The arguments for “exec” are esoteric and complicated. They will be described in detail in this section. When a better method for specifying these arguments is developed, they will be replaced. The arguments of “exec” describe how to substitute the directory name and file name, being passed to “exec”, into the dynamic arguments specified in the attached job. There are four symbols that represent this information. They are “$D$”, “$F$”, “::”, “$I$”, and they represent:
| $D$ The name of the input directory |
| $F$ The name of the input image file |
| :: A file separator, a back slash (Windows), or a forward slash (MacOS) |
| $I$ An iteration parameter, defined within the “exec” module |
Wherever “exec” finds the “$D$” occurring, it substitutes the specified directory name. Similarly, it substitutes the file name into “$F$”. For example, if one wants to have the directory and file names entered as the input to a Readlmage module, one can put “$input$” in the argument of Readlmage, and “$D$::$F$” into the “input” argument in “exec”. Shown below is an argument window for “exec”.
The argument “$input$” was entered in Readlmage, and the argument “$title$” was entered in Show. Those two names show up as the labels in the arguments for “exec”. For the “input”, the expression “$D$::$F$” means use the specified file name on the specified directory. For the “title”, using only the file name is specified.
Let's look at a specific example, on Windows, where the directory and file are given by:
| Directory name C:\lmage Files\Smith 093r |
| File name Smith 093r+MB9401R 016 F.tif |
With these as the input directory and file names, the “exec” arguments translate to:
| input | $D$::$F$ | C:\Image Files\Smith_093r\Smith_093r+MB9401_016_F.tif |
| title | $F$ | Smith_093r+MB9401R_016_F.tif |
The “exec” module will take the command from the attached job, find the dynamic arguments “$input$”, and “$title$”, and substitute the actual file path names into the command, and execute the new command. The module will wait until the job is completed, then pass on a “completed” message to the next module and wait for the next directory and file name message.
The iteration parameter, “$I$” is used to iterate a single iteration number over a range. The job is executed once for each iteration, each time with a new iteration number. To function, though, the iteration parameter requires a specific argument modification. These modifications are explained in the next section.