Bug parsing brackets within brackets

[SMUsamaShah]

Constant ::= [+-\{\}\[\]]

This fails with syntax error. Tried many combinations of \ to escape the characters, none is working correctly.

Grammar doesn't specify (or may be I haven't looked properly) but is there a special way to escape these characters?

[mingodad]

You need to use hexadecimal like:

[  -> #x5B
]  -> #x5D
{  -> #x7B
}  -> #x7D
...

[SMUsamaShah]

Thanks