Semicolon

1. When a semicolon marks the left boundary of a constituent (e.g., the beginning of a clause or a phrase), the right boundary is marked by punctuation of equal or greater strength.
2. When two or more semicolons are used within a single construction, all constituents are at the same level, unlike commas, which can separate, for example, subordinate clauses from main clauses.

Semicolons are followed by a lower case letter, unless that letter would ordinarily be capitalized mid-sentence (e.g., the word "I", acronyms/initialisms, or proper nouns). In older English printed texts, colons and semicolons are offset from the preceding word by a non-breaking space, a convention still current in present-day continental French texts. Ideally, the space is less wide than the inter-word spaces. Some guides recommend separation by a hair space.[10] Modern style guides recommend no space before them and one space after. They also typically recommend placing semicolons outside ending quotation marks, although this was not always the case. For example, the first edition of The Chicago Manual of Style (1906) recommended placing the semicolon inside ending quotation marks.[11]

Applications of the semicolon in English include:

• Between items in a series or listing containing internal punctuation, especially parenthetic commas, where the semicolons function as serial commas. The semicolon divides the items on the list to more discrete parts, without which the remaining jumble of commas could cause confusion for the reader. This is sometimes called the "super comma" function of the semicolon:
  • The people present were Jamie, a man from New Zealand; John, the milkman's son; and George, a gaunt kind of man with no friends.
  • Several fast food restaurants can be found within the following cities: London, England; Paris, France; Dublin, Ireland; and Madrid, Spain.
  • Here are three examples of familiar sequences: one, two, and three; a, b, and c; first, second, and third.
  • (Fig. 8; see also plates in Harley 1941, 1950; Schwab 1947).

• There does not have to be an unreasonable amount of commas, however, for the usage of semicolons to be justified:
  ...either of the following punishments:

1. Death;

2. Imprisonment;

3. Fine;

4. Removal from office; or,

5. Disqualification to hold and enjoy any office of honor, trust, or profit in this State.[12]

• Between closely related independent clauses not conjoined with a coordinating conjunction, when the two clauses are balanced, opposed or contradictory:[13]
  • My wife would like tea; I would prefer coffee.
  • I went to the basketball court; I was told it was closed for cleaning.
  • I told Kate she's running for the hills; I wonder if she knew I was joking.

  Either clause may include commas; this is especially common when parallel wording is omitted from the second:

• Ted has two dogs; Sam, one.

• In rare instances, when a comma replaces a period (full stop) in a quotation, or when a quotation otherwise links two independent sentences:
  • "I have no use for this," he said; "you are welcome to it."
  • "Is this your book?" she asked; "I found it on the floor."[14]

In Arabic, the semicolon is called Fasila Manqoota (Arabic: فاصلة منقوطة‎) which means literally "a dotted comma", and is written inverted ؛. In Arabic, the semicolon has several uses:

• It can be used between two phrases, in which the first phrase causes the second.
  • Example: "He played a lot; so, his clothes became dirty". (Arabic: لَعِبَ كَثِيرًا؛ فَٱتَّسَخَتْ مَلَابِسُهُ.‎)
• It can be used between two phrases, where the second is a reason for the first.
  • Example: "Your sister did not get high marks; she didn't study". (Arabic: لم تحقق أختك درجات عالية؛ لأنها لم تدرس .‎)

In Greek and Church Slavonic, a semicolon indicates a question, similar to a Latin question mark.[15][6] To indicate a long pause or separate sections, each with commas (the semicolon's purpose in English), Greek uses, but extremely rarely, the Greek: άνω τελεία, romanized: áno teleía, lit. 'up dot', an Interpunct ·.

Church Slavonic example: гдѣ єсть рождeйсѧ царь їудeйскій; (Where is the one who is born king of the Jews? – Matthew 2:1)

Greek Example: Τι είναι μια διασύνδεση; (What is an interpunct?)

In French, a semicolon (point-virgule, literally "dot-comma") is a separation between two full sentences, used where either a colon or a comma would not be appropriate. The phrase following a semicolon has to be an independent clause, which is related to the previous one (but not explaining it, contrary to a sentence introduced by a colon).

The dash character is used in French writing too, but not as widely as the semicolon. Usage of these devices (semicolon and dash) varies from author to author.

In computer programming, the semicolon is often used to separate multiple statements (for example, in Perl, Pascal, and SQL; see Pascal: Semicolons as statement separators). In other languages, semicolons are called terminators[5] and are required after every statement (such as in PL/I,[22] Java, and the C family). Today semicolons as terminators has largely won out, but this was a divisive issue in programming languages from the 1960s into the 1980s.[23] An influential and frequently-cited study in this debate was Gannon & Horning (1975), which concluded strongly in favor of semicolon as a terminator: "The most important [result] was that having a semicolon as a statement terminator was better than having a semicolon as a statement separator."[24] The study has been criticized as flawed by proponents of semicolon as a separator,[25] due to participants being familiar with a semicolon-as-terminator language and unrealistically strict grammar. Nevertheless, the debate ended in favor of semicolon as terminator. Therefore, semicolon provides structure to the programming language.

Semicolons are optional in a number of languages, including BCPL, Python, Eiffel, and Go, meaning that they are part of the formal grammar for the language, but can be inferred in many or all contexts (e.g. by end of line that ends a statement (in Go)). As languages can be designed without them, semicolons are considered an unnecessary nuisance by some.[25]

The use of semicolons in control flow structures and blocks of code is varied  – semicolons are generally omitted after a closing brace, but included for a single statement branch of a control structure (the "then" clause), except in Pascal, where a semicolon terminates the entire if...then...else clause (to avoid dangling else) and thus is not allowed between a "then" and the corresponding "else", as this causes unnesting.

This use originates with ALGOL 60, and falls between the comma , – used as a list separator – and the period/full stop . – used to mark the end of the program. The semicolon, as a mark separating statements, corresponds to the ordinary English usage of separating independent clauses, and gives the entire program the gross syntax of a single ordinary sentence. Of these other characters, whereas commas have continued to be widely used in programming for lists (and rare other uses, such as the comma operator that separates expressions in C), they are rarely used otherwise, and the period as the end of the program has fallen out of use. The last major use of the comma, semicolon, and period hierarchy is in Erlang (1986), where commas separate expressions; semicolons separate clauses, both for control flow and for function clauses; and periods terminate statements, such as function definitions or module attributes, not the entire program. Drawbacks of having multiple different separators or terminators (compared to a single terminator and single grouping, as in semicolon-and-braces) include mental overhead in selecting punctuation, and overhead in rearranging code, as this requires not only moving lines around, but also updating the punctuation.[26]

In some cases the distinction between a separator and a terminator is strong, such as early versions of Pascal, where a final semicolon yields a syntax error. In other cases a final semicolon is treated either as optional syntax, or as being followed by a null statement, which is either ignored or treated as a NOP (no operation or null command); compare trailing commas in lists. In some cases a blank statement is allowed, allowing a sequence of semicolons or the use of a semicolon by itself as the body of a control flow structure. For example, a blank statement (a semicolon by itself) stands for a NOP in C/C++, which is useful in busy waiting synchronization loops.

APL uses semicolons to separate declarations of local variables, and to separate axes when indexing multi-dimensional arrays, for example matrix[2;3].

Other languages (for instance, some assembly languages and LISP dialects, CONFIG.SYS and INI files) use semicolons to mark the beginning of comments.

Example C code:

int main() {
  int x, y;
  x = 1; y = 2;
  printf("X + Y = %d", x + y);
  return 0;
}

Or in JavaScript:

var x = 1; var y = 2;
alert("X + Y = " + (x + y));

Conventionally, in many languages, each statement is written on a separate line, but this is not typically a requirement of the language. In the above examples, two statements are placed on the same line; this is legal, because the semicolon separates the two statements. Thus programming languages like Java, the C family, Javascript etc. use semicolons to obtain a proper structure in the respective languages.

The semicolon is often used to separate elements of a string of text. For example, multiple e-mail addresses in the "To" field in some e-mail clients have to be delimited by a semicolon.

In Microsoft Excel, the semicolon is used as a list separator, especially in cases where the decimal separator is a comma, such as 0,32; 3,14; 4,50, instead of 0.32, 3.14, 4.50.

In MATLAB and GNU Octave, the semicolon can be used as a row separator when defining a vector or matrix (whereas a comma separates the columns within a row of a vector or matrix) or to execute a command silently, without displaying the resulting output value in the console.

In HTML, a semicolon is used to terminate a character entity reference, either named or numeric. The declarations of a style attribute in Cascading Style Sheets (CSS) are separated and terminated with semicolons.[27]

The file system of RSX-11 and OpenVMS, Files-11, uses semicolons to indicate a file's version number.[28] The semicolon is permitted in long filenames in the Microsoft Windows file systems NTFS and VFAT, but not in its short names.[29]

In some delimiter-separated values file formats, the semicolon is used as the separator character, as an alternative to comma-separated values.