basic.statements

differences between statements and functions in Pick/BASIC, a working definition of variable, constant, labels, blanks, and program formatting.

If the syntax requires that the instruction be followed by a set of parentheses (optionally containing an argument or arguments), then it is a function. For example, the following are functions: 'abs(num.expression)', 'rnd(num.expression)' and 'iconv(string.expression, conv.expression)'.

Any instruction that does not have to be followed by a set of parentheses is most often a statement. For example: 'print x', 'input y', 'execute sentence'.

There is at least one peculiar exception to the above rule. One variant of the 'locate' statement is considered a statement, even though its syntax looks like it should be a function.

Another feature of statements is that they tend to 'stand alone'. For instance: 'execute sentence' or 'print array<10,1>'.

Functions, by contrast, do not stand alone. They are either used as part of an expression within a statement: 'raise = rnd(20)', or output immediately: 'crt int(amount)', 'print abs(balance)'.

A Pick/BASIC program is composed of statements made up of Pick/BASIC commands, variables, constants, expressions, and functions.

Pick/BASIC statements may contain arithmetic, relational, and logical expressions. These expressions are formed by combining specific operators with variables, constants, or Pick/BASIC intrinsic functions.

The value of a variable may change dynamically throughout the execution of a program. A constant, as its name implies, has the same value throughout the execution of a program.

An intrinsic function performs a pre-defined operation on the supplied parameter(s).

Normally, within a Pick/BASIC program, each physical line contains only one statement. This is done for ease of reading and tracking of logic.

More than one statement may be placed on a program line by separating each statement with a ';' (semicolon). Statements which end with 'then' or 'else' on a line create a block or multi-line structure. See the 'if' statement for details on 'then...else' statements.

Labels may be placed at the beginning of any Pick/BASIC statement. A statement label may be numeric or alphanumeric. See 'statement labels'.

Blank spaces appearing in the program line which are not part of a literal are ignored. Blank spaces and blank lines may be used freely within the program for purposes of appearance. (AP only -- R83 does not support blank source lines).