - Quick Question - by RhoSigma - 11-12-2023, 04:35 PM



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