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.\" ========================================================================
.\"
.IX Title "SQL::Statement::Function 3"
.TH SQL::Statement::Function 3 "2020-10-21" "perl v5.36.1" "User Contributed Perl Documentation"
.\" For nroff, turn off justification. Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
SQL::Statement::Function \- abstract base class for all function executing terms
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 2
\& # this class does not have a common constructor, because all derived classes
\& # have their special requirements
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
SQL::Statement::Function is an abstract base class providing the interface
for all function executing terms.
.SH "INHERITANCE"
.IX Header "INHERITANCE"
.Vb 2
\& SQL::Statement::Function
\& ISA SQL::Statement::Term
.Ve
.SH "METHODS"
.IX Header "METHODS"
.SS "\s-1DESTROY\s0"
.IX Subsection "DESTROY"
Destroys the term and undefines the weak reference to the owner as well
as the reference to the parameter list.
.SH "NAME"
SQL::Statement::Function::UserFunc \- implements executing a perl subroutine
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 6
\& # create an user function term with an SQL::Statement object as owner,
\& # specifying the function name, the subroutine name (full qualified)
\& # and the parameters to the subroutine
\& my $term = SQL::Statement::Function::UserFunc\->new( $owner, $name, $sub, \e@params );
\& # access the result of that operation
\& $term\->value( $eval );
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
SQL::Statement::Function::UserFunc implements a term which returns the result
of the specified subroutine.
.SH "INHERITANCE"
.IX Header "INHERITANCE"
.Vb 2
\& SQL::Statement::Function
\& ISA SQL::Statement::Term
.Ve
.SH "METHODS"
.IX Header "METHODS"
.SS "new"
.IX Subsection "new"
Instantiates a new \f(CW\*(C`SQL::Statement::Function::UserFunc\*(C'\fR instance.
.SS "value"
.IX Subsection "value"
Invokes the given subroutine with the values of the params and return it's
result:
.PP
.Vb 2
\& my @params = map { $_\->value($eval); } @{ $self\->{PARAMS} };
\& return $subpkg\->$subname( $self\->{OWNER}, @params );
.Ve
.SH "NAME"
SQL::Statement::Function::NumericEval \- implements numeric evaluation of a term
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 5
\& # create an user function term with an SQL::Statement object as owner,
\& # specifying the expression to evaluate and the parameters to the subroutine
\& my $term = SQL::Statement::NumericEval\->new( $owner, $expr, \e@params );
\& # access the result of that operation
\& $term\->value( $eval );
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
SQL::Statement::Function::NumericEval implements the numeric evaluation of a
term. All parameters are expected to be numeric.
.SH "INHERITANCE"
.IX Header "INHERITANCE"
.Vb 3
\& SQL::Statement::Function::NumericEval
\& ISA SQL::Statement::Function
\& ISA SQL::Statement::Term
.Ve
.SH "METHODS"
.IX Header "METHODS"
.SS "new"
.IX Subsection "new"
Instantiates a new \f(CW\*(C`SQL::Statement::Function::NumericEval\*(C'\fR instance.
Takes \fI\f(CI$owner\fI\fR, \fI\f(CI$expr\fI\fR and \fI\e@params\fR as arguments (in specified order).
.SS "value"
.IX Subsection "value"
Returns the result of the evaluated expression.
.SH "NAME"
SQL::Statement::Function::Trim \- implements the built\-in trim function support
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 5
\& # create an trim function term with an SQL::Statement object as owner,
\& # specifying the spec, char and the parameters to the subroutine
\& my $term = SQL::Statement::Trim\->new( $owner, $spec, $char, \e@params );
\& # access the result of that operation
\& $term\->value( $eval );
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
SQL::Statement::Function::Trim implements string trimming.
.SH "INHERITANCE"
.IX Header "INHERITANCE"
.Vb 3
\& SQL::Statement::Function::Trim
\& ISA SQL::Statement::Function
\& ISA SQL::Statement::Term
.Ve
.SH "METHODS"
.IX Header "METHODS"
.SS "new"
.IX Subsection "new"
Instantiates a new \f(CW\*(C`SQL::Statement::Function::Trim\*(C'\fR instance.
Takes \fI\f(CI$owner\fI\fR, \fI\f(CI$spec\fI\fR, \fI\f(CI$char\fI\fR and \fI\e@params\fR as arguments
(in specified order).
.PP
Meaning of the parameters:
.IP "\fI\f(CI$spec\fI\fR" 4
.IX Item "$spec"
Can be on of '\s-1LEADING\s0', '\s-1TRAILING\s0' '\s-1BOTH\s0'. Trims the leading chars, trailing
chars or at both ends, respectively.
.Sp
Defaults to '\s-1BOTH\s0'.
.IP "\fI\f(CI$char\fI\fR" 4
.IX Item "$char"
The character to trim \- defaults to \f(CW\*(Aq \*(Aq\fR
.IP "\fI\e@params\fR" 4
.IX Item "@params"
Expected to be an array with exact 1 element (more are not evaluated).
.SS "value"
.IX Subsection "value"
Returns the trimmed value of first parameter argument.
.SH "NAME"
SQL::Statement::Function::SubString \- implements the built\-in sub\-string function support
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 6
\& # create an substr function term with an SQL::Statement object as owner,
\& # specifying the start and length of the sub string to extract from the
\& # first element of \e@params
\& my $term = SQL::Statement::SubString\->new( $owner, $start, $length, \e@params );
\& # access the result of that operation
\& $term\->value( $eval );
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
SQL::Statement::Function::SubString implements a sub-string extraction term.
.SH "INHERITANCE"
.IX Header "INHERITANCE"
.Vb 3
\& SQL::Statement::Function::SubString
\& ISA SQL::Statement::Function
\& ISA SQL::Statement::Term
.Ve
.SH "METHODS"
.IX Header "METHODS"
.SS "new"
.IX Subsection "new"
Instantiates a new \f(CW\*(C`SQL::Statement::Function::SubString\*(C'\fR instance.
Takes \fI\f(CI$owner\fI\fR, \fI\f(CI$start\fI\fR, \fI\f(CI$length\fI\fR and \fI\e@params\fR as arguments
(in specified order).
.PP
Meaning of the parameters:
.IP "\fI\f(CI$start\fI\fR" 4
.IX Item "$start"
Specifies the start position to extract the sub-string. This is expected
to be a SQL::Statement::Term instance. The first character in a string
has the position 1.
.IP "\fI\f(CI$length\fI\fR" 4
.IX Item "$length"
Specifies the length of the extracted sub-string. This is expected
to be a SQL::Statement::Term instance.
.Sp
If omitted, everything to the end of the string is returned.
.IP "\fI\e@params\fR" 4
.IX Item "@params"
Expected to be an array with exact 1 element (more are not evaluated).
.SS "value"
.IX Subsection "value"
Returns the extracted sub-string value from first parameter argument.
.SH "NAME"
SQL::Statement::Function::StrConcat \- implements the built\-in string concatenation
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 5
\& # create an substr function term with an SQL::Statement object as owner
\& # and \e@params to concatenate
\& my $term = SQL::Statement::StrConcat\->new( $owner, \e@params );
\& # access the result of that operation
\& $term\->value( $eval );
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
SQL::Statement::Function::StrConcat implements a string concatenation term.
.SH "INHERITANCE"
.IX Header "INHERITANCE"
.Vb 3
\& SQL::Statement::Function::StrConcat
\& ISA SQL::Statement::Function
\& ISA SQL::Statement::Term
.Ve
.SH "METHODS"
.IX Header "METHODS"
.SS "new"
.IX Subsection "new"
Instantiates a new \f(CW\*(C`SQL::Statement::Function::StrConcat\*(C'\fR instance.
.SS "value"
.IX Subsection "value"
Returns the concatenated string composed of the parameter values.
.SH "AUTHOR AND COPYRIGHT"
.IX Header "AUTHOR AND COPYRIGHT"
Copyright (c) 2009\-2020 by Jens Rehsack: rehsackATcpan.org
.PP
All rights reserved.
.PP
You may distribute this module under the terms of either the \s-1GNU\s0
General Public License or the Artistic License, as specified in
the Perl \s-1README\s0 file.