Issue 17821: String concrete syntax is missing (uml25-ftf)
Source: Nomos Software (Dr. Edward Willink, ed(at)willink.me.uk)
Nature: Revision
Severity: Minor
Summary: Specifying a Concrete Syntax requires just that. It must provide a solution to expressing all characters in a predictable fashion. So given the constraint of "..." encapsulation, how are internal " represented? How are Unicode and newlines expressed? Suggest reusing the OCL 2.3 clarification of backslashes. The concrete syntax comprises a sequence of zero or more characters or escape sequences surrounded by single quote characters. The [B] form with adjacent strings allows a long string literal to be split into fragments or to be written across multiple lines.[A] StringLiteralExpCS ::= #x27 StringChar* #x27
[B] StringLiteralExpCS[1] ::= StringLiteralExpCS[2] WhiteSpaceChar* #x27 StringChar* #x27

where

StringChar ::= Char | EscapeSequence

WhiteSpaceChar ::= #x09 | #x0a | #x0c | #x0d | #x20

Char ::= [#x20-#x26] | [#x28-#x5B] | [#x5D-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]

EscapeSequence ::= '\' 'b' -- #x08: backspace BS
| '\' 't' -- #x09: horizontal tab HT
| '\' 'n' -- #x0a: linefeed LF
| '\' 'f' -- #x0c: form feed FF
| '\' 'r' -- #x0d: carriage return CR
| '\' '"' -- #x22: double quote "
| '\' ''' -- #x27: single quote '
| '\' '\' -- #x5c: backslash \
| '\' 'x' Hex Hex -- #x00 to #xFF
| '\' 'u' Hex Hex Hex Hex -- #x0000 to #xFFFF

Hex ::= [0-9] | [A-F] | [a-f]

A minor change could share the syntax definition and define the body as above prohibiting un-escaped usage of the character used as the surrounding quotes.

Resolution: 
Revised Text: 
Actions taken:
September 26, 2012: received issue
Discussion: 

End of Annotations:=====
s is issue # 17821

Problem: 8.007

Severity: Medium
Type: Structural 
Location: 8.2.4 Notation 2nd bullet p 76
Title: String concrete syntax is missing 
Description
 
Specifying a Concrete Syntax requires just that. It must provide a solution to expressing all characters in a predictable fashion. So given the constraint of "..." encapsulation, how are internal " represented? How are Unicode and newlines expressed? Suggest reusing the OCL 2.3 clarification of backslashes. The concrete syntax comprises a sequence of zero or more characters or escape sequences surrounded by single quote characters. The [B] form with adjacent strings allows a long string literal to be split into fragments or to be written across multiple lines.[A] StringLiteralExpCS ::= #x27 StringChar* #x27
[B] StringLiteralExpCS[1] ::= StringLiteralExpCS[2] WhiteSpaceChar* #x27 StringChar* #x27
 
where
 
StringChar ::= Char | EscapeSequence
 
WhiteSpaceChar ::= #x09 | #x0a | #x0c | #x0d | #x20
 
Char ::= [#x20-#x26] | [#x28-#x5B] | [#x5D-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]
 
EscapeSequence ::= '\' 'b' -- #x08: backspace BS
| '\' 't' -- #x09: horizontal tab HT
| '\' 'n' -- #x0a: linefeed LF
| '\' 'f' -- #x0c: form feed FF
| '\' 'r' -- #x0d: carriage return CR
| '\' '"' -- #x22: double quote "
| '\' ''' -- #x27: single quote '
| '\' '\' -- #x5c: backslash \
| '\' 'x' Hex Hex -- #x00 to #xFF
| '\' 'u' Hex Hex Hex Hex -- #x0000 to #xFFFF
 
Hex ::= [0-9] | [A-F] | [a-f]
 
A minor change could share the syntax definition and define the body as above prohibiting un-escaped usage of the character used as the surrounding quotes.
 
Source: Edward Willink