| ★ APPLICATIONS ★ PROGRAMMATION ★ HISOFT PASCAL80 ★ |
PASCAL 80 (c) HISOFT (Amstrad Action) | PASCAL 80 (Popular Computing Weekly) | PASCAL 80 : PCW PASCAL UPGRADED (Popular Computing Weekly) |
Hisoft's Pascal 80 has long been the standard package to recommend. It's solid, dependable and very short on gimmickry. It also costs £15 more than Oxford Pascal. For your £40 you get the standard Hisoft editor ED80.COM and a disk-resident compiler HP80.COM. You also get a fair few other files, but we can take a look at these later on. As usual, the first thing you'll be doing is writing your source code. You could use your favourite CP/M word processor/text editor for this, but ED80 will meet most people's needs handsomely. ED80's a full screen editor, and it uses almost the full set of WordStar control key combinations. This does strike me as a little strange - after all, if you know WordStar the chances are you've already got a copy of it, and won't need ED80. That said. ED80 only takes up 12K of disk and so is a lot more convenient on single-drive systems. In use ED80 is straightforward and, for a CP/M editor, quite fast. It doesn't behave exactly like WordStar, but that's not going to bother too many people. It can be configured for the larger 8256/8512 screen without too much difficulty, and it's size makes it a natural for the M: drive. As for HP80, it's just a good practical compiler. You call it up from disk in the usual way, so that typing HP80 PROGRAM will compile the file PROGRAM.PAS into PROGRAM.COM. It's pretty fast, and quite fussy. A missed semi-colon, for example, will produce an avalanche of errors on the next line. Pascal 80 would be the grand old man of Amstrad PASCALs if it wasn't for the way Hisoft keep adding to it. Since it was first launched it's gained not only random access filing but also a fascinating library of GSX graphics routines. Both of these come as PASCAL source code and are thoroughly documented. You can use them as procedures within your own programs, or read through them to study the techniques used - the latter being well worth the effort. This is all starting to add to the price of the system as far as beginners are concerned, but it does mean that the manual can give more experienced users the information they need. That's very important, and not just for hardened PASCAL fanatics. If you buy a package you're going to learn with, you don't want one you're going to outgrow too soon; nor do you want one that restricts you. It may not be aimed at beginners, but I'd still recommend Pascal 80 to anyone starting out. Beginners need the best and, for the price. I'd say that's Pascal 80. to disk as, say, PROGRAM.PAS, you'll then want to compile it. To do this you have to run the compiler. If the compiler was called, say. COMPILE.COM then you type something like COMPILE PROGRAM at the A > prompt. Assuming you haven't made any mistakes the compiler then produces a new file called PROGRAM.COM. This is the compiled version of your program, and behaves just like any other .COM file. That is, you can run it simply by typing PROGRAM at the A> prompt. The chances are that things won't go anywhere near so smoothly at first. PASCAL is very fussy, particularly about punctuation. If you make a mistake, it'll probably be spotted during compilation. The compiler will report the kind of mistake you've made, but it's not always very precise. Often you'll get several different error messages all set off by one mistake, there's also a tendency for the messages to crop up some way after the actual error, which only adds to the general confusion. P-CODE Some implementations of PASCAL don't work in quite the way that's described above. Instead of converting your commands into Z80 machine code, they translate it into a special language called P-code. Then an interpreter translates this P-code once the program is running. There are theoretical advantages to this. In particular, the same program is usually much smaller in P-code than it would have been in machine code. There are also several drawbacks to P-code compilation. A major problem is that P-code programs need the interpreter to be present when they run. If you want to turn a P-code program into a stand-alone program - something that can run without an interpreter - you'll need to put it through an extra processing stage. Turning a P-code program into a stand-alone .COM file usually makes it a great deal bigger. It could easily end up being larger than the file a normal compiler would have produced. JENSEN & WIRTH PASCAL is a highly standardised language - much more so than BASIC. A program written for one version of PASCAL should, in theory, need very little modification to compile on another. For the purposes of standardisation. PASCAL implementors refer to a specification drawn up by Jensen and Wirth back in 1975. PASCAL packages usually boast about how accurately they conform to the appropriate standard, but it doesn't actually mean that much these days. For what it's worth, neither of these packages could compile the other's demonstration files without considerable modification. ?
AMSTRAD ACTION n°12 |
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