Operating Experience with FORTRAN
A. E. Glennie · The Computer Journal · 1962
The formal parameters, which are each enclosed in quotation marks in the KDF9 text, are replaced automatically by sequences of instructions for getting access to the required quantities.The system allows calls by name and by value.In the example, VI and V2 correspond to the local variable s of the Report version.In this version the sum is accumulated double length and then rounded.The reason for providing so fully for machine-code procedures is to simplify the introduction of features which it would otherwise be inconvenient or impossible to express within ALGOL.For example, one might References need a set of procedures for evaluating some frequentlyused functions, and the running speed of the ALGOL versions, even when translated by an optimizing compiler, might not be sufficiently close to that of the corresponding machine-code versions.Input and output, and magnetictape procedures must either themselves be in machine code or make use of machine-code procedures.Something like the scheme we have proposed is necessary if one wishes to get beyond the stage of "read one number, punch one number."As was mentioned earlier, machine-code procedures and ALGOL procedures can be included in the library.It follows that the user of library procedures for input and output need know nothing about the KDF9 User Code.A matrix scheme proposed for use with our ALGOL system (Denison, 1962) makes use of a number of procedures which have already been expressed in ALGOL.It is probable that they will be rewritten in User Code for the sake of speed.