PLANC - PLANC Data Types

PLANC Data Types

As with all high level languages PLANC uses variables as can be seen in the previous sample, here are the allowed data types within PLANC:

• Simple types

  INTEGER, REAL, BOOLEAN, LABEL, VOID, ENUMERATION, POINTER

• Composite types

  ARRAY, RECORD, SET, ROUTINE

• User defined types: declared by TYPE T = .....;

An enumeration was declared thus:

ENUMERATION (Winter, Spring, Summer, Autumn) : Seasons := Summer

This defines an enumeration of the seasons and sets the default value to Summer.

LABEL is a little different from your normal data type, this is used to pre-define a label within code and is used in conjunction with a GO statement (very much like GOTO in BASIC).

Access modifiers can be applied to make them READ or WRITE only.

For string data several predefined datatypes are used, they are:

1. . BYTE Contains a single character
2. . BYTES Contains character strings
3. . BITS Contains BIT strings

Array pointers were 3-word constructs that included both the base address, the lower bound and the higher bound of the array; this made it possible to do reliable run-time checking of array boundaries, and made the kind of "pointer arithmetic" that makes C such an "interesting" language much less tempting to write.