Title: Tagged Command Line Parameters
Question: I needed a flexible way to handle command line parameters. The standard Delphi ParamStr() and FindCmdLineSwitch were not flexible enough as I needed parameter values to be in any order.
The FindCmdLineSwitch was not capable of this because a perfect match is searched for ie. /dsn=oracle1 or /dsn oracle1 would fail, as in the first case searching for
FindCmdLineSwitch('dsn',['-','/'],true) would result in false
as "dsn=oracle1" is the switch. In the second case the search would resolve to true, but the second part of the switch is a completely separate parameter and might or might not be a part of /dsn.
I decided to use Tagged Parameter values to solve the value problem
eg. dsn=oracle1 pass=fred123 {values bound to a param tag}
and use FindCmdLineSwitch for simple boolean switches
eg. /auto -auto etc. {switch present true or false}
Using a simple but effective function
GetParamVal(const TaggedParm : string;
IgnoreCase : boolean = true) : string;
and Delphi's FindCmdLineSwitch() one can very easily determine
the values of command lines such as
MyExe dsn=oracle1 /auto pass=pass123
MyExe /auto pass=pass123 dsn=oracle1
The order of the parameters and switches are now irrelevant.
eg.
DataBase1.AliasName := GetParamVal('dsn');
if GetParamVal('pass') 'manager' then ....
if FindCmdLineSwitch('auto',['-','/'],true) then ....
Answer:
function GetParamVal(const TaggedParm : string;
IgnoreCase : boolean = true) : string;
var Retvar : string;
i,Len : integer;
Comp1,Comp2 : string;
begin
RetVar := '';
Comp1 := TaggedParm + '=';
if IgnoreCase then Comp1 := UpperCase(Comp1);
Len := length(Comp1);
for i := 1 to ParamCount do begin
Comp2 := copy(ParamStr(i),1,Len);
if IgnoreCase then Comp2 := UpperCase(Comp2);
if (Comp1 = Comp2) then begin
RetVar := copy(ParamStr(i),Len + 1,length(ParamStr(i)));
break;
end;
end;
Result := RetVar;
end;