[GENERAL] Using the dollar sign as a prefix for named parameter of prepared statement.

Hi all,

I'm working on finishing beta release of my C++ API for PostgreSQL. The library

have simple SQL parser (preprocessor) to support the queries like that:

  SELECT :"column", $tag$constant string$tag$

    FROM :tables

    WHERE name LIKE :'name' AND

          sex = $1 AND

          age > $age

  where:

    :"column" is a variable which will be quoted as identifier (like in psql),

    :tables is a variable which will be not be quoted at all (like in psql),

    :'name' is a variable which will be quoted as literal (like in psql),

    $1 is a positional parameter,

    $age is a named parameter

Is there are any contraindications/caveats/gotchas on using the dollar sign as a prefix for the named parameters?

According to https://www.postgresql.org/docs/10/static/sql-syntax-lexical.html

a) "SQL identifiers and key words must begin with a letter ..."

b) "The tag, if any, of a dollar-quoted string follows the same rules as an unquoted identifier ... "

c) "A dollar sign ($) followed by digits is used to represent a positional parameter in the body of a function definition or a prepared statement. In other contexts the dollar sign can be part of an identifier or a dollar-quoted string constant."

I don't see any problems with such a choise. Am I missing something?

Thanks!