This is a homepage for the Pliant Perl binding whose goal is to give Pliant access to CPAN, a large library of modules written in Perl. This is accomplished by embedding a perl interpreter inside pliant.
With this binding you can:
Recent changes are listed in CHANGES.txt.
Binaries:
More on CVS at the pliant-perl cvs sourceforge page.
Here is a working sample program to access a PostgreSQL database through perl's DBI layer. More examples exist in 'pliantx/language/perl/examples' directory.
module "/pliantx/lexer/multiline_string.pli"
module "/pliantx/language/perl.pli" # THE KEY MODULE TO USE
module "/pliant/language/compiler.pli"
perl_eval {{ use DBI; }}
gvar PerlScalar dbh ref_records
dbh := perl_static DBI connect "dbi:Pg:dbname=test_db" "" ""
ref_records := dbh selectall_arrayref "select * from products;"
gvar PerlArray records := ref_records array #deref
gvar PerlArray record
for (gvar Int i) 0 records:size-1
console "Record " i eol
record := records:i:array
for (gvar Int j) 0 record:size-1
console j ": " record:j eol
dbh disconnect
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Here's the output:
Record 0 0: A1 1: Apple Record 1 0: A2 1: Orange Record 2 0: A3 1: Banana Record 3 0: A4 1: Peach
module "/pliantx/lexer/multiline_string.pli"
module "/pliant/language/compiler.pli"
module "/pliantx/language/perl.pli"
perl_eval {{
sub run_callback {
my $sub = $_[0];
print "in run_callback $sub\n";
my @a = &$sub("a","b","c");
print "retval = @a\n";
}
}}
function hello array -> retval
arg_rw PerlArray array
arg PerlArray retval
console "Inside hello" eol
each (var PerlScalar parameter) array
console "Got arg = " parameter eol
# set return value
retval:0 := 1
retval:1 := "a"
perl run_callback perl_callback:hello
perl_define "hello" hello
perl_eval "hello(1 .. 5);"
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in run_callback CODE(0x8083c80) Inside hello Got arg = a Got arg = b Got arg = c retval = 1 a Inside hello Got arg = 1 Got arg = 2 Got arg = 3 Got arg = 4 Got arg = 5
When the {{ and }} syntax comes in the beginning of a file, make sure that there is a line with some Pliant instruction above it. In above example we have two lines for the "module" keywords for compiler.pli and perl.pli packages. The module line for the multiline_string.pli module does not count, because this module defines the {{ and }} syntax.
If in the example above, the module lines were reordered such that the multiline module came last, the program would not compile. Therefore, as a general practice, use the multiline_string.pli module before the perl.pli module.
If your file only has one module directive at the top, which presumably includes perl and multiline modules as submodules, you need to put a dummy line before a use of {{ }} when it is at the top of the file. You can put "true" by itself on a line, for example:
# start of file
module "my_util_module.pli"
true
perl_eval {{
print "works\n";
}}
#...
module "/pliantx/lexer/multiline_string.pli"
module "/pliant/language/compiler.pli"
module "/pliantx/language/perl.pli"
perl_eval {{
package Parent;
sub new {
return bless {},
shift();
}
sub dump {
my $self = shift;
print $self->{message}, "\n";
}
package T;
our @ISA = qw(Parent);
}}
perl_function new_T classname -> self
arg Str classname ; arg PerlScalar self
self := perl_ref (var PerlHash hash)
self bless classname
self:hash:"message" := "hello"
self:hash:"_data" := 10000 # or memory address of some Pliant data
perl_define "T::new" new_T
gvar PerlScalar t := perl_new T
t dump
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# this shows how to use the WxWindows C++ library through its Perl binding
module "/pliantx/lexer/multiline_string.pli"
module "/pliant/language/compiler.pli"
module "/pliantx/language/perl.pli"
perl_eval {{
use strict;
use Wx;
use Data::Dumper;
# every Wx program must have a Wx::App-derived class
package MyApp;
use vars qw(@ISA);
@ISA = qw(Wx::App); }}
perl_function MyApp_OnInit self -> retval
arg PerlScalar self retval
var PerlScalar frame := perl_new MyFrame
self SetTopWindow frame
frame Show 1
retval := 1
perl_define "MyApp::OnInit" MyApp_OnInit
perl_eval {{
package MyFrame;
use Wx::Event;
@MyFrame::ISA = qw(Wx::Frame); }}
gvar PerlScalar wxDefaultPosition := perl "Wx::wxDefaultPosition"
gvar PerlScalar wxITALIC_FONT := perl "Wx::wxITALIC_FONT"
# helper function
function wx_vec x y -> point
arg Float x y
arg PerlScalar point
var PerlArray pair
pair 0 := x
pair 1 := y
point := perl_ref pair
perl_function MyFrame_OnPaint self event -> retval
arg PerlScalar self event retval
var PerlScalar dc := perl_new "Wx::PaintDC" self
dc SetFont wxITALIC_FONT
dc DrawText "Hello, world!" 10 10
perl_define "MyFrame::OnPaint" MyFrame_OnPaint
perl_function new_MyFrame classname -> self
arg PerlScalar classname self
self := perl_super MyFrame new perl_undef -1 "Hello, world!" wxDefaultPosition (wx_vec 350 100)
perl 'Wx::Event::EVT_PAINT' self perl_callback:MyFrame_OnPaint
perl_define "MyFrame::new" new_MyFrame
# MAIN:
gvar PerlScalar app := perl_new MyApp
app MainLoop
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The implementation of the pliant-perl project is in the Literate Programming style, using the noweb tool. Here is a noweb syntax file nw.vim. Drop it into $HOME/.vim/syntax/ directory and edit it to match the location of perl and pliant syntax files on your system.
Configure vim to associate syntax files with extensions .pli and, if you want, .nw. To do this, copy filetype.vim from the vim's install direcotry, and put it into $HOME/.vim. Edit it and add,
" Pliant au BufNewFile,BufRead *.pli setf pliant " NOWEB au BufNewFile,BufRead *.nw setf nwThere is probably a better way to do this, but that worked for me.
perl func_name arg1 arg2 ... perl obj method_name arg1 arg2 ...Here "obj" is a blessed PerlScalar. You don't have to use the "perl" keyword when invoking a method on a constructed object. It will automatically figure out that this is a perl call, because obj is of type PerlScalar:
obj method_name arg1 arg2 ...
dbh := perl_static DBI connect data_source data_username data_password # the following two are equivalent obj := perl_new T arg1 arg2 ... obj := perl_static T new arg1 arg2 ... # the following two are equivalent obj := perl_super T new arg1 arg2 ... obj := perl_static T "T::SUPER::new" arg1 arg2 ...The lasts example is usefull to call the parent constructor in the implementation of T::new (see wxperl.pli example, MyFrame::new implementation).
perl_function non_perl_aware i j k -> r
arg Str i j ; arg Int k ; arg Str r
console i j k eol
r := 10
perl_function somewhat_perl_aware obj i j -> r
arg PerlScalar obj ; arg Int i j r
obj dump #call method on perl object
console i j eol
r := 20
function very_perl_aware args -> retval
arg PerlArray args retval
arg PerlScalar obj := args 0
arg Int i j
i := args 1 ; j := args 2
obj dump
console i j eol
retval 0 := 20
# retval 1 := 30 # return multiple values
perl iterate_over_datastructure perl_callback:non_perl_aware
perl iterate_another_datastructure perl_callback:somewhat_perl_aware
perl iterate_another_datastructure perl_callback:very_perl_aware
Here is what the 'perl_function' keyword does in the background. It will
create a function with the same name but with the signature (PerlArray
-> PerlArray) which will delegate the call to the actual function.
perl_define "hello" hello perl_define "T::new" new_TThe Pliant function must either be declared with 'perl_function' or must receive a PerlArray and return a PerlArray.
gvar PerlScalar callback := perl_callback hello perl run_callback callback
var PerlHash hash var PerlScalar r_hash := perl_ref hash r_hash:hash "month" := "May"
perl_eval {{
use Data::Dumper;
sub run_callback {
my $sub = shift;
print "in run_callback $sub\n";
my @a = &$sub("a","b","c");
print "retval = @a\n";
\}}}
( R E I T M A N a t S H A W o C A )