FMSLogo Code

Add a missing line break

Refactoring: Change lbutlast to use CAppendableList.
This reduces code duplication.

Rework char_arg to take the argument instead of an argument list.
Also, rename it to validate_char_argument since it follows the new conventions of the validate* functions.

Refactoring: Change the signature of char_arg() to return a wchar_t instead of NODE*.
This is what all of the callers want, anyway.

This change makes it clear that char_arg() is responsible for freeing whatever it allocates.

Rework char_arg() so that it doesn't modify the input list.
This is part of a wider effort to simplify the code base by removing side effects.

Add additional tests for ASCII to prepare for refactoring of char_arg().

Fix the way the empty string is expressed in some RUNRECOVERABLEERRORTEST tests.
It's currently impossible to put an empty string into a list literal.
What looked like the empty string ended up being ignored.

This change replaces the list literal with a call to LIST, which can create a list that contains the empty string.

Refactoring: rename lbfs to lbutfirsts for consistency with how other logofuncs are named.
Most other primitives are implemented by functions that are named as "l" concatenated to the primitive's full name, not an abbreviation.

Fix an off-by-one error in the translation of a byte buffer to a Unicode string.
This wasn't consequential because make_buffer allocated an extra wchar_t for a NUL-terminator and initialized the buffer to zeros (with calloc) beforehand. Still, it's better for the code
to logically correct in addition to functionally correct.

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