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CALICO Journal, Volume 3 Number 2 41 PILOT, SNOBOL, and LOGO AS

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CALICO Journal, Volume 3 Number 2 41 PILOT, SNOBOL, and LOGO AS PILOT, SNOBOL, AND LOGO AS COMPUTING TOOLS FOR FOREIGN-LANGUAGE INSTRUCTION Ruth H. Sanders ABSTRACT Three programming languages widely available for microcomputers deserve attention from the foreign- language academic community because of their ease of use and their particular facility in manipulating language. PILOT, SNOBOL, and Logo are described and evaluated as tools for foreign-language CAI, and a small sample program in each language is given. A bibliography is included. KEYWORDS: PILOT, SNOBOL, Logo, description, evaluation, pattern-matching, programming languages, courseware development. Most programming languages would fail any reasonable test for user friendliness. BASIC, up to now the standard microcomputing language for computer non-professionals, can be daunting to those untrained in algorithmic thinking and manipulation of formal symbols. Higher-level languages like Pascal, C or Ada seem even less suited to computing novices. There are, however, programming languages that are relatively easy for beginners to learn and to use with some proficiency. Three of these, PILOT, SNOBOL, and Logo, are especially well suited to language manipulation. The foreign language professional who wants to write computer tutorials but does not want to invest a great deal of time learning to program should investigate these. In fact, even those who program in other languages may find that these three offer some advantages for certain kinds of programming tasks. This article describes these three languages but does not review any particular implementation of any of them. All are available for a wide range of microcomputers, at varying costs; implementations on various machines or operating systems are not identical, and some implementations offer advantages over others. A bibliography (at end) lists sources for further information about the three languages. Only briefly addressed in the evaluations is the question of foreign- character availability. Usually additional software (and possibly additional hardware) is necessary for the use of non- English characters on the screen from within a programming language.1 PILOT PILOT (acronym for Programmed Inquiry, Learning Or Teaching) is a special-purpose language for educational programming, one of several and the one currently most easily and inexpensively available for microcomputers. PILOT is a true programming language rather than an authoring system or template and thus offers the possibility of creative educational programming even to the computer novice. Authoring languages like PILOT—computing languages that are especially designed for tutorial programming—address the need of educational professionals who want to program but are not expert or experienced at programming. Since, until recently, most educational computing was done on mainframe computers, most authoring languages were not available for microcomputers. Now, however, PILOT is available for virtually all microcomputers with CP/M operating systems, and for a wide variety of others as well, including the Apple and the IBM-PC. PILOT was created by Dr. John A. Starkweather at the University of California in the 1960s. Unlike the other well-known authoring languages and authoring systems, PILOT is in the public domain (i.e., the language itself is not copyrighted, though particular implementations of it my be). Many implementations are available at prices ranging from free to several hundred dollars. Usually at least 32K of memory is required. While some versions (for example, Common PILOT and its offspring Apple SuperPILOT) include graphics and sound, other versions do not. (The user should be warned that additional hardware may be necessary in order for graphics software to function.) As with so much computer software, price is no indication of quality. PILOT is not very good at numerical computing, organizing data, or solving general problems. However, it is very convenient for programming CAI tutorials, from the standard drill-and-practice exercises to games. As with any CALICO Journal, Volume 3 Number 2 41 computer language, within the limits inherent in the design of the language, the imagination of the programmer plays the greatest role in determining the application. PILOT EVALUATION +FOCUS PILOT's problem domain is interactive, conversational computer-assisted instruction (CAI). Since CAI programming is usually done by computer novices, it is useful to have a programming language without the usual difficulties to non-experts. PILOT has been effective in this application. PILOT's focus is narrow: it is a good applications tool for many varieties of CAI, but it is not convenient for solving problems that exist independent of computer-human interaction. +DEFINITION PILOT's syntax is simple. This simplicity also limits its flexibility. This problem can be overcome to some extent by imaginative programming, which however may not be available to its targeted users, novice programmers. PILOT's code consists of a one- or two-letter command followed optionally by a condition, then some text. Here are some typical commands in PILOT: T means Type this on the screen; A means Accept an answer; M means Match answer to this; C means Compute—assign a numerical value to a variable; Y and N mean Yes and No and are used as conditioners for commands, telling the program what to do if the learner's answer does or does not match the pattern of the most recent M statement. Standard dialect: The core commands, that is, the eight one-letter commands in the language, are shared by most implementations. Two-letter commands and numeric functions sometimes differ among dialects. The closest thing to a standard dialect is Common PILOT. Tutorial programs can be written using only the core instructions, and these should be relatively easy to transfer to machines other than those they were written for. Experienced PILOT programmers, however, will nearly always want to use more than the one-letter commands to make their tutorials more flexible and sophisticated. Programs written in PILOT are in principle widely portable. As with other programming languages including BASIC, portable should be taken with a grain of salt. What portable usually implies is that, although programs will have to be rewritten when being transferred to a different system, they may not have to be entirely rewritten, and the new code will most likely be easily understood by any programmer experienced in that language. As with other language documentation, manufacturer or distributor documentation varies in quality, sometimes making the language seem harder than it is in practice. For example, I find Starkweather's documentation of Nevada PILOT relatively clear even for novices, but I find Apple SuperPILOT's instruction booklet overwritten and oddly baffling. Unfortunately for the novice user, there do not appear to be any commercially available how-to booklets to supplement the official documentation. +IMPLEMENTATION PILOT is generally implemented as an interpreter, rather than a compiler. When a language is interpreted rather than compiled, an extra step between writing a program and running it is omitted. To the programmer, the program appears to run immediately, rather than having to be compiled—an extra step at the computer terminal. The ease of use of an interpreted language offers considerable attraction, especially to a novice computer user. However, this also means that a program written in the interpreted language will probably be subject to license agreement; that is, it can't be given away or sold without the agreement of the copyright owner of the interpretation. With a compiled language, programs written in the language are usually (not always) separate from the language, and can thus be given away or sold by the program author without permission from the language vendor. BASIC, like PILOT, is interpreted, but because most microcomputers come equipped with BASIC, the potential audience for the program already has permission to use the language. On the other hand, most vendors of PILOT understand that its main use is for CAI programs in schools and colleges, and will often give professors or teachers permission to let unlimited numbers of students use a PILOT program so long as only one person at a time can use the language disk itself. There are at least two versions of PILOT in the public domain. They are free of charge to anyone who gets the magazines where they appeared and types the program into the appropriate computer (one is for any Intel 8080 processor, and one specifically for TRS-80).2 PILOT is widely available in many implementations, often more than one for each machine. Some versions are quite complete; others limited. A few implementations, for instance, do not allow any numeric functions, which seriously limits tutorials' ability to provide help to students on the basis of how many errors they make. +INTERFACE Versions differ in the amount of access they offer to the underlying hardware or software of the host machine. To the writer of foreign-language CAI, this may mean difficulty in taking advantage of foreign-language character sets even if they are available on the machine itself. Apple's versions of PILOT, for example, provide a facility for creating characters that do not appear on its American keyboard; the PILOT versions available for CP/M typically do not. Depending upon the target language of the lesson and the tolerance of student and teacher, lack of foreign characters may or may not be experienced as a serious disadvantage. CALICO
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