Redefining the word language
Hello All, To respond to the previous discussion related to programming languages and natural languages, I decided to start a new discussion. My purpose here is to explain a kind of language theory that I developed quite many years ago. A classic book about the C programming language begins with a program that contains the statement printf(hello, world); It has been said, however, that the printf function that is used in the above statement does not belong to the language itself but it is a library function. To me, this raises questions: Why begin a book about a programming language by showing something that does not belong to the language? If the above printf function does not belong to the used programming language, into which language it belongs? To respond to questions like these in the context of computer programs, I have redefined the word language so that there does not exist pure programming languages or natural languages. Instead, each computer program or any other document has its own language that can be defined as a set of symbols. For example, the language used in the above statement, consists of the symbols printf ( hello , world ) ; Similarly, it would be possible to list all the symbols that are used in this message. That set of symbols would be the language used in this message. The language of the single statement above would then be a sub-language of the language of this message. With this kind of view to languages it is possible to try to figure out how complex some programs or other documents are. The language theory is explained in more detail in the paper http://www.naturalprogramming.com/to_read/estimating_understandability_etc.pdf I would like to emphasize that I discuss languages here from the human point of view (e.g. how a human understands a computer program.) How a compiler 'understands' a program is quite well defined. When a language is treated as a set of symbols, less emphasis is put to the syntax of the language. It can be assumed that it is part of the meaning of a symbol how it can be connected with other symbols. In the world of (spoken) languages the meanings of symbols change. For example, originally the word 'Google' was a noun (name), but later on it has been used as a verb. It is also important to note that a person can think that another person has misunderstood a symbol or a set of symbols of a language. I cannot know how you interpret the symbols that are used in this message. However, I can be sure that the symbols themselves will stay the same regardless of how they are understood. A person can have a weak or strong meaning for a symbol. For example, the meaning of the symbol 'printf' above can vary depending on how much the reader is familiar with C programming. I think this theory of languages is related to the quasi-linguisticness that was discussed in an earlier thread. - Kari -- The Open University is incorporated by Royal Charter (RC 000391), an exempt charity in England Wales and a charity registered in Scotland (SC 038302).
Re: Computers are systems not languages
On 24/02/2011, at 5:18 AM, alex wrote: Hi Andrew, Thanks for the illuminating response, On 22 February 2011 03:39, Andrew Walenstein walen...@ieee.org wrote: Even if you don't like these two arguments, surely most would admit that *one* of the primary purposes of good programming languages is human-human communication. In fact, this was an essential point of the title of Peter Naur's collection Computing: A Human Activity. In this narrow sense programming languages and natural languages are not incomparable. I hadn't read Peter Naur's work before, and am now very much enjoying what I can find. I've just got my hands on a copy of the collection you cite, and it includes the following: PROGRAMMING LANGUAGES ARE NOT LANGUAGES--WHY 'PROGRAMMING LANGUAGE' IS A MISLEADING DESIGNATION http://www.naur.com/comp/c8-4.html This seems very relevant to this discussion! Although Naur thinks computing is a human activity, Naur doesn't appear to think that programming languages are languages. This is the same Naur who wrote I cannot help expressing a feeling of awkwardness at the use of the word language in the context programming language. I definitely feel that if taken literally this habit of expression is misleading. As a first step to subdue our feeling of guilt at this misuse of the term, perhaps we can remind ourselves that logicians and mathematicians used the word for specialized notations long before we did, already in the 1930's, and perhaps even before. ... Several of the social aspects of mathematics and natural languages show a meaningful analogy with similar aspects of programming languages. It therefore makes sense to extrapolate the analogy to further such aspects. in a paper devoted to pursuing some of those analogies: Programming Languages, Natural Languages, and Mathematics, Peter Naur, CACM 18(12) December 1975. After a quick read his argument seems to be that grammar rules are not important to language, but that speech is the primary form of language, and that speech is ungrammatical. Language then is not a thing that can be specified, but rather something you do, by speaking. He asserts that dictionaries and the like are unimportant, and people demonstrably don't understand each other's utterances anyway, at least not very far. That is, that meaning is a personal matter. Someone who uses language to tell us something is by his actions *denying* that meaning is a personal matter, for if it were so, he might as well expect the same outcome from grunting and scratching his chest. -- The Open University is incorporated by Royal Charter (RC 000391), an exempt charity in England Wales and a charity registered in Scotland (SC 038302).
