A few extremely random rules of English style: Drew McDermott 1 Avoid using "this" as a pronoun. It usually will have no clear antecedent, and will leave the reader confused. Here are some examples: "Try to eliminate excessive reliance on search from your programs. This tends to make them NP-complete." "Try to eliminate excessive reliance on search from your programs. This will make them polynomial." Often I see a long discussion of some topic, followed by a sentence beginning "This ...." It is impossible to tell what part of the discussion is being referred to. 2 Get the words "affect" and "effect" right. Each can be used as a noun and a verb, but by far the most common meanings are these: "Affect" used as a verb meaning "to have effects on" "Effect" used as a noun meaning "noticeable changes" "Effect" as a verb means "to cause, or bring about" (as in "effect a speedup of this algorithm"). "Affect" as a noun meaning "emotional reaction"; don't use this sense unless you are a clinical psychologist. I know of no clever mnemonic to remember which is which, so if you have trouble remembering, make a sign and paste it to your word processor. Also, "accommodate" is spelled with two c's and two m's. 3a Do not put a comma between the subject and predicate of a sentence: *"A person who reflects on the future of civilization, will have trouble sleeping at night." b Or between a verb or preposition and its object: *"He informed her politely, that she had been fired." *"The car skidded out of control and crashed through, the biggest plate-glass window in town." c Do not put a comma after a conjunction: *"You can say all you want to about Ronald Reagan but, he sure had a great tan." When the comma is needed, put it before the conjunction. If in doubt about it, put it in. Most sentences of written text consist of more than one clause, and almost all of those clauses require bracketing by commas. The only reason to omit them is to improve the literary rhythm, but who cares about that in technical writing? Compare He gambled, and he lost. He gambled and he lost. Each is equally appropriate; if clauses this short can stand commas, never hesistate to put one in. (Warning: professional editors, at least American ones, have been trained to be extremely anti-comma. It is unlikely nowadays that your prose will be edited by a pro, unless you write a book, but if it ever is you will be surprised by the number of commas they cross out. Don't worry; they usually know what they are doing.) d Put commas around a relative clause only if it is a parenthetical comment: "U.S. senators, who take bribes, will not like this legislation." With the commas, this sentence implies that all U.S. senators take bribes. Without them, it is *restrictive*, and picks out the subset who take bribes. (Native German writers, take note: In German both restrictive and nonrestrictive relative clauses take commas, so English written by Germans is often a bumpy ride.) With animate subjects, the relative pronoun can be "who" or "that" (or "whom", but see "Excessive pedantry, below). With inanimate subjects, the relative pronoun is "that" or "which." The former should be used for restrictive clauses, the latter for nonrestrictive. "All the buildings in town that were designed by Ms. Lin are covered with names and dates." "All the buildings in town, which were designed by Ms. Lin, are covered with names and dates." The latter sentence implies that every building in town was designed by Ms. Lin. e If a parenthetical insertion comes just where a comma belongs, put the comma after it: "Try replacing the memory board (the one behind the transformer), and if that doesn't work we'll send out a technician." I often see the comma before the parenthesis, or omitted entirely. 4 THE GENERAL THEORY OF COMMAS: Commas are used to separate items of the "same type": "Winken, Blinken, and Nod" (names) "I brought the hot dogs, potato salad, and ketchup." (noun phrases) "What will we do without buns, forks, or plates?" (noun phrases) "She was not only far from her intended route, but also headed in the wrong direction." (complement phrases) "I came, I saw, I conquered." (clauses) "We wanted to bring out the new product line immediately, but they insisted on a delay." (clauses) "Yesterday, December 7, 1941, a date which will live in infamy, the United States was suddenly and deliberately attacked...." (times) [FDR should have said "a date _that_ will live in infamy." As it happens, in the case of this passage the nonrestrictive reading is impossible anyway.] "We will expect your review by October 31, 2005." (times; years in dates always need a comma.) Note that if there are just two items, whether the comma is needed or not is governed by special rules (such as the restrictive-clause rule). (Also note that in British English it seems to be normal practice to omit the comma before the "and" that starts the last item in a list, as in "Winken, Blinken and Nod." This just looks wrong to an American; it seems to indicate that there are two items, the second of which is the pair Blinken and Nod. Compare "Winken, Blinken and Nod, and their mother, Flopsytail.") In many cases, a comma between two items is best thought of as the open bracket around the second item, the close bracket being supplied by another comma, the end of the sentence, or a semicolon: "Please reply by January 1, 2008, if possible." (brackets around year) "The fact that the budget deficit is high, while inflation continues to rage, should cause concern." (The second comma closes the "while" clause; its purpose is not to divide the subject -- "The fact ... to rage" -- from the predicate "should cause concern.") There is a natural tendency to think of a comma as the written equivalent of a slight pause in speech. However, no matter how dramatic the pause after "but" in the Reagan sentence above, no comma goes there. Instead, think of the subordinate clause ("but he sure has a great tan") as a substructure to be bracketed. The general theory explains why no comma should ever come between the subject and predicate: they are not of the same type. Clauses, subordinate or not, are of the same type, and hence are naturally separable, or bracketable, by commas. All you have to remember is that the conjunction goes with the clause it begins, and hence the comma comes before it. Although "I came, I saw, I conquered" is okay, bare commas may not be used to conjoin any clauses but extremely short, staccato ones. Longer ones need the comma to either be cushioned by a conjunction or replaced by a semicolon or period. If Caesar's report were to be lengthened, it might read "I invaded Gaul with 5 legions; I reconnoitred the situation thoroughly, then attacked and completely defeated the natives." 5 "However" is not a conjunction. It's a sort of "interjection," tossed in to contrast the sentence it occurs in with what has gone before. It normally is bracketed with commas. If in doubt about a case, try removing the word "however" and seeing if the result is still grammatical: *"This algorithm looked good on paper, however it completely bombed in practice." => *"This algorithm looked good on paper, it completely bombed in practice." Correct: "This algorithm looked good on paper; however, it completely bombed in practice." There is a less common use of the word in which "however" is a conjunction, meaning "no matter how": "They are bound to reject your advice, however you phrase it." I hope it is obvious that this sense is quite different from the more common one. "Otherwise" is just like "however." 6 Hyphenated phrases: Multiword phrases are hyphenated to make them easier to distinguish from their contexts. There are two main cases: a nouns modifying adjectives: problem-dependent, labor-intensive, ice-blue b phrases modifying nouns: -- simple noun phrases as modifiers: small-animal administration, arms-control agreement -- more exotic phrases as modifiers: hit-and-run accident, pig-in-a-poke deal. Note the difference: when a noun modifies an adjective, the hyphen goes between them. When a phrase modifies a noun, the phrase is hyphenated. Such phrases do not otherwise need hyphenation: "He wrote a problem-solving program" but "This thesis concerns problem solving." The reason for hyphenating simple noun phrases used as modifiers is to override the default that a string of words of the form "adjective noun noun" gets bracketed as (adjective (noun noun)), as in "small arms firm," which refers to a small company. To override the default, you must put in a hyphen, as in "small-arms firm." The "right associativity" convention applies to cases other than "adjective noun." Here's an example from a notice regarding parking in the driveway adjacent to an office building: "No parking signs will be installed in the near future." The writer meant to say "No-parking signs will be installed in the near future"; she ended up advising us not expect any parking signs, because the default grouping is (No (parking signs) will ...), not the intended (((No parking) signs) will ...). The reason for hyphenating more exotic noun-modifying phrases is that otherwise the reader will get lost in a string of disconnected words: "*We will profit from our cash and carry policy next year." Hyphens aren't necessary if the grouping they would indicate is already indicated some other way: "I reject the `ghost in the machine' hypothesis." (quotes indicate grouping) "I got My Fair Lady tickets." (caps indicate grouping) (The phrase "'right associativity' convention" as used above is another example.) If things get too recursive, rephrase: "Avoid noun-modifying-phrase-depth overload." => "Avoid constructing noun phrases that are so deep in modifying phrases that they are hard to decipher." 7 Avoid multiple negations. Consider the second sentence of this paragraph (from Franz's Allegro Common Lisp documentation; single quotes indicate typewriter font): "In releases prior to 6.1, Allegro CL ignored 'readtable-case' in all case modes except ':case-insensitive-upper' (the ANSI mode). Starting in release 6.1 of Allegro CL, 'readtable-case' is not ignored unless 'set-case-mode' is called with a _case-mode_ other than ':case-insensitive-upper' and _adjust-readtables-case_ specified 'nil'." With the negations highlighted, the central clause of the sentence is: "...'readtable-case' is NOT IGNORED UNLESS 'set-case-mode' is called with a _case-mode_ OTHER-THAN ':case-insensitive-upper' and -adjust-readtables-case_ specified NIL." -- a cascade of five negations! To get the meaning one can only count them and keep track of the parity. Here is how the paragraph ought to have been written: "In releases prior to 6.1, Allegro CL obeyed 'readtable-case' only in case mode :case-insensitive-upper (the ANSI mode). Starting in release 6.1 of Allegro CL, 'readtable-case' has an effect if and only if 'set-case-mode' is called with a _case-mode_ of ':case-insensitive-upper' OR with _adjust-readtables-case_ specified 't'." 8 There is such a thing as excessive pedantry. Some writers work hard to avoid "split infinitives," in which an adverb or some other modifier comes between the particle "to" and an infinitive verb. One famous example is the intro to Star Trek: "To boldly go where no one has gone before!" I used one above: "to either be cushioned by a conjunction or replaced by a semicolon." In fact, there is no rule of English grammar that forbids split infinitives. Although it is possible to create ridiculous-sounding infinitive by interposing some large and clumsy phrase, the same can be said for just about any construction. In a relative clause modifying an animate entity, if the "gap" in the clause should be occupied by an object, then technically one should use "whom" instead of "who." "The boy who gave her the gift blushed." "The boy whom she gave the gift blushed." (The first clause has a gap in the subject position: "who [ ] gave her the gift"; the second has a gap in the indirect-object position: "whom she gave [ ] the gift.") Many people find this rule very hard to follow, which indicates that it not a linguistically "real" rule. The New Yorker used to run examples of "whom" misused under the title "The Omnipotent Whom." Here is an example I found in Treharne's 2002 translation of Proust's "The Guermantes Way" (p. 384): "... like the briefly wide-open eyes and smile of a child in bed at night whom you thought was asleep." The relative clause is "you thought [ ] was asleep," and the gap clearly requires a pronoun in the nominative case (*"you thought him was asleep"). The moral of the story is not to worry about "whom"; no one will really mind if you use "who" everywhere. In colloquial English, the line between "nominative" and "accusative" case is not sharp. These are categories borrowed from Latin, devotees of which have often demanded that we say "It is I" when "It's me" is perfectly good English. For some odd reason, use of accusative case for subjects is allowed by some speakers only when the subject is a conjunction. Someone who would never say *"Me is going to the movies tonight" has no trouble saying "Me and her are going to the movies tonight." Although educated people avoid this usage, their attempts to train the unwashed to do likewise has succeeded only in convincing many people that a conjunction of pronouns must always be in the nominative case! That's why one hears the phrase "between you and I" so frequently; the obviously correct "between you and me" now sounds wrong to some people. It's a great illustration of the point that grammar is easy to learn and impossible to teach. [2005-12-29] Copyright 2005 Drew McDermott