This discussion about whether or not ANT should have more advanced features such as templates is amusing because the obvious answer is that if your software system is so large that you need such advanced features, then your build system should include both a dependency-generation program as well as a dependency-reading program.
ANT and MAKE are dependency-reading programs. They are meant to read dependency scripts and fire the actions. They are not meant as human-written scripting languages for large software systems. Dependency-generation programs are those that write out the dependency scripts: they generate the ANT or MAKE build scripts so that humans don't have to. As software systems grow in size, the folly of trying to use the dependency scripts to define your whole software build system becomes more and more apparent. No matter how many advanced features you add to your dependency-reading program, you will always be able to build large software systems easier using a dependency-generation program in combination with the dependency-reading program. In fact, the only reason to add advanced features to ANT or MAKE is to allow them to be used (however awkwardly) for medium-sized software projects. For large software projects it is clear that using the two programs in combination is infinitely easier than trying to build the whole system with only a dependency-reading program. Indeed, MAKE has become exorbitantly bloated with "advanced" features over the years, but still it is completely inadequate for large software systems unless it is used in combination with a dependency-generation program. Mathematically the reason why using the two programs together is easier is that the dependency-generation program requires only Constant time effort (it is not dependent on the size of the software system being built), whereas dependency scripts always require at least some O(n) effort (n is the number of lines of source code being built). Furthermore, using a dependency-generation program allows you to minimize the O(n) effort by putting the "smarts" of the build system in the dependency-generation program, thus allowing the O(n) scripts to be reduced to their smallest possible size. Indeed, when used with a good dependency-generation program, the O(n) effort is so small that it is easily handled by the source code developers themselves. Theoretically if a software system is "sufficiently uniform" than a feature as simple as templates could allow ANT or MAKE to be used without a dependency-generation program; but of course as software systems grow in size, their degree of uniformity inevitably lessens due to the increasing need for automation and other advanced build features, so there is always a point at which the use of a separate dependency-generation program is easier. Ultimately, software build systems should provide the most advanced build features to the end-user (the software developer) while reducing the O(n) build script maintainence effort to its minimal value. And this is precisely why using the two programs in combination is so effective: coding the advanced features of a build system in the Constant-time part (the dependency-generation program) will always require less effort than coding them in the O(n) part (the dependency scripts). What this means for the future direction of ANT is that we shouldn't repeat the mistakes of MAKE by continuing to pile on more and more features of dubious usefullness. Instead we should focus our efforts on providing an ANT file generator that is sufficiently general to be useful to the software community at large. The irony of using a dependency-generator program is that when you have one you only need very basic features in the dependency-reading program. ANT doesn't need any more features, it needs a companion ANT file generator program! --- Jerry Huth Sun Microsystems (650) 786-4658 [EMAIL PROTECTED] ------------------------------------------------------------------------- Jason Rosenberg wrote: > > > On 1/6/01 9:40 PM, "Jason Rosenberg" <[EMAIL PROTECTED]> wrote: > > > > > Ant is procedural, and that is what I want. It is close to being useful, > > > to date, but just needs to add a very small set of features to close the > > > case. Simply admitting that it is procedural would really clear the way. > > > Let's stop beating around the bush. > > > > Nope. Let's not. There are things that Ant needs. IMHO, turning into > > something procedural isn't one of them. I'd rather just write my > > buildscripts in JavaScript if that were the case. > > > > Well, I got into this debate because I wanted to have reusable templates > which are applied across a large set of like modules, etc. And, as we have > seen, Ant 1.2 is still not adequate in terms of templating, etc. So, this > leaves us with having to use JavaScript, via the script task, if we want > to have any sort of elegance with Ant. So, for now, not only are you > right in saying that if you want to do anything procedural, you should > use JavaScript, you also need to add that you really end up doing > everything in JavaScript anyway, even when you are using Ant. > > > I come down to the opinion that calling something data or code is pretty > > tough. After all, software is just data at some point. :) However there is a > > visceral line drawn about what Ant is good for, and at what point it's not. > > That line has been labeled with the somewhat, but sort of useful terms of > > "procedural vs. declarative". Neither term is totally appropriate. But we > > use them anyway :) > > > > Ant is a build management tool. It's purpose is to build software. This > means doing things like javac and javadoc and copy and ejbjar, etc. > These are all procedural tasks. If you want to be able to represent > a software build module declaratively, then you need to be able > to define it as a data object, with attributes which define how to > build it. In order to do this constructively, you simply have to have > templates or sub-routines, etc. > > > > Yes, I think the beauty of Ant is that it has the power to keep > > > things simple and human readable. I like the <execute-task> > > > idea mentioned by someone on another topic, or possibly a > > > simple case: > > > > > > <case property="caseProperty"> > > > <if value="1" execute="doMainCompile"/> > > > <if value="2" execute="doPartialBuild"/> > > > <default execute="showErrorAndFaile"/> > > > </case> > > > > But here you are saying you want a "if" target implementation that could > > take any set of attributes and do something. "<execute-target>" only does > > just that. It's a difference. And, imho, it's a big one. > > > > I don't understand what you said here.
