Chapter 3 - THE YEARS OF ALGOL AND PL1

Abstract

This chapter provides an overview of ALGOL and PL1 in the 60s. ALGOL created six types of statements—namely, (1) the indicative statement; (2) the conditional statement; (3) the alternative statement; (4) the repetitive statement; (5) the iterative statement; and (6) the declarative statement. ALGOL contains a Goto statement that allows the transfer of control to any other statement by using its label as the target of the Goto. ALGOL, as a new language, had everything that could have avoided the war of structured programming. It contained all the required artefacts for clean program writing. However, ALGOL did not make it because there was a lack of sponsoring. ALGOL was the achievement of scientists and for quite a while, the product remained confined to those circles. No practical compiler was readily available. When an ALGOL compiler became available in the mid 60s, it had to cope with a lot of antagonism. ALGOL PL1 is an ALGOL-like language. PL1 took over many of the structural ideas of ALGOL, in particular the block structure, the nesting of constructs, and the scope rules and recursion. PL1 attempted to merge the features and semantics of both FORTRAN and COBOL with the structures of ALGOL. It was the first language that undertook honestly the task of offering resource management and program flexibility. Just like ALGOL, PL1 allows the writing of function subroutines. PL1 aimed at providing comfort and coherence to the programmer.