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Merge pull request #3201 from inkydragon/Julia_1.0
[Julia/en] Update output for Julia 1.0
This commit is contained in:
Divay Prakash
GitHub
commit
4c36ee6943
@ -8,12 +8,12 @@ filename: learnjulia.jl
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---
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Julia is a new homoiconic functional language focused on technical computing.
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While having the full power of homoiconic macros, first-class functions, and low-level control, Julia is as easy to learn and use as Python.
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While having the full power of homoiconic macros, first-class functions,
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and low-level control, Julia is as easy to learn and use as Python.
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This is based on Julia 1.0.0
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```julia
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# Single line comments start with a hash (pound) symbol.
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#= Multiline comments can be written
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by putting '#=' before the text and '=#'
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@ -27,17 +27,17 @@ This is based on Julia 1.0.0
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# Everything in Julia is an expression.
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# There are several basic types of numbers.
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3 # => 3 (Int64)
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3.2 # => 3.2 (Float64)
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2 + 1im # => 2 + 1im (Complex{Int64})
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2 // 3 # => 2 // 3 (Rational{Int64})
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typeof(3) # => Int64
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typeof(3.2) # => Float64
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typeof(2 + 1im) # => Complex{Int64}
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typeof(2 // 3) # => Rational{Int64}
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# All of the normal infix operators are available.
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1 + 1 # => 2
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8 - 1 # => 7
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10 * 2 # => 20
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35 / 5 # => 7.0
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5 / 2 # => 2.5 # dividing integers always results in a Float64
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10 / 2 # => 5.0 # dividing integers always results in a Float64
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div(5, 2) # => 2 # for a truncated result, use div
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5 \ 35 # => 7.0
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2^2 # => 4 # power, not bitwise xor
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@ -88,7 +88,9 @@ false
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# Strings are UTF8 encoded. Only if they contain only ASCII characters can
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# they be safely indexed.
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ascii("This is a string")[1] # => 'T' # Julia indexes from 1
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ascii("This is a string")[1]
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# => 'T': ASCII/Unicode U+0054 (category Lu: Letter, uppercase)
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# Julia indexes from 1
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# Otherwise, iterating over strings is recommended (map, for loops, etc).
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# $ can be used for string interpolation:
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@ -100,7 +102,7 @@ using Printf
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@printf "%d is less than %f\n" 4.5 5.3 # => 5 is less than 5.300000
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# Printing is easy
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println("I'm Julia. Nice to meet you!")
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println("I'm Julia. Nice to meet you!") # => I'm Julia. Nice to meet you!
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# String can be compared lexicographically
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"good" > "bye" # => true
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@ -146,19 +148,19 @@ SomeOtherVar123! = 6 # => 6
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# functions are sometimes called mutating functions or in-place functions.
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# Arrays store a sequence of values indexed by integers 1 through n:
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a = Int64[] # => 0-element Int64 Array
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a = Int64[] # => 0-element Array{Int64,1}
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# 1-dimensional array literals can be written with comma-separated values.
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b = [4, 5, 6] # => 3-element Int64 Array: [4, 5, 6]
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b = [4; 5; 6] # => 3-element Int64 Array: [4, 5, 6]
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b[1] # => 4
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b = [4, 5, 6] # => 3-element Array{Int64,1}: [4, 5, 6]
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b = [4; 5; 6] # => 3-element Array{Int64,1}: [4, 5, 6]
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b[1] # => 4
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b[end] # => 6
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# 2-dimensional arrays use space-separated values and semicolon-separated rows.
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matrix = [1 2; 3 4] # => 2x2 Int64 Array: [1 2; 3 4]
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matrix = [1 2; 3 4] # => 2×2 Array{Int64,2}: [1 2; 3 4]
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# Arrays of a particular type
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b = Int8[4, 5, 6] # => 3-element Int8 Array: [4, 5, 6]
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b = Int8[4, 5, 6] # => 3-element Array{Int8,1}: [4, 5, 6]
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# Add stuff to the end of a list with push! and append!
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push!(a, 1) # => [1]
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@ -168,10 +170,12 @@ push!(a, 3) # => [1,2,4,3]
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append!(a, b) # => [1,2,4,3,4,5,6]
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# Remove from the end with pop
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pop!(b) # => 6 and b is now [4,5]
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pop!(b) # => 6
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b # => [4,5]
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# Let's put it back
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push!(b, 6) # b is now [4,5,6] again.
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push!(b, 6) # => [4,5,6]
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b # => [4,5,6]
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a[1] # => 1 # remember that Julia indexes from 1, not 0!
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@ -180,21 +184,37 @@ a[1] # => 1 # remember that Julia indexes from 1, not 0!
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a[end] # => 6
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# we also have popfirst! and pushfirst!
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popfirst!(a) # => 1 and a is now [2,4,3,4,5,6]
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popfirst!(a) # => 1
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a # => [2,4,3,4,5,6]
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pushfirst!(a, 7) # => [7,2,4,3,4,5,6]
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a # => [7,2,4,3,4,5,6]
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# Function names that end in exclamations points indicate that they modify
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# their argument.
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arr = [5,4,6] # => 3-element Int64 Array: [5,4,6]
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sort(arr) # => [4,5,6]; arr is still [5,4,6]
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sort!(arr) # => [4,5,6]; arr is now [4,5,6]
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arr = [5,4,6] # => 3-element Array{Int64,1}: [5,4,6]
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sort(arr) # => [4,5,6]
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arr # => [5,4,6]
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sort!(arr) # => [4,5,6]
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arr # => [4,5,6]
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# Looking out of bounds is a BoundsError
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try
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a[0]
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# => BoundsError: attempt to access 7-element Array{Int64,1} at index [0]
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# => ERROR: BoundsError: attempt to access 7-element Array{Int64,1} at
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# index [0]
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# => Stacktrace:
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# => [1] getindex(::Array{Int64,1}, ::Int64) at .\array.jl:731
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# => [2] top-level scope at none:0
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# => [3] ...
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# => in expression starting at ...\LearnJulia.jl:180
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a[end + 1]
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# => BoundsError: attempt to access 7-element Array{Int64,1} at index [8]
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# => ERROR: BoundsError: attempt to access 7-element Array{Int64,1} at
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# index [8]
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# => Stacktrace:
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# => [1] getindex(::Array{Int64,1}, ::Int64) at .\array.jl:731
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# => [2] top-level scope at none:0
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# => [3] ...
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# => in expression starting at ...\LearnJulia.jl:188
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catch e
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println(e)
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end
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@ -204,7 +224,8 @@ end
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# find these files.
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# You can initialize arrays from ranges
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a = [1:5;] # => 5-element Int64 Array: [1,2,3,4,5]
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a = [1:5;] # => 5-element Array{Int64,1}: [1,2,3,4,5]
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a2 = [1:5] # => 1-element Array{UnitRange{Int64},1}: [1:5]
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# You can look at ranges with slice syntax.
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a[1:3] # => [1, 2, 3]
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@ -212,11 +233,13 @@ a[2:end] # => [2, 3, 4, 5]
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# Remove elements from an array by index with splice!
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arr = [3,4,5]
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splice!(arr, 2) # => 4 ; arr is now [3,5]
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splice!(arr, 2) # => 4
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arr # => [3,5]
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# Concatenate lists with append!
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b = [1,2,3]
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append!(a, b) # Now a is [1, 2, 3, 4, 5, 1, 2, 3]
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append!(a, b) # => [1, 2, 3, 4, 5, 1, 2, 3]
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a # => [1, 2, 3, 4, 5, 1, 2, 3]
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# Check for existence in a list with in
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in(1, a) # => true
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@ -225,39 +248,50 @@ in(1, a) # => true
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length(a) # => 8
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# Tuples are immutable.
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tup = (1, 2, 3) # => (1,2,3) # an (Int64,Int64,Int64) tuple.
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tup[1] # => 1
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tup = (1, 2, 3) # => (1,2,3)
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typeof(tup) # => Tuple{Int64,Int64,Int64}
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tup[1] # => 1
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try
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tup[1] = 3 # => ERROR: no method setindex!((Int64,Int64,Int64),Int64,Int64)
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tup[1] = 3
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# => ERROR: MethodError: no method matching
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# setindex!(::Tuple{Int64,Int64,Int64}, ::Int64, ::Int64)
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catch e
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println(e)
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end
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# Many array functions also work on tuples
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length(tup) # => 3
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tup[1:2] # => (1,2)
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length(tup) # => 3
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tup[1:2] # => (1,2)
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in(2, tup) # => true
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# You can unpack tuples into variables
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a, b, c = (1, 2, 3) # => (1,2,3) # a is now 1, b is now 2 and c is now 3
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a, b, c = (1, 2, 3) # => (1,2,3)
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a # => 1
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b # => 2
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c # => 3
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# Tuples are created even if you leave out the parentheses
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d, e, f = 4, 5, 6 # => (4,5,6)
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d # => 4
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e # => 5
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f # => 6
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# A 1-element tuple is distinct from the value it contains
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(1,) == 1 # => false
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(1,) == 1 # => false
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(1) == 1 # => true
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# Look how easy it is to swap two values
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e, d = d, e # => (5,4) # d is now 5 and e is now 4
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e, d = d, e # => (5,4)
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d # => 5
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e # => 4
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# Dictionaries store mappings
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empty_dict = Dict() # => Dict{Any,Any}()
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empty_dict = Dict() # => Dict{Any,Any} with 0 entries
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# You can create a dictionary using a literal
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filled_dict = Dict("one" => 1, "two" => 2, "three" => 3)
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# => Dict{String,Int64}
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# => Dict{String,Int64} with 3 entries:
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# => "two" => 2, "one" => 1, "three" => 3
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# Look up values with []
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filled_dict["one"] # => 1
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@ -265,12 +299,13 @@ filled_dict["one"] # => 1
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# Get all keys
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keys(filled_dict)
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# => Base.KeySet for a Dict{String,Int64} with 3 entries. Keys:
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# "two", "one", "three"
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# => "two", "one", "three"
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# Note - dictionary keys are not sorted or in the order you inserted them.
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# Get all values
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values(filled_dict)
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# => Base.ValueIterator{Dict{String,Int64}} with 3 entries. Values: 2, 1, 3
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# => Base.ValueIterator for a Dict{String,Int64} with 3 entries. Values:
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# => 2, 1, 3
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# Note - Same as above regarding key ordering.
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# Check for existence of keys in a dictionary with in, haskey
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@ -281,7 +316,7 @@ haskey(filled_dict, 1) # => false
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# Trying to look up a non-existent key will raise an error
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try
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filled_dict["four"] # => KeyError: key "four" not found
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filled_dict["four"] # => ERROR: KeyError: key "four" not found
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catch e
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println(e)
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end
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@ -292,7 +327,7 @@ get(filled_dict, "one", 4) # => 1
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get(filled_dict, "four", 4) # => 4
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# Use Sets to represent collections of unordered, unique values
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empty_set = Set() # => Set{Any}()
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empty_set = Set() # => Set(Any[])
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# Initialize a set with values
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filled_set = Set([1, 2, 2, 3, 4]) # => Set([4, 2, 3, 1])
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@ -300,15 +335,14 @@ filled_set = Set([1, 2, 2, 3, 4]) # => Set([4, 2, 3, 1])
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push!(filled_set, 5) # => Set([4, 2, 3, 5, 1])
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# Check if the values are in the set
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in(2, filled_set) # => true
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in(2, filled_set) # => true
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in(10, filled_set) # => false
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# There are functions for set intersection, union, and difference.
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other_set = Set([3, 4, 5, 6]) # => Set([4, 3, 5, 6])
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intersect(filled_set, other_set) # => Set([4, 3, 5])
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union(filled_set, other_set) # => Set([4, 2, 3, 5, 6, 1])
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setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set([4, 1])
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other_set = Set([3, 4, 5, 6]) # => Set([4, 3, 5, 6])
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intersect(filled_set, other_set) # => Set([4, 3, 5])
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union(filled_set, other_set) # => Set([4, 2, 3, 5, 6, 1])
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setdiff(Set([1,2,3,4]), Set([2,3,5])) # => Set([4, 1])
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####################################################
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## 3. Control Flow
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@ -327,43 +361,38 @@ else # The else clause is optional too.
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end
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# => prints "some var is smaller than 10"
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# For loops iterate over iterables.
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# Iterable types include Range, Array, Set, Dict, and AbstractString.
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for animal = ["dog", "cat", "mouse"]
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println("$animal is a mammal")
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# You can use $ to interpolate variables or expression into strings
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end
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# prints:
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# dog is a mammal
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# cat is a mammal
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# mouse is a mammal
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# => dog is a mammal
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# => cat is a mammal
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# => mouse is a mammal
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# You can use 'in' instead of '='.
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for animal in ["dog", "cat", "mouse"]
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println("$animal is a mammal")
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end
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# prints:
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# dog is a mammal
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# cat is a mammal
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# mouse is a mammal
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# => dog is a mammal
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# => cat is a mammal
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# => mouse is a mammal
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for pair in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal")
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from, to = pair
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println("$from is a $to")
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end
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# prints:
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# dog is a mammal
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# cat is a mammal
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# mouse is a mammal
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# => mouse is a mammal
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# => cat is a mammal
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# => dog is a mammal
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for (k, v) in Dict("dog" => "mammal", "cat" => "mammal", "mouse" => "mammal")
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println("$k is a $v")
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end
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# prints:
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# dog is a mammal
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# cat is a mammal
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# mouse is a mammal
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# => mouse is a mammal
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# => cat is a mammal
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# => dog is a mammal
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# While loops loop while a condition is true
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let x = 0
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@ -372,11 +401,10 @@ let x = 0
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x += 1 # Shorthand for x = x + 1
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end
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end
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# prints:
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# 0
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# 1
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# 2
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# 3
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# => 0
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# => 1
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# => 2
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# => 3
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# Handle exceptions with a try/catch block
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try
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@ -386,15 +414,14 @@ catch e
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end
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# => caught it ErrorException("help")
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####################################################
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## 4. Functions
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####################################################
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# The keyword 'function' creates new functions
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#function name(arglist)
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# body...
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#end
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# function name(arglist)
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# body...
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# end
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function add(x, y)
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println("x is $x and y is $y")
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@ -402,14 +429,16 @@ function add(x, y)
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x + y
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end
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add(5, 6) # => 11 after printing out "x is 5 and y is 6"
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add(5, 6)
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# => x is 5 and y is 6
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# => 11
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# Compact assignment of functions
|
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f_add(x, y) = x + y # => "f (generic function with 1 method)"
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f_add(x, y) = x + y # => f_add (generic function with 1 method)
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f_add(3, 4) # => 7
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# Function can also return multiple values as tuple
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fn(x, y) = x + y, x - y
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fn(x, y) = x + y, x - y # => fn (generic function with 1 method)
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fn(3, 4) # => (7, -1)
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# You can define functions that take a variable number of
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@ -436,13 +465,14 @@ add(x...) # this is equivalent to add(5,6)
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function defaults(a, b, x=5, y=6)
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return "$a $b and $x $y"
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end
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# => defaults (generic function with 3 methods)
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defaults('h', 'g') # => "h g and 5 6"
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defaults('h', 'g', 'j') # => "h g and j 6"
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defaults('h', 'g', 'j', 'k') # => "h g and j k"
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try
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defaults('h') # => ERROR: no method defaults(Char,)
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defaults() # => ERROR: no methods defaults()
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defaults('h') # => ERROR: MethodError: no method matching defaults(::Char)
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defaults() # => ERROR: MethodError: no method matching defaults()
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catch e
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println(e)
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end
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@ -451,10 +481,11 @@ end
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function keyword_args(;k1=4, name2="hello") # note the ;
|
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return Dict("k1" => k1, "name2" => name2)
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end
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# => keyword_args (generic function with 1 method)
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keyword_args(name2="ness") # => ["name2"=>"ness","k1"=>4]
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keyword_args(k1="mine") # => ["k1"=>"mine","name2"=>"hello"]
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||||
keyword_args() # => ["name2"=>"hello","k1"=>4]
|
||||
keyword_args(name2="ness") # => ["name2"=>"ness", "k1"=>4]
|
||||
keyword_args(k1="mine") # => ["name2"=>"hello", "k1"=>"mine"]
|
||||
keyword_args() # => ["name2"=>"hello", "k1"=>4]
|
||||
|
||||
# You can combine all kinds of arguments in the same function
|
||||
function all_the_args(normal_arg, optional_positional_arg=2; keyword_arg="foo")
|
||||
@ -462,12 +493,12 @@ function all_the_args(normal_arg, optional_positional_arg=2; keyword_arg="foo")
|
||||
println("optional arg: $optional_positional_arg")
|
||||
println("keyword arg: $keyword_arg")
|
||||
end
|
||||
# => all_the_args (generic function with 2 methods)
|
||||
|
||||
all_the_args(1, 3, keyword_arg=4)
|
||||
# prints:
|
||||
# normal arg: 1
|
||||
# optional arg: 3
|
||||
# keyword arg: 4
|
||||
# => normal arg: 1
|
||||
# => optional arg: 3
|
||||
# => keyword arg: 4
|
||||
|
||||
# Julia has first class functions
|
||||
function create_adder(x)
|
||||
@ -476,6 +507,7 @@ function create_adder(x)
|
||||
end
|
||||
return adder
|
||||
end
|
||||
# => create_adder (generic function with 1 method)
|
||||
|
||||
# This is "stabby lambda syntax" for creating anonymous functions
|
||||
(x -> x > 2)(3) # => true
|
||||
@ -484,6 +516,7 @@ end
|
||||
function create_adder(x)
|
||||
y -> x + y
|
||||
end
|
||||
# => create_adder (generic function with 1 method)
|
||||
|
||||
# You can also name the internal function, if you want
|
||||
function create_adder(x)
|
||||
@ -492,9 +525,11 @@ function create_adder(x)
|
||||
end
|
||||
adder
|
||||
end
|
||||
# => create_adder (generic function with 1 method)
|
||||
|
||||
add_10 = create_adder(10)
|
||||
add_10(3) # => 13
|
||||
add_10 = create_adder(10) # => (::getfield(Main, Symbol("#adder#11")){Int64})
|
||||
# (generic function with 1 method)
|
||||
add_10(3) # => 13
|
||||
|
||||
|
||||
# There are built-in higher order functions
|
||||
@ -502,8 +537,8 @@ map(add_10, [1,2,3]) # => [11, 12, 13]
|
||||
filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7]
|
||||
|
||||
# We can use list comprehensions
|
||||
[add_10(i) for i = [1, 2, 3]] # => [11, 12, 13]
|
||||
[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13]
|
||||
[add_10(i) for i = [1, 2, 3]] # => [11, 12, 13]
|
||||
[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13]
|
||||
[x for x in [3, 4, 5, 6, 7] if x > 5] # => [6, 7]
|
||||
|
||||
####################################################
|
||||
@ -516,7 +551,7 @@ filter(x -> x > 5, [3, 4, 5, 6, 7]) # => [6, 7]
|
||||
typeof(5) # => Int64
|
||||
|
||||
# Types are first-class values
|
||||
typeof(Int64) # => DataType
|
||||
typeof(Int64) # => DataType
|
||||
typeof(DataType) # => DataType
|
||||
# DataType is the type that represents types, including itself.
|
||||
|
||||
@ -551,32 +586,31 @@ sherekhan = typeof(tigger)(5.6, "fire") # => Tiger(5.6,"fire")
|
||||
abstract type Cat end # just a name and point in the type hierarchy
|
||||
|
||||
# Abstract types cannot be instantiated, but can have subtypes.
|
||||
using InteractiveUtils # defines the subtype and supertype function
|
||||
# For example, Number is an abstract type
|
||||
subtypes(Number) # => 2-element Array{Any,1}:
|
||||
# Complex{T<:Real}
|
||||
# Real
|
||||
# => Complex
|
||||
# => Real
|
||||
subtypes(Cat) # => 0-element Array{Any,1}
|
||||
|
||||
# AbstractString, as the name implies, is also an abstract type
|
||||
subtypes(AbstractString) # 4-element Array{Any,1}:
|
||||
# String
|
||||
# SubString
|
||||
# SubstitutionString
|
||||
# Test.GenericString
|
||||
subtypes(AbstractString) # => 4-element Array{Any,1}:
|
||||
# => String
|
||||
# => SubString
|
||||
# => SubstitutionString
|
||||
# => Test.GenericString
|
||||
|
||||
# Every type has a super type; use the `supertype` function to get it.
|
||||
typeof(5) # => Int64
|
||||
supertype(Int64) # => Signed
|
||||
supertype(Signed) # => Integer
|
||||
typeof(5) # => Int64
|
||||
supertype(Int64) # => Signed
|
||||
supertype(Signed) # => Integer
|
||||
supertype(Integer) # => Real
|
||||
supertype(Real) # => Number
|
||||
supertype(Number) # => Any
|
||||
supertype(Real) # => Number
|
||||
supertype(Number) # => Any
|
||||
supertype(supertype(Signed)) # => Real
|
||||
supertype(Any) # => Any
|
||||
supertype(Any) # => Any
|
||||
# All of these type, except for Int64, are abstract.
|
||||
typeof("fire") # => String
|
||||
supertype(String) # => AbstractString
|
||||
typeof("fire") # => String
|
||||
supertype(String) # => AbstractString
|
||||
# Likewise here with String
|
||||
supertype(SubString) # => AbstractString
|
||||
|
||||
@ -625,23 +659,24 @@ function meow(animal::Tiger)
|
||||
end
|
||||
|
||||
# Testing the meow function
|
||||
meow(tigger) # => "rawwr"
|
||||
meow(tigger) # => "rawwwr"
|
||||
meow(Lion("brown", "ROAAR")) # => "ROAAR"
|
||||
meow(Panther()) # => "grrr"
|
||||
meow(Panther()) # => "grrr"
|
||||
|
||||
# Review the local type hierarchy
|
||||
Tiger <: Cat # => false
|
||||
Lion <: Cat # => true
|
||||
Panther <: Cat # => true
|
||||
Tiger <: Cat # => false
|
||||
Lion <: Cat # => true
|
||||
Panther <: Cat # => true
|
||||
|
||||
# Defining a function that takes Cats
|
||||
function pet_cat(cat::Cat)
|
||||
println("The cat says $(meow(cat))")
|
||||
end
|
||||
# => pet_cat (generic function with 1 method)
|
||||
|
||||
pet_cat(Lion("42")) # => prints "The cat says 42"
|
||||
pet_cat(Lion("42")) # => The cat says 42
|
||||
try
|
||||
pet_cat(tigger) # => ERROR: no method pet_cat(Tiger,)
|
||||
pet_cat(tigger) # => ERROR: MethodError: no method matching pet_cat(::Tiger)
|
||||
catch e
|
||||
println(e)
|
||||
end
|
||||
@ -656,45 +691,54 @@ function fight(t::Tiger, c::Cat)
|
||||
end
|
||||
# => fight (generic function with 1 method)
|
||||
|
||||
fight(tigger, Panther()) # => prints The orange tiger wins!
|
||||
fight(tigger, Lion("ROAR")) # => prints The orange tiger wins!
|
||||
fight(tigger, Panther()) # => The orange tiger wins!
|
||||
fight(tigger, Lion("ROAR")) # => The orange tiger wins!
|
||||
|
||||
# Let's change the behavior when the Cat is specifically a Lion
|
||||
fight(t::Tiger, l::Lion) = println("The $(l.mane_color)-maned lion wins!")
|
||||
# => fight (generic function with 2 methods)
|
||||
|
||||
fight(tigger, Panther()) # => prints The orange tiger wins!
|
||||
fight(tigger, Lion("ROAR")) # => prints The green-maned lion wins!
|
||||
fight(tigger, Panther()) # => The orange tiger wins!
|
||||
fight(tigger, Lion("ROAR")) # => The green-maned lion wins!
|
||||
|
||||
# We don't need a Tiger in order to fight
|
||||
fight(l::Lion, c::Cat) = println("The victorious cat says $(meow(c))")
|
||||
# => fight (generic function with 3 methods)
|
||||
|
||||
fight(Lion("balooga!"), Panther()) # => prints The victorious cat says grrr
|
||||
fight(Lion("balooga!"), Panther()) # => The victorious cat says grrr
|
||||
try
|
||||
fight(Panther(), Lion("RAWR"))
|
||||
# => ERROR: MethodError: no method matching fight(::Panther, ::Lion)
|
||||
# => Closest candidates are:
|
||||
# => fight(::Tiger, ::Lion) at ...
|
||||
# => fight(::Tiger, ::Cat) at ...
|
||||
# => fight(::Lion, ::Cat) at ...
|
||||
# => ...
|
||||
catch e
|
||||
println(e)
|
||||
# => MethodError(fight, (Panther("green"), Lion("green", "RAWR")),
|
||||
# 0x000000000000557b)
|
||||
end
|
||||
|
||||
# Also let the cat go first
|
||||
fight(c::Cat, l::Lion) = println("The cat beats the Lion")
|
||||
# => fight (generic function with 4 methods)
|
||||
|
||||
# This warning is because it's unclear which fight will be called in:
|
||||
try
|
||||
fight(Lion("RAR"), Lion("brown", "rarrr"))
|
||||
# => prints The victorious cat says rarrr
|
||||
# => ERROR: MethodError: fight(::Lion, ::Lion) is ambiguous. Candidates:
|
||||
# => fight(c::Cat, l::Lion) in Main at ...
|
||||
# => fight(l::Lion, c::Cat) in Main at ...
|
||||
# => Possible fix, define
|
||||
# => fight(::Lion, ::Lion)
|
||||
# => ...
|
||||
catch e
|
||||
println(e)
|
||||
# => MethodError(fight, (Lion("green", "RAR"), Lion("brown", "rarrr")),
|
||||
# 0x000000000000557c)
|
||||
end
|
||||
# The result may be different in other versions of Julia
|
||||
|
||||
fight(l::Lion, l2::Lion) = println("The lions come to a tie")
|
||||
fight(Lion("RAR"), Lion("brown", "rarrr")) # => prints The lions come to a tie
|
||||
# => fight (generic function with 5 methods)
|
||||
fight(Lion("RAR"), Lion("brown", "rarrr")) # => The lions come to a tie
|
||||
|
||||
|
||||
# Under the hood
|
||||
@ -705,74 +749,112 @@ square_area(l) = l * l # square_area (generic function with 1 method)
|
||||
square_area(5) # => 25
|
||||
|
||||
# What happens when we feed square_area an integer?
|
||||
code_native(square_area, (Int32,))
|
||||
# .section __TEXT,__text,regular,pure_instructions
|
||||
# Filename: none
|
||||
# Source line: 1 # Prologue
|
||||
# push RBP
|
||||
# mov RBP, RSP
|
||||
# Source line: 1
|
||||
# movsxd RAX, EDI # Fetch l from memory?
|
||||
# imul RAX, RAX # Square l and store the result in RAX
|
||||
# pop RBP # Restore old base pointer
|
||||
# ret # Result will still be in RAX
|
||||
code_native(square_area, (Int32,), syntax = :intel)
|
||||
# .text
|
||||
# ; Function square_area {
|
||||
# ; Location: REPL[116]:1 # Prologue
|
||||
# push rbp
|
||||
# mov rbp, rsp
|
||||
# ; Function *; {
|
||||
# ; Location: int.jl:54
|
||||
# imul ecx, ecx # Square l and store the result in ECX
|
||||
# ;}
|
||||
# mov eax, ecx
|
||||
# pop rbp # Restore old base pointer
|
||||
# ret # Result will still be in EAX
|
||||
# nop dword ptr [rax + rax]
|
||||
# ;}
|
||||
|
||||
code_native(square_area, (Float32,))
|
||||
# .section __TEXT,__text,regular,pure_instructions
|
||||
# Filename: none
|
||||
# Source line: 1
|
||||
# push RBP
|
||||
# mov RBP, RSP
|
||||
# Source line: 1
|
||||
# vmulss XMM0, XMM0, XMM0 # Scalar single precision multiply (AVX)
|
||||
# pop RBP
|
||||
# ret
|
||||
code_native(square_area, (Float32,), syntax = :intel)
|
||||
# .text
|
||||
# ; Function square_area {
|
||||
# ; Location: REPL[116]:1
|
||||
# push rbp
|
||||
# mov rbp, rsp
|
||||
# ; Function *; {
|
||||
# ; Location: float.jl:398
|
||||
# vmulss xmm0, xmm0, xmm0 # Scalar single precision multiply (AVX)
|
||||
# ;}
|
||||
# pop rbp
|
||||
# ret
|
||||
# nop word ptr [rax + rax]
|
||||
# ;}
|
||||
|
||||
code_native(square_area, (Float64,), syntax = :intel)
|
||||
# .text
|
||||
# ; Function square_area {
|
||||
# ; Location: REPL[116]:1
|
||||
# push rbp
|
||||
# mov rbp, rsp
|
||||
# ; Function *; {
|
||||
# ; Location: float.jl:399
|
||||
# vmulsd xmm0, xmm0, xmm0 # Scalar double precision multiply (AVX)
|
||||
# ;}
|
||||
# pop rbp
|
||||
# ret
|
||||
# nop word ptr [rax + rax]
|
||||
# ;}
|
||||
|
||||
code_native(square_area, (Float64,))
|
||||
# .section __TEXT,__text,regular,pure_instructions
|
||||
# Filename: none
|
||||
# Source line: 1
|
||||
# push RBP
|
||||
# mov RBP, RSP
|
||||
# Source line: 1
|
||||
# vmulsd XMM0, XMM0, XMM0 # Scalar double precision multiply (AVX)
|
||||
# pop RBP
|
||||
# ret
|
||||
#
|
||||
# Note that julia will use floating point instructions if any of the
|
||||
# arguments are floats.
|
||||
# Let's calculate the area of a circle
|
||||
circle_area(r) = pi * r * r # circle_area (generic function with 1 method)
|
||||
circle_area(5) # 78.53981633974483
|
||||
|
||||
code_native(circle_area, (Int32,))
|
||||
# .section __TEXT,__text,regular,pure_instructions
|
||||
# Filename: none
|
||||
# Source line: 1
|
||||
# push RBP
|
||||
# mov RBP, RSP
|
||||
# Source line: 1
|
||||
# vcvtsi2sd XMM0, XMM0, EDI # Load integer (r) from memory
|
||||
# movabs RAX, 4593140240 # Load pi
|
||||
# vmulsd XMM1, XMM0, QWORD PTR [RAX] # pi * r
|
||||
# vmulsd XMM0, XMM0, XMM1 # (pi * r) * r
|
||||
# pop RBP
|
||||
# ret
|
||||
#
|
||||
code_native(circle_area, (Int32,), syntax = :intel)
|
||||
# .text
|
||||
# ; Function circle_area {
|
||||
# ; Location: REPL[121]:1
|
||||
# push rbp
|
||||
# mov rbp, rsp
|
||||
# ; Function *; {
|
||||
# ; Location: operators.jl:502
|
||||
# ; Function *; {
|
||||
# ; Location: promotion.jl:314
|
||||
# ; Function promote; {
|
||||
# ; Location: promotion.jl:284
|
||||
# ; Function _promote; {
|
||||
# ; Location: promotion.jl:261
|
||||
# ; Function convert; {
|
||||
# ; Location: number.jl:7
|
||||
# ; Function Type; {
|
||||
# ; Location: float.jl:60
|
||||
# vcvtsi2sd xmm0, xmm0, ecx # Load integer (r) from memory
|
||||
# movabs rax, 497710928 # Load pi
|
||||
# ;}}}}}
|
||||
# ; Function *; {
|
||||
# ; Location: float.jl:399
|
||||
# vmulsd xmm1, xmm0, qword ptr [rax] # pi * r
|
||||
# vmulsd xmm0, xmm1, xmm0 # (pi * r) * r
|
||||
# ;}}
|
||||
# pop rbp
|
||||
# ret
|
||||
# nop dword ptr [rax]
|
||||
# ;}
|
||||
|
||||
code_native(circle_area, (Float64,))
|
||||
# .section __TEXT,__text,regular,pure_instructions
|
||||
# Filename: none
|
||||
# Source line: 1
|
||||
# push RBP
|
||||
# mov RBP, RSP
|
||||
# movabs RAX, 4593140496
|
||||
# Source line: 1
|
||||
# vmulsd XMM1, XMM0, QWORD PTR [RAX]
|
||||
# vmulsd XMM0, XMM1, XMM0
|
||||
# pop RBP
|
||||
# ret
|
||||
#
|
||||
code_native(circle_area, (Float64,), syntax = :intel)
|
||||
# .text
|
||||
# ; Function circle_area {
|
||||
# ; Location: REPL[121]:1
|
||||
# push rbp
|
||||
# mov rbp, rsp
|
||||
# movabs rax, 497711048
|
||||
# ; Function *; {
|
||||
# ; Location: operators.jl:502
|
||||
# ; Function *; {
|
||||
# ; Location: promotion.jl:314
|
||||
# ; Function *; {
|
||||
# ; Location: float.jl:399
|
||||
# vmulsd xmm1, xmm0, qword ptr [rax]
|
||||
# ;}}}
|
||||
# ; Function *; {
|
||||
# ; Location: float.jl:399
|
||||
# vmulsd xmm0, xmm1, xmm0
|
||||
# ;}
|
||||
# pop rbp
|
||||
# ret
|
||||
# nop dword ptr [rax + rax]
|
||||
# ;}
|
||||
```
|
||||
|
||||
## Further Reading
|
||||
|
||||
Loading…
Reference in New Issue
Block a user