I. Alphabet and Words

The alphabet is standard ASCII, comprising digits, letters
(of the English alphabet), the underline (used in names and numbers),
the (single) quote, and others (which include the space)
to be referred to as graphics.

Numbers are denoted by digits, the underbar
(for negative signs and for infinity and minus infinity –
when used alone or in pairs), the period (used for decimal
points and necessarily preceded by one or more digits),
the letter e (as in 2.4e3 to signify 2400
in exponential form), and the letter j to separate
the real and imaginary parts of a complex number, as in 3e4j_0.56 .
Also see the discussion of

A numeric list or vector is denoted by a list of
numbers separated by spaces.
A list of ASCII characters is denoted by the list
enclosed in single quotes, a pair of adjacent single quotes
signifying the quote itself: 'can''t' is the five-character
contraction of the six-character English word 'cannot'.
The ace a: denotes the boxed
empty list <$0 .

Names (used for pronouns and other surrogates,
and assigned referents by the copula, as in prices=: 4.5 12)
begin with a letter and may continue with letters, underlines, and digits.
A name that ends with an underline or that contains two consecutive
underlines is a locative, as discussed in
Section II.I.

A primitive or primary may be denoted by
a single graphic (such as + for plus)
or by a graphic modified by one or more following
inflections (a period or colon), as in +. and +:
for or and nor.
A primary may also be an inflected name, as in e. and o.
for membership and pi times.