The text read off it
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Thus, the verb ADD will cause two or more items of data to be added together, the verb DISPLAY will cause specified information to be printed or otherwise displayed, and the verb STOP will cause the machine to halt. Verbs which act at object time are known as program verbs.
Operators
Not all words that cause action are verbs. For instance, the reader will learn later in this chapter how to order that a given action be carried out only if a certain condition is met. Consider the sentence IF A = B THEN MOVE A TO OUTPUT. This sentence contains only one verb, the word MOVE, yet it implies two separate operations. The MOVE operation, of course, is one of them; the other is a test to determine if the condition A = B has been met. However, the programmer does not have to write a verb directing the program to test for this condition, for the word IF serves the purpose. The Commercial Translator language contains several words and symbols (such as the arithmetic symbols) which are not verbs but which cause operations. They are called operators.
It is necessary to distinguish between verbs and operators, since they are used in different ways. Commercial Translator verbs may be easily recognized by the fact that all of them are words which serve also as verbs in the English language.
For a general indication of how verbs are used, the reader may refer to any of the examples used in Chapter 1. The specific rules governing each verb will be found in Chapter 3.
Names
Most of the words in a typical Commercial Translator program will be nouns. A noun, in the strictest sense, is a name, and the programmer will find it very useful to accept that definition and all of its implications. He will write procedures for handling data, but he will refer to the procedures and the data by name. He will rarely work with actual data, and he will never write actual machine instructions.
This is an important concept. As will be seen in Chapter 4, an electronic system has no way of recognizing data and procedures simply by looking at them. They can be identified only by their location within storage, and in the Commercial Translator system these storage locations are referred to by name. For this reason, Commercial Translator nouns will be spoken of hereafter as names.
Kinds of Names
Most of the names the programmer will use will fall into one of three general categories: data-names, procedure-names, and condition-names.
Data-Names
Data-names are names given to the data used in a program. As the programmer will see, data-names are assigned to kinds of data, not (except in the case of constants) to specific values. Thus, such a name as INTEREST.RATE would not refer to a specific interest rate, but to a class of data known as interest rates. Technically (although this need not concern the programmer), it would name an area in storage in which any of several specific interest rates might be placed for some purpose, such as computation.
Data-names may be assigned to single classes of data or to groups of data items. For example, the name PAYROLL.RECORD would probably refer to a group of individual items having such names as EMPLOYEE.NAME, EMPLOYEE.NUMBER, HOURLY.RATE, and so on. It is important to recognize that, in general, the name refers not to any specific value, but only to the kind of data.