106 Chapter 2 Evolution of the Major Programming Languages
container processes the JSTL parts of JSP documents in a way that is similar to
how the C/C++ preprocessor processes C and C++ programs. The preprocessor
commands are instructions for the preprocessor to specify how the output file is
to be constructed from the input file. Similarly, JSTL control action elements
are instructions for the JSP processor to specify how to build the XML output
file from the XML input file.
One common use of the if element is for the validation of form data
submitted by a browser user. Form data is accessible by the JSP processor and
can be tested with the if element to ensure that it is sensible data. If not, the
if element can insert an error message for the user in the output document.
For multiple selection control, JSTL has choose, when, and otherwise
elements. JSTL also includes a forEach element, which iterates over collec-
tions, which typically are form values from a client. The forEach element can
include begin, end, and step attributes to control its iterations.SUMMARY
We have investigated the development and the development environments of
a number of programming languages. This chapter gives the reader a good
perspective on current issues in language design. We have set the stage for an
in-depth discussion of the important features of contemporary languages.BIBLIOGRAPHIC NOTES
Perhaps the most important source of historical information about the devel-
opment of early programming languages is History of Programming Languages,
edited by Richard Wexelblat (1981). It contains the developmental background
and environment of 13 important programming languages, as told by the design-
ers themselves. A similar work resulted from a second “history” conference, pub-
lished as a special issue of ACM SIGPLAN Notices (ACM, 1993a). In this work,
the history and evolution of 13 more programming languages are discussed.
The paper “Early Development of Programming Languages” (Knuth and
Pardo, 1977), which is part of the Encyclopedia of Computer Science and Technology,
is an excellent 85-page work that details the development of languages up to
and including Fortran. The paper includes example programs to demonstrate
the features of many of those languages.
Another book of great interest is Programming Languages: History and Fun-
damentals, by Jean Sammet (1969). It is a 785-page work filled with details of
80 programming languages of the 1950s and 1960s. Sammet has also pub-
lished several updates to her book, such as Roster of Programming Languages for
1974–75 (1976).