There are several techniques you can use to access data from a file, including the split command, as Jo suggested. Possibly an even simpler approach is to use the value() function. This function will evaluate any text as a SenseTalk expression, so if your file is structured using standard SenseTalk expressions it will be very easy to read and process.
For example, one way to do this would be to make each line of your file a SenseTalk list, like this:
("one","two"("item31","item32","item33"),"item 4","item 5, including a comma")
Then you can process the file like this:
repeat with each line of file "myData"
set dataList to value(it)
-- work with the information in dataList
To make this work, each line of the file will need to be a list, including the opening and closing parentheses, and it is a good idea to quote your text values as shown on the second line of the example data file above. If your data file is generated from an outside source and doesn’t have parentheses, you can supply them in your script like this:
set dataList to value( "(" & it & ")" )
This technique can also be used to load information that was previously stored to a file by another script. When creating such a file from a script, it is recommended that you use the standardFormat() function to write the data out, which will properly quote all of the values as needed.
If you continue to have trouble with this, please post a simple script example so we can offer specific suggestions.