.TH Concat
.PP
String concatenation
.SH Signature
.PP
.RS
.nf
concat(expr: AttrName|(Tuple->Numeric)) -> Aggregator
.fi
.RE
.SH Examples
.PP
.RS
.nf
concat(:name)
.fi
.RE
.PP
.RS
.nf
concat(:name, between: ', ')
.fi
.RE
.PP
.RS
.nf
concat(between: ', '){|t| t.name }
.fi
.RE
.PP
.RS
.nf
concat(->(t){ t.name.upcase }, between: ', ')
.fi
.RE
.SH Description
.PP
Concatenates string representations of input values.
.SH Implementation notes
.PP
This aggregate function can be applied to any data type, not only String
attributes. Ruby's \fB\fCto_s\fR will be used on values prior to concatenation.
.PP
The options are:
.RS
.IP \(bu 2
\fB\fCbefore\fR starts the resulting string (defaults to '')
.IP \(bu 2
\fB\fCafter\fR ends the resulting string (defaults to '')
.IP \(bu 2
\fB\fCbetween\fR is used between each value
.RE
.PP
As of current Alf version, the order in which the values are concatenated
is not guaranteed. So far, this function is thus non\-deterministic.