10.4.3  lower-case identifiers

Mythryl uses lower-case identifiers to name constants, variables, functions and packages. Their syntax is:

    [a-z][a-z'_0-9]*

Note in particular that apostrophe is a legal constituent of such identifier names. As in mathematics, a trailing apostrophe is often used to mark a slight variant of a variable:

    foo                 # Some value.
    foo'                # Closely related value.

Some lower-case identifiers are reserved and not available for programmer use as vanilla identifiers:

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