Perl代写|CSE-112 Program 4 Perl and Rapid Development


1. Overview

Scripting is a style of programming whereby small programs are developed rapidly.

This is also sometimes called rapid prototyping. Perl is a language which supports
this particular programming paradigm very well because it is a very powerful and
interpreted language. There is no need to do the usual compile-run cycle, since the
program is compiled every time it is run.

The make(1) utility determines automatically which pieces of a large program need
to be recompiled, and issue the commands to recompile them. This project will also
enhance your knowledge of make and Makefiles, as presented in prerequisite courses.

Every programmer should have a detailed knowledge of make.

2. An implementation of a subset of make

In this assignment, you will use Perl to write a replacement for a subset of make.

pmake — perl implementation of a subset of make

pmake [-d] [target]

The pmake utility executes a list of shell commands associated with each target,
typically to create or update files of the same name. The Makefile contains
entries that describe how to bring a target up to date with respect to those on
which it depends, which are called prerequisites.

The following options are supported. All options must precede all operands,
and all options are scanned by Getopt::Std::getopts (perldoc).
-d Displays debugging information. Output is readable only to the imple
mentor. Other debugging flags may also be added, but none are produc
tion flags.

The following operand is recognized.

An attempt is made to build each target in sequence in the order they are
given on the command line. If no target is specified, the first target in
the Makefile is built. This is usually, but not necessarily, the target all.

Reads the file called Makefile in the current directory. If the file does not exist,
pmake exits with an error message.