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((* extends 'article.tplx' *))

((* block commands *))
((( super() )))
% define custom margins
\geometry{verbose,tmargin=1in,bmargin=1in,lmargin=1in,rmargin=1in}
\renewcommand{\includegraphics}[1]{\Oldincludegraphics[width=\maxwidth]{#1}}
((* endblock commands *))

((* block predoc *))

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#!/bin/sh
#
# Generate PDF file from ipynb notebook.
# Several tricks are done to post-process the latex files.

if [ $# -ne 1 ]; then
    echo "Usage: `basename $0` filename"
    exit 1
fi

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julia> import Base: promote_rule, convert

julia> struct USD 
         value
       end

julia> struct Painting
         rating
       end 

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a
x
x
x
x
x
x
x
x
x

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Custom cache

Generic function

julia> const fib_cache = Dict()
Dict{Any,Any} with 0 entries

julia> _fib(n) = n < 3 ? 1 : fib(n-1) + fib(n-2)
_fib (generic function with 1 method)

tk3369

Some notes from Julia Slack

My initial question was why this expression returns false:

julia> Vector{Any} === Vector
false

The answer is quite simply that Vector{Any} is just like any other Vector{T}, for which is a subtype of Vector. Then, we wonder what is Vector.

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What are functors?

Functors are types that can be mapped over.

Two laws (https://wiki.haskell.org/Functor#Functor_Laws):

1. mapping an identity function over a functor would return the same functor
2. mapping function g then f is equivalent to mapping the composed function (f ∘ g)

fmap is a mapping function that operates on functors. It can be defined for specific objects so that the provided mapping function can be applied in the

tk3369

julia> macro name(ex)
           ex.head === :function || 
               error("can be used for function defintions only")
           name = ex.args[1].args[1]
           assignment = :(local __NAME__ = $name)
           pushfirst!(ex.args[2].args, assignment)
           return ex
       end
@name (macro with 1 method)

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From Mason Protter in Slack:

struct FullyCurried end

macro curried(fdef)
    f = fdef.args[1].args[1]
    fargs = fdef.args[1].args[2:end]
    arity = length(fargs)
 body = fdef.args[2]

tk3369

using Plots

function batman(; lw = 4)
    let sqrt = x -> x > 0 ? Base.sqrt(x) : NaN
        v1(x) = 2*sqrt(-abs(abs(x)-1)*abs(3-abs(x))/((abs(x)-1)*(3-abs(x)))) * (1+abs(abs(x)-3)/(abs(x)-3)) * sqrt(1-(x/7)^2)+(5+0.97(abs(x-.5)+abs(x+.5))-3(abs(x-.75)+abs(x+.75))) * (1+abs(1-abs(x))/(1-abs(x))) 
        v2(x) = (2.71052 + 1.5 - 0.5 * abs(x) - 1.35526 * sqrt(4-(abs(x)-1)^2)) * sqrt(abs(abs(x)-1)/(abs(x)-1)) + 0.9
        v3(x) = (-3)*sqrt(1-(x/7)^2)*sqrt(abs(abs(x)-4)/(abs(x)-4))
        v4(x) = abs(x/2)-0.0913722*x^2-3+sqrt(1-(abs(abs(x)-2)-1)^2)

        x = -8:0.0005:8