|
SQL::Statement::Function(3) User Contributed Perl Documentation SQL::Statement::Function(3) NAME SQL::Statement::Function - abstract base class for all function executing terms SYNOPSIS # this class doesn't 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 func- tion 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 spec- ified subroutine. INHERITANCE SQL::Statement::Function ISA SQL::Statement::Term METHODS new Instantiates a new "SQL::Statement::Function::UserFunc" instance. value Invokes the given soubroutine 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 aren't 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::State- ment::Term instance. If omitted, everything to the end of the string is returned. \@params Expected to be an array with exact 1 element (more aren't 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) 2009,2010 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 v5.8.8 2010-05-06 SQL::Statement::Function(3) |