An alternative implementation of the Seq language which allows for warnings to be implicitly collected and stored in a list as your program executes.
As background see seq; here we only describe the differences between Seqw and Seq.
The difference is quite straightforward:
What is a warnings structure? When we use Seqw, we generally accumulate warnings into a list, so our actions just cons new warnings into this list when desired. But Seqw itself imposes no particular constraints on what a warnings structure is, and generally the way in which a warning is updated is determined by the actions of the program rather than by Seqw itself.
For examples of using SEQW, see the file