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   slapd-meta    ( 5 )

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Substitution Pattern Syntax:

Everything starting with `%' requires substitution;

the only obvious exception is `%%', which is left as is;

the basic substitution is `%d', where `d' is a digit; 0 means the whole string, while 1-9 is a submatch;

a `%' followed by a `{' invokes an advanced substitution. The pattern is:

`%' `{' [ <op> ] <name> `(' <substitution> `)' `}'

where <name> must be a legal name for the map, i.e.

<name> ::= [a-z][a-z0-9]* (case insensitive) <op> ::= `>' `|' `&' `&&' `*' `**' `$'

and <substitution> must be a legal substitution pattern, with no limits on the nesting level.

The operators are:

> sub context invocation; <name> must be a legal, already defined rewrite context name

| external command invocation; <name> must refer to a legal, already defined command name (NOT IMPL.)

& variable assignment; <name> defines a variable in the running operation structure which can be dereferenced later; operator & assigns a variable in the rewrite context scope; operator && assigns a variable that scopes the entire session, e.g. its value can be dereferenced later by other rewrite contexts

* variable dereferencing; <name> must refer to a variable that is defined and assigned for the running operation; operator * dereferences a variable scoping the rewrite context; operator ** dereferences a variable scoping the whole session, e.g. the value is passed across rewrite contexts

$ parameter dereferencing; <name> must refer to an existing parameter; the idea is to make some run-time parameters set by the system available to the rewrite engine, as the client host name, the bind DN if any, constant parameters initialized at config time, and so on; no parameter is currently set by either back-ldap or back-meta, but constant parameters can be defined in the configuration file by using the rewriteParam directive.

Substitution escaping has been delegated to the `%' symbol, which is used instead of `\' in string substitution patterns because `\' is already escaped by slapd's low level parsing routines; as a consequence, regex escaping requires two `\' symbols, e.g. `.*\.foo\.bar' must be written as `.*\\.foo\\.bar'.