/ 
Wasm-0.23
River stage one • 1 direct dependent • 1 total dependent
/ Wasm::Wasmtime::Func

NAME

Wasm::Wasmtime::Func - Wasmtime function class

VERSION

version 0.23

SYNOPSIS

# Call a wasm function from Perl
use Wasm::Wasmtime;

my $store = Wasm::Wasmtime::Store->new;
my $module = Wasm::Wasmtime::Module->new( $store->engine, wat => q{
  (module
   (func (export "add") (param i32 i32) (result i32)
     local.get 0
     local.get 1
     i32.add)
  )
});

my $instance = Wasm::Wasmtime::Instance->new($module, $store);
my $add = $instance->exports->add;
print $add->call(1,2), "\n";  # 3

# Call Perl from Wasm
use Wasm::Wasmtime;

my $store = Wasm::Wasmtime::Store->new;
my $module = Wasm::Wasmtime::Module->new( $store->engine, wat => q{
  (module
    (func $hello (import "" "hello"))
    (func (export "run") (call $hello))
  )
});

my $hello = Wasm::Wasmtime::Func->new(
  $store,
  Wasm::Wasmtime::FuncType->new([],[]),
  sub { print "hello world!\n" },
);

my $instance = Wasm::Wasmtime::Instance->new($module, $store, [$hello]);
$instance->exports->run->call(); # hello world!

DESCRIPTION

WARNING: WebAssembly and Wasmtime are a moving target and the interface for these modules is under active development. Use with caution.

This class represents a function, and can be used to either call a WebAssembly function from Perl, or to create a callback for calling a Perl function from WebAssembly.

CONSTRUCTOR

new

my $func = Wasm::Wasmtime::Func->new(
  $store,               # Wasm::Wasmtime::Store
  \@params, \@results,  # array reference for function signature
  \&callback,           # code reference
);
my $func = Wasm::Wasmtime::Func->new(
  $store,      # Wasm::Wasmtime::Store
  $functype,   # Wasm::Wasmtime::FuncType
  \&callback,  # code reference
);

Creates a function instance, which can be used to call Perl from WebAssembly. See Wasm::Wasmtime::FuncType for details on how to specify the function signature.

METHODS

call

my @results = $func->call(@params);
my @results = $func->(@params);

Calls the function instance. This can be used to call either Perl functions created with new as above, or call WebAssembly functions from Perl. As a convenience you can call the function by using the function instance like a code reference.

If there is a trap during the call it will throw an exception. In list context all of the results are returned as a list. In scalar context just the first result (if any) is returned.

attach

$func->attach($name);
$func->attach($package, $name);

Attach the function as a Perl subroutine. If $package is not specified, then the caller's package will be used.

type

my $functype = $func->type;

Returns the Wasm::Wasmtime::FuncType instance which includes the function signature.

param_arity

my $num = $func->param_arity;

Returns the number of arguments the function takes.

result_arity

my $num = $func->param_arity;

Returns the number of results the function returns.

SEE ALSO

Wasm
Wasm::Wasmtime

AUTHOR

Graham Ollis <plicease@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2020-2022 by Graham Ollis.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.