# Functions

RainerScript supports a currently quite limited set of functions:

- getenv(str) - like the OS call, returns the value of the environment variable, if it exists. Returns an empty string if it does not exist.
- strlen(str) - returns the length of the provided string
- tolower(str) - converts the provided string into lowercase
- cstr(expr) - converts expr to a string value
- cnum(expr) - converts expr to a number (integer)
- wrap(str, wrapper_str) - returns the str wrapped with wrapper_str. Eg. wrap(“foo bar”, “##”) would produce “##foo bar##”
- wrap(str, wrapper_str, escaper_str) - returns the str wrapped with wrapper_str. But additionally, any instances of wrapper_str appearing in str would be replaced by the escaper_str. Eg. wrap(“foo’bar”, “’”, “_”) would produce “‘foo_bar’”
- replace(str, substr_to_replace, replace_with) - returns new string with all instances of substr_to_replace replaced by replace_with. Eg. replace(“foo bar baz”, ” b”, ”, B”) would return “foo, Bar, Baz”.
- re_match(expr, re) - returns 1, if expr matches re, 0 otherwise. Uses POSIX ERE.
- re_extract(expr, re, match, submatch, no-found) - extracts data from a string (property) via a regular expression match. POSIX ERE regular expressions are used. The variable “match” contains the number of the match to use. This permits to pick up more than the first expression match. Submatch is the submatch to match (max 50 supported). The “no-found” parameter specifies which string is to be returned in case when the regular expression is not found. Note that match and submatch start with zero. It currently is not possible to extract more than one submatch with a single call.
- field(str, delim, matchnbr) - returns a field-based substring. str is the string to search, delim is the delimiter and matchnbr is the match to search for (the first match starts at 1). This works similar as the field based property-replacer option. Versions prior to 7.3.7 only support a single character as delimiter character. Starting with version 7.3.7, a full string can be used as delimiter. If a single character is being used as delimiter, delim is the numerical ascii value of the field delimiter character (so that non-printable characters can by specified). If a string is used as delmiter, a multi-character string (e.g. “#011”) is to be specified. Samples: `set $!usr!field = field($msg, 32, 3);` – the third field, delimited by space `set $!usr!field = field($msg, "#011", 3);` – the third field, delmited by “#011” Note that when a single character is specified as string [field($msg, ”,”, 3)] a string-based extraction is done, which is more performance intense than the equivalent single-character [field($msg, 44 ,3)] extraction.
- prifilt(constant) - mimics a traditional PRI-based filter (like “*.*” or “mail.info”). The traditional filter string must be given as a constant string. Dynamic string evaluation is not permitted (for performance reasons).

The following example can be used to build a dynamic filter based on some environment variable:

    if $msg contains getenv('TRIGGERVAR') then /path/to/errfile