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SQL::Statement::FunctiUser)Contributed Perl DocumenSQL::Statement::Function(3)

NAME
       SQL::Statement::Function	- abstract base	class for all function
       executing terms

SYNOPSIS
	 # this	class does not have a common constructor, because all derived classes
	 # have	their special requirements

DESCRIPTION
       SQL::Statement::Function	is an abstract base class providing the
       interface for all function executing terms.

INHERITANCE
	 SQL::Statement::Function
	 ISA SQL::Statement::Term

METHODS
   DESTROY
       Destroys	the term and undefines the weak	reference to the owner as well
       as the reference	to the parameter list.

NAME
       SQL::Statement::Function::UserFunc - implements executing a perl
       subroutine

SYNOPSIS
	 # 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, \@params );
	 # access the result of	that operation
	 $term->value( $eval );

DESCRIPTION
       SQL::Statement::Function::UserFunc implements a term which returns the
       result of the specified subroutine.

INHERITANCE
	 SQL::Statement::Function
	 ISA SQL::Statement::Term

METHODS
   new
       Instantiates a new "SQL::Statement::Function::UserFunc" instance.

   value
       Invokes the given subroutine with the values of the params and return
       it's result:

	   my @params =	map { $_->value($eval);	} @{ $self->{PARAMS} };
	   return $subpkg->$subname( $self->{OWNER}, @params );

NAME
       SQL::Statement::Function::NumericEval - implements numeric evaluation
       of a term

SYNOPSIS
	 # 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, \@params );
	 # access the result of	that operation
	 $term->value( $eval );

DESCRIPTION
       SQL::Statement::Function::NumericEval implements	the numeric evaluation
       of a term. All parameters are expected to be numeric.

INHERITANCE
	 SQL::Statement::Function::NumericEval
	 ISA SQL::Statement::Function
	   ISA SQL::Statement::Term

METHODS
   new
       Instantiates a new "SQL::Statement::Function::NumericEval" instance.
       Takes $owner, $expr and \@params	as arguments (in specified order).

   value
       Returns the result of the evaluated expression.

NAME
       SQL::Statement::Function::Trim -	implements the built-in	trim function
       support

SYNOPSIS
	 # 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, \@params );
	 # access the result of	that operation
	 $term->value( $eval );

DESCRIPTION
       SQL::Statement::Function::Trim implements string	trimming.

INHERITANCE
	 SQL::Statement::Function::Trim
	 ISA SQL::Statement::Function
	   ISA SQL::Statement::Term

METHODS
   new
       Instantiates a new "SQL::Statement::Function::Trim" instance.  Takes
       $owner, $spec, $char and	\@params as arguments (in specified order).

       Meaning of the parameters:

       $spec
	   Can be on of	'LEADING', 'TRAILING' 'BOTH'. Trims the	leading	chars,
	   trailing chars or at	both ends, respectively.

	   Defaults to 'BOTH'.

       $char
	   The character to trim - defaults to ' '

       \@params
	   Expected to be an array with	exact 1	element	(more are not
	   evaluated).

   value
       Returns the trimmed value of first parameter argument.

NAME
       SQL::Statement::Function::SubString - implements	the built-in
       sub-string function support

SYNOPSIS
	 # 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 \@params
	 my $term = SQL::Statement::SubString->new( $owner, $start, $length, \@params );
	 # access the result of	that operation
	 $term->value( $eval );

DESCRIPTION
       SQL::Statement::Function::SubString implements a	sub-string extraction
       term.

INHERITANCE
	 SQL::Statement::Function::SubString
	 ISA SQL::Statement::Function
	   ISA SQL::Statement::Term

METHODS
   new
       Instantiates a new "SQL::Statement::Function::SubString"	instance.
       Takes $owner, $start, $length and \@params as arguments (in specified
       order).

       Meaning of the parameters:

       $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.

       $length
	   Specifies the length	of the extracted sub-string. This is expected
	   to be a SQL::Statement::Term	instance.

	   If omitted, everything to the end of	the string is returned.

       \@params
	   Expected to be an array with	exact 1	element	(more are not
	   evaluated).

   value
       Returns the extracted sub-string	value from first parameter argument.

NAME
       SQL::Statement::Function::StrConcat - implements	the built-in string
       concatenation

SYNOPSIS
	 # create an substr function term with an SQL::Statement object	as owner
	 # and \@params	to concatenate
	 my $term = SQL::Statement::StrConcat->new( $owner, \@params );
	 # access the result of	that operation
	 $term->value( $eval );

DESCRIPTION
       SQL::Statement::Function::StrConcat implements a	string concatenation
       term.

INHERITANCE
	 SQL::Statement::Function::StrConcat
	 ISA SQL::Statement::Function
	   ISA SQL::Statement::Term

METHODS
   new
       Instantiates a new "SQL::Statement::Function::StrConcat"	instance.

   value
       Returns the concatenated	string composed	of the parameter values.

AUTHOR AND COPYRIGHT
       Copyright (c) 2009-2020 by Jens Rehsack:	rehsackATcpan.org

       All rights reserved.

       You may distribute this module under the	terms of either	the GNU
       General Public License or the Artistic License, as specified in the
       Perl README file.

perl v5.32.1			  2020-10-21	   SQL::Statement::Function(3)

NAME | SYNOPSIS | DESCRIPTION | INHERITANCE | METHODS | NAME | SYNOPSIS | DESCRIPTION | INHERITANCE | METHODS | NAME | SYNOPSIS | DESCRIPTION | INHERITANCE | METHODS | NAME | SYNOPSIS | DESCRIPTION | INHERITANCE | METHODS | NAME | SYNOPSIS | DESCRIPTION | INHERITANCE | METHODS | NAME | SYNOPSIS | DESCRIPTION | INHERITANCE | METHODS | AUTHOR AND COPYRIGHT

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