As the discussions of chapter one indicated, this book is concerned in equal measure with the representation and manipulation of data on the one hand, and the technique of structuring programs on the other. Chapter two began the process of fleshing out the former. This chapter focuses on realizing three of the four program structure abstractions mentioned in chapter one.
General:
The concept of a flow of data or data stream is introduced.
Realized in the Modula-2 notation:
boolean variables
General:
redirection of standard data streams from within a program
Realized in the Modula-2 notation:
boolean expressions
General:
fine tuning loops, writing efficient code, replacing loops with closed forms where possible; style and prettyprinting; further discussion of preventing errors
Realized in the Modula-2 notation:
the IF .. THEN .. ELSIF .. ELSE construction for selection; the WHILE, and REPEAT forms of repetition; qualified import; prettyprinting, the use of FROM alone for qualified import