SIMSCRIPT II.5 Programming Language

Programming Language Concepts
Figure 2-8. A Complex Tree
The ability to use the dim.f function makes it easy to allow each node to have several branches,
rather than only two. Such a tree might look like figure 2-8.
2.24 Pre-Processing Program Text
In the interests of readability, SIMSCRIPT II.5 provides two program text substitution facilities.
The first allows a defined sequence of words to be substituted for a single word. The statement:
word to mean sequence of words
means that each occurrence of word in the program text is replaced, before interpretation, by a sequence
of characters. The word to be replaced may be any name, single character, or sequence of
characters not containing a blank. However, only clearly identifiable occurrences are replaced.
Embedded occurrences in other strings are not extracted for replacement. The string to be substituted
may be any sequence of characters or words, delimited by the end of a statement line. It may
contain embedded blanks. Comment text is not affected. This feature provides, for instance, the
ability to represent the constants that frequently appear in programs as meaningful names. Including
such definitions, for example, as:
define .IDLE.STATUS to mean 0
define .BUSY.STATUS to mean 1
define .DOWNSTREAM to mean 2
allows statements to be written as:
if STATUS.CODE = .BUSY.STATUS
or DIRECTION = .DOWNSTREAM
let STATUS = .IDLE.STATUS
while being interpreted as:
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