Feedback on UTR#31 (draft 1): Full/Half-Width Characters.

I suggest that all compatibility character which are labelled <wide>, <narrow> and <small> and whose compatibility decompositions is already in class <Pattern_Syntax> be added in class <Pattern_Syntax> as well.

In practice, I am suggesting to add the following lines to section "4.1 Proposed Pattern Properties":

	FE50..FE52 ; Pattern_Syntax # SMALL COMMA..SMALL FULL STOP
	FE54..FE57 ; Pattern_Syntax # SMALL SEMICOLON..SMALL EXCLAMATION MARK
	FE59..FE66 ; Pattern_Syntax # SMALL LEFT PARENTHESIS..SMALL EQUALS SIGN
	FE68..FE6B ; Pattern_Syntax # SMALL REVERSE SOLIDUS..SMALL COMMERCIAL AT
	FF01..FF0F ; Pattern_Syntax # FULLWIDTH EXCLAMATION MARK..FULLWIDTH SOLIDUS
	FF1A..FF20 ; Pattern_Syntax # FULLWIDTH COLON..FULLWIDTH COMMERCIAL AT
	FF3B..FF40 ; Pattern_Syntax # FULLWIDTH LEFT SQUARE BRACKET..FULLWIDTH GRAVE ACCENT
	FF5B..FF5E ; Pattern_Syntax # FULLWIDTH LEFT CURLY BRACKET..FULLWIDTH TILDE
	FF5F..FF61 ; Pattern_Syntax # FULLWIDTH LEFT WHITE PARENTHESIS..HALFWIDTH IDEOGRAPHIC FULL STOP
	FF64       ; Pattern_Syntax # HALFWIDTH IDEOGRAPHIC COMMA
	FFE0..FFE2 ; Pattern_Syntax # FULLWIDTH CENT SIGN..FULLWIDTH NOT SIGN
	FFE4..FFE5 ; Pattern_Syntax # FULLWIDTH BROKEN BAR..FULLWIDTH YEN SIGN
	FFE8..FFEE ; Pattern_Syntax # HALFWIDTH FORMS LIGHT VERTICAL..HALFWIDTH WHITE CIRCLE

Rationale. These characters are almost identical, visually and semantically, to their "normal width" counterparts. Allowing such characters in identifiers means allowing identifiers which look identical to expressions of a totally different kind. E.g., an identifier such as "foo，bar" (where "，" is U+FF0C FULLWIDTH COMMA), would look identical to expression "foo, bar" (identifier "foo" + comma + space + identifier "bar").

Regards.
Marco Cimarosti (marco.cimarosti@europe.com)