Function concat( s1, s2, s3 )

Description:
Concatenates three strings. In most cases the same effect can be achieved by writing s1+s2+s3, but blank values can sometimes appear as the string "null" if you do it like that.
Parameters:
s1 (String)
first string
s2 (String)
second string
s3 (String)
third string
Return Value (String):
s1 followed by s2 followed by s3
Example:
concat("a", "b", "c") = "abc"
Signature:
java.lang.String concat(java.lang.String, java.lang.String, java.lang.String)