operator
file string-expression (is | isnt) writable
The file ... is writable test is used to determine if the system path named by the string expression
is writable by the OmniMark program. This is useful to avoid a program error when writing
out to a file. Using isnt instead of is will reverse the results.
This test will succeed if the named system path exists and is writable, or if the named system path does not exist, but can be created.
For example, the following program shows how file ... is writable is used to avoid attempting to write
to a file that cannot be be written to:
process local stream errors assert file "errors.txt" is writable open errors as file "errors.txt