The tt(ERROR) function takes one argument: text to display to the standard
error stream. The current input file and line number are also displayed. After
displaying the text, the tt(yodl) program aborts with an exit status of 1.

The text passed to the function is expanded first. See the example.

The tt(ERROR) function is an example of a function that evaluates its argument
itself.

This command can be used, e.g., in a macro package when an incorrect macro is
expanded. In my macro package (see chapter ref(MACROPACKAGE)) the tt(ERROR)
function is used when the sectioning command tt(chapter()) is used in an
tt(article) document (in the package, tt(chapter)'s are only available in
tt(book)s or tt(report)s).

An analogous builtin function is tt(WARNING), which also prints a message but 
does not exit (see section ref(WARNING)).

    Example:
    In the following call, tt(COUNTERVALUE(NTRIES)) is replaced by its actual
value: 
        verb(
    ERROR(Stopping after COUNTERVALUE(NTRIES) attempts)
        )
    
