Is it acceptable to use a single hyphen as a dash (as the BBC does)?
Venezuela - a major oil producer - has been heavily affected by the fall in oil prices on international markets.
Like many institutions in the UK, the BBC has published its entire style guide online. The style guide is massive and detailed and is the result of hundreds of combined years of writing and editorial experience. Like other major style guides, we can assume that each rule is well-considered, and since all style guides change, we know that rules are often reconsidered.
Before looking at the BBC's rules, let us talk briefly talk about American English and its use of hyphens and dashes. The post pointed to by @tchrist is an incredibly concise and clear explanation of American usage of hyphens and dashes. (Although, it does not explicitly mention not to use spaces.) I have not read an American style guide that dissented on this topic.
The BBC is British, however, so it is possible that they view dashes the way they view colours. In looking through the style guide, I am quite surprised that I could not find any discussion of en-dash or em-dash. In fact, the guide seems quite comfortable interchanging the word hyphen with dash.
All of the relevant pages I could find:
Conclusion: if you are writing for the BBC, your example is required; if you are writing using American style guidelines, then the example you provided is absolutely wrong; and if you are writing using British style guidelines, then I would look for more authorities on the topic.
Generally speaking there's little difference between British and American use of dashes, at least as compared to hyphens. The use of a hyphen character (or technically hyphen-minus) made sense in legacy (pre-unicode) systems as the dashes weren't always available and were encoded at different code points in different systems. That hasn't been a good excuse for some time though.
Is possible they're spaced En-dashes but I assume you've checked. http://en.m.wikipedia.org/wiki/Dash says that spaced En-dashes and unspaced Em-dashes may both be used as parenthetical dashes.
Using multiple hyphens as a substitute for dashes is useful for avoiding ambiguity but shouldn't be expected in web or print output. It's how LaTeX for example inputs dashes and so you'll see it in text formats -- including here.
No, it is not typographically acceptable to use a hyphen for a dash, but you have mischaracterized the issue. Those are spaced en dashes, which is just fine. If you have only a typewriter, things get confused, but in properly typeset books, there is a world of difference.
You have to judge these things based on what they are doing, not on accidents of fontage.
They are being represented by U+002D HYPHEN-MINUS, but that is an accident of software and ambiguous data entry. They are functioning as dashes, so that is what they are. That’s like when you write a
−3. You are still using what is functionally a minus sign, even if you have typed U+002D and nothing changed it to the preferred U+2122 MINUS SIGN code point.
Technically speaking, Unicode has 27 code points with the “Dash” character property. How they look will vary according to the font selected and the display software. Each of them has its own set of properties that help software determine what to do with line-breaks and such. These are the 27 Unicode
Dash=Yes code points:
Code Glyph Name General Category ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ U+002D - HYPHEN-MINUS Dash_Punctuation U+058A ֊ ARMENIAN HYPHEN Dash_Punctuation U+05BE ־ HEBREW PUNCTUATION MAQAF Dash_Punctuation U+1400 ᐀ CANADIAN SYLLABICS HYPHEN Dash_Punctuation U+1806 ᠆ MONGOLIAN TODO SOFT HYPHEN Dash_Punctuation U+2010 ‐ HYPHEN Dash_Punctuation U+2011 ‑ NON-BREAKING HYPHEN Dash_Punctuation U+2012 ‒ FIGURE DASH Dash_Punctuation U+2013 – EN DASH Dash_Punctuation U+2014 — EM DASH Dash_Punctuation U+2015 ― HORIZONTAL BAR Dash_Punctuation U+2053 ⁓ SWUNG DASH Other_Punctuation U+207B ⁻ SUPERSCRIPT MINUS Math_Symbol U+208B ₋ SUBSCRIPT MINUS Math_Symbol U+2212 − MINUS SIGN Math_Symbol U+2E17 ⸗ DOUBLE OBLIQUE HYPHEN Dash_Punctuation U+2E1A ⸚ HYPHEN WITH DIAERESIS Dash_Punctuation U+2E3A ⸺ TWO-EM DASH Dash_Punctuation U+2E3B ⸻ THREE-EM DASH Dash_Punctuation U+301C 〜 WAVE DASH Dash_Punctuation U+3030 〰 WAVY DASH Dash_Punctuation U+30A0 ゠ KATAKANA-HIRAGANA DOUBLE HYPHEN Dash_Punctuation U+FE31 ︱ PRESENTATION FORM FOR VERTICAL EM DASH Dash_Punctuation U+FE32 ︲ PRESENTATION FORM FOR VERTICAL EN DASH Dash_Punctuation U+FE58 ﹘ SMALL EM DASH Dash_Punctuation U+FE63 ﹣ SMALL HYPHEN-MINUS Dash_Punctuation U+FF0D － FULLWIDTH HYPHEN-MINUS Dash_Punctuation
So even when U+002D HYPHEN-MINUS is being used, it is still dash punctuation. It’s just the worst one to to use from the point of view of accurate typography, a vestige of the old teletypes and manual typewriters that no longer applies.
If the BBC websites aren’t converting the code point into U+2013 EN DASH per UK publishing norms, that’s just laziness, the sort of thing you have in people’s cell phone text messages, not professional typesetting.
Are you asking whether it is acceptable in America? I believe most reputable style guides (for example, Elements of Style (Strunk&White) and Chicago Manual of Style)) will tell you it is not.
The example in the question calls for em-dashes (without spaces).