The standard environment

The standard environment corresponds to what is usually known as the ``run-time library'' in other language environments such as C or Pascal.

New variable environments may be introduced in various ways (see chapter ), but a T system is obliged to supply one standard environment in which system variables are bound to system procedures and constants, as defined by this manual. Program execution typically occurs in an environment inferior to this standard environment (see section ), so that these objects are easily accessible as values of lexically apparent variables. For example, in this standard environment, the variable CONS has a certain procedure as its value.

For the most part, the values of system variables are procedures, and therefore the only behavior of interest is what they do when called. (See the discussion of calls, above.) In other cases, values are objects such as numbers or symbols.

A representation of the standard environment is available as the value of STANDARD-ENV (page ).