In [1]:

    

using AudioIO, SIUnits, SIUnits.ShortUnits #Load some Julia packages

immutable note{T<:Real}      #A user-defined data type
    pitch::quantity(T, Hz)   #This field has units of Hz
    duration::quantity(T, s)
    timbre::Function         #This field is a function
end

#Generate a time-domain sample of a sound wave
function waveform{T<:Real}(A::note{T}; samplingrate::quantity(T, Hz)=44100.0Hz)
   Float32[A.timbre(2π*A.pitch*t) for t in 0s:1/samplingrate:A.duration]
end


    

    
Out[1]:





waveform (generic function with 1 method)

In [3]:

    

#AudioIO knows how to play a waveform using libportaudio
import AudioIO.play
#Now we define what it means to play a note
play(A::note)=play(waveform(A))
play(note(440.0Hz, 2.0s, x->sin(x)+0.1*sin(2x)+0.01*sin(4x)))


    

    
Out[3]:





ArrayPlayer(true,[0.0f0,0.07763475f0,0.15467185f0,0.2305274f0,0.30464435f0,0.37650433f0,0.44563764f0,0.51163095f0,0.57413256f0,0.63285464f0  …  -0.63285464f0,-0.57413256f0,-0.51163095f0,-0.44563764f0,-0.37650433f0,-0.30464435f0,-0.2305274f0,-0.15467185f0,-0.07763475f0,1.5564812f-13],1)

In [38]:

    

phase{T}(pitch::quantity(T, Hz), duration::quantity(T, s)) = pitch*duration
code_native(phase, (quantity(Float32, Hz), quantity(Float32, s)))


    

    




	.section	__TEXT,__text,regular,pure_instructions
Filename: In[38]
Source line: 1
	push	RBP
	mov	RBP, RSP
Source line: 1
	movabs	RAX, 4395453136
	call	RAX
	pop	RBP
	ret

In [15]:

    

#This calls libc's getenv() to query the SHELL environment variable
myshell = ccall((:getenv, "libc"), Ptr{Uint8}, (Ptr{Uint8},), "SHELL")


    

    
Out[15]:





Ptr{Uint8} @0x00007fff5c716c55

In [16]:

    

bytestring(myshell) #C string -> Julia string


    

    
Out[16]:





"/bin/bash"