[swift-evolution] Strings in Swift 4

[Hooman Mehr]

> On Feb 7, 2017, at 12:19 PM, Ted F.A. van Gaalen via swift-evolution <swift-evolution at swift.org> wrote:
> 
> I now assume that:
>       1. -= a “plain” Unicode character (codepoint?)  can result in one glyph.=-

What do you mean by “plain”? Characters in some Unicode scripts are by no means “plain”. They can affect (and be affected by) the characters around them, they can cause glyphs around them to rearrange or combine (like ligatures) or their visual representation (glyph) may float in the same space as an adjacent glyph (and seem to be part of the “host” glyph), etc. So, the general relationship of a character and its corresponding glyph (if there is one) is complex and depends on context and surroundings characters.

>       2. -= a  grapheme cluster always results in just a single glyph, true? =- 

False

>       3. The only thing that I can see on screen or print are glyphs (“carvings”,visual elements that stand on their own )

The visible effect might not be a visual shape. It may be for example, the way the surrounding shapes change or re-arrange.

>      4.  In this context, a glyph is a humanly recognisable visual form of a character,

Not in a straightforward one to one fashion, not even in Latin / Roman script.

>      5. On this level (the glyph, what I can see as a user) it is not relevant and also not detectable
>          with how many Unicode scalars (codepoints ?), grapheme, or even on what kind
>          of encoding the glyph was based upon.

False

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