Command line variable - how to check

[wells50]

When a compiled macro runs, sometimes it needs to check to see if a Command Line Parameter is present. Here is some code that illustrates how to check for a command line parameter:

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// COMPILE_OPTS|c:\programs\test.exe||CONSOLE=0|INCLUDES=1||RUNTIMES=1|BMPS=1
// Test for presence of a command line parameter
// To test with a parameter, at a Command Prompt enter: test /vtest=something
// To test without a parameter, just run test.exe
MidStr>%vtest%,1,1,vFirstCharacter
If>%vFirstCharacter%=%
  // If the command line parameter, vtest, was not present, %vtest% will not
  // yet be a variable and will be seen as a string with % as the first character.
  Let>vtest=
  // By setting the variable to nothing (empty), you avoid having the string %vtest%,
  // including the percent signs, appear when your program checks for the presence
  // of the command line parameter later on.
  MDL>There is no parameter value for vtest.  Here it is: %vtest%
Else
  MDL>Here the parameter, vtest:  %vtest%
Endif

Perhaps there is some much more elegant way to perform the check. If so, I welcome an alternative!

[Marcus Tettmar]

Hi,

Any reason why you wouldn't just use the Assigned function:

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Assigned>vTest,bGotvTest
If>bGotvTest=FALSE
  Let>vTest=some default value
Endif

[wells50]

Excellent! I hadn't known about the Assigned function. It is perfect for checking the existence of a variable assigned by the command line or otherwise. Thank you!

[mightycpa]

I didn't remember it either, even though I used it just the other day. First place I looked was in Help, under "Using Variables."

Suggest you add it in there too.

Here was my workaround:

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Let>IGNOREERRORS=1
ConCat>undeclared_var,
Length>undeclared_var,uvLen
If>uvLen=0
...

Assigned is MUCH better.