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linguist/samples/Nit/extern_methods.nit
Lucas Bajolet dd557ed00a Added examples for Nit to samples.
Signed-off-by: Lucas Bajolet <r4pass@hotmail.com>
2014-06-27 10:49:29 -04:00

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# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Copyright 2012-2013 Alexis Laferrière <alexis.laf@xymus.net>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# This module illustrates some uses of the FFI, specifically
# how to use extern methods. Which means to implement a Nit method in C.
module extern_methods
redef enum Int
# Returns self'th fibonnaci number
# implemented here in C for optimization purposes
fun fib : Int import fib `{
if ( recv < 2 )
return recv;
else
return Int_fib( recv-1 ) + Int_fib( recv-2 );
`}
# System call to sleep for "self" seconds
fun sleep `{
sleep( recv );
`}
# Return atan2l( self, x ) from libmath
fun atan_with( x : Int ) : Float `{
return atan2( recv, x );
`}
# This method callback to Nit methods from C code
# It will use from C code:
# * the local fib method
# * the + operator, a method of Int
# * to_s, a method of all objects
# * String.to_cstring, a method of String to return an equivalent char*
fun foo import fib, +, to_s, String.to_cstring `{
long recv_fib = Int_fib( recv );
long recv_plus_fib = Int__plus( recv, recv_fib );
String nit_string = Int_to_s( recv_plus_fib );
char *c_string = String_to_cstring( nit_string );
printf( "from C: self + fib(self) = %s\n", c_string );
`}
# Equivalent to foo but written in pure Nit
fun bar do print "from Nit: self + fib(self) = {self+self.fib}"
end
print 12.fib
print "sleeping 1 second..."
1.sleep
print 100.atan_with( 200 )
8.foo
8.bar