FMSLogo Code

Note that Bug #611 has been fixed.

Note that Bug #93 was fixed in FMSLogo 8.0.0.

Fix a typo in a comment

Refactoring: Extract validate_argument and use it in FIRST, BUTFIRST, LAST, BUTLAST.
This is an alternate form of validating an argument that doesn't modify the args list.

For 25 years, I had assumed that modifying the list was useful, like maybe it sped
things up the next time, but the argument is list recreated each time a primitive
is called, so changing it does nothing. I speculate that the reason the argument
list is modified is a cheap form of memory management for any new/converted arguments.

The code base will be easier to undersatnd if doesn't modify the argument list for
non-obvious reasons. This code base will also be easier to understand if it relies
on the return value from functions instead of calling functions that sometimes modify
their arguments.

Create separate procedures for a smoke test and bad input tests for BUTLAST.
This is consistent with how tests for similar procedures are structured.

Add separate functions for a smoke test and a bad input test of LAST.
This follows the structure of the tests for similar functions (FIRST, BUTFIRST, etc)

Test that -1 is a bad input for most fields of the SETLABELFONT font vector.

Split SETLABELFONTTEST into procedures which run different tests.

Fix a build break (add a missing semicolon)

Fix Bug #106; SETLABELFONT no longer modifies the input list when given bad input.

The problem was that SETLABELFONT extracted fields from the input list as individual
arguments, which sets the new value back into the list. The fix is to extract
all fields from the list and, if any of them are wrong, throw a "doesn't like" error
for the *entire list*, not individual fields.

The parsing/validation of each argument is handled by a new helper class CListArgumentParser.
This separates the logic for validating each field from the declaration of how each
input should be validated.

This change was made on GNU/Linux, where neither LABELFONT or SETLABELFONT is implemented.
It might need further adjustment.