Syntax Semantcs Design: Use of Unicode Ellipsis Character vs Dot Dot Dot

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Syntax Semantics Design: Use of Unicode Ellipsis Character vs Dot Dot Dot

Xah Lee, 2011-05-16

I decided, to use the unicode char HORIZONTAL ELLIPSIS “…” (U+2026) instead of the common 3 dots “...” for all my online writings. So, spent the past couple hours replacing all 3 dots to the ellipsis glyph, starting with my Emacs Tutorial directory (~300 files; 421 replacements.) (I have yet to do it site-wide, about ~5k files.)

Note: the replacement are done on a case-by-case basis with human eye-balling, and cannot be done blind programatically, because some occurrences of consecutive 3 dots are parts of computer code, error messages, or other uses, and must remain as 3 dots, e.g. in regex, 3 dots is a pattern for 3 chars. This task is done using emacs's command “dired-do-query-replace-regexp”. (See: Emacs: Interactively Find & Replace String Patterns on Multiple Files and Find & Replace with Emacs.)

Why Use Ellipsis Instead of Dot Dot Dot?

Why have i decided to use the ellipsis glyph instead of the much convenient 3 dots? Traditionally, it is done usually for esthetic reasons in printing. However, for me, the reason is mostly syntax & semantics design considerations in the context of computer science. I favored the ellipsis character because ellipsis carries with it a distinct meaning. That is, the char's sole purpose is to indicate omission (or other similar purposes). However, using 3 dots for the same purpose is in some sense a hack and creates certain complexity and ambiguity.

Here's one way to see it. Let's say a program is to parse the text. (such as web search engine bots) When the program comes to the ellipsis char, it knows right there that char's meaning. (assuming the char is not being abused, such as used in ASCII art) But when it comes to a period, it is not sure, it has to parse more, until you reach 3 consecutive dots. But even when you got 3 dots, the meaning is still not as precises when compared to the dedicated ellipsis char, because 3 consecutive dots could mean lots of things. (e.g. such as in regex, or some other lang uses 2 dots as a sequence generating operator, e.g. in perl: print 1..9;. In Mathematica, 2 or 3 dots is the syntax that represents a repeating pattern in its pattern matching functions.)

From another perspective, the period character “.” (unicode name FULL STOP, old name PERIOD) is used for multiple purposes. For example: decimal separator “3.1415”, section number separator 1.2.3, numbered items (1. this 2. that), domain name separator 〔〕, as multiplication sign, as vector dot product operator in math. The meaning of the ellipsis symbol in comparison is far less context dependent.

Here's Wikipedia articles on them: Ellipsis, Full stop.

Is All This Important?

No, not really, but it's the sort of thing designers think about, especially those into computer language syntaxes and mathematical notations, me.

I, for my website, am rather particular and idiosyncratic about just every aspect. The content, the style of writing, diction, design, layout, down to, the glyph choices in punctuation (but in general i'm antithetic to being choosy on fonts and other typographical matters. See: The Moronicities of TypographyThe TeX Pestilence.).

The Naming of Ellipsis

It might be interesting to note that the etymology of the word ellipsis shares with the math curve ellipse, both are from the Ancient Greek: ἔλλειψις, “omission” or “falling short”. See this page: Conic Sections, quote:

Appollonius was the first to base the theory of all three conics on sections of one circular cone, right or oblique. He is also the one to give the name ellipse, parabola, and hyperbola. A brief explanation of the naming can be found in Howard Eves, An Introduction to the History of Math. 6th ed. page 172. (also see J H Conway's newsgroup message at conicsEtynomogy.txt.)

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