firt version

Author: tp2750

.gitignore

@@ -1,3 +1,4 @@
 /Manifest.toml
 /docs/Manifest.toml
 /docs/build/
+*~

Project.toml

@@ -3,6 +3,10 @@ uuid = "41b83a75-29e0-460a-8ec7-27bd549dfa6e"
 authors = ["Thomas Poulsen <ta.poulsen@gmail.com> and contributors"]
 version = "1.0.0-DEV"
 
+[deps]
+EzXML = "8f5d6c58-4d21-5cfd-889c-e3ad7ee6a615"
+HTTP = "cd3eb016-35fb-5094-929b-558a96fad6f3"
+
 [compat]
 julia = "1"
 

README.md

@@ -3,3 +3,68 @@
 [![Stable](https://img.shields.io/badge/docs-stable-blue.svg)](https://tp2750.github.io/ExchangeRates.jl/stable/)
 [![Dev](https://img.shields.io/badge/docs-dev-blue.svg)](https://tp2750.github.io/ExchangeRates.jl/dev/)
 [![Build Status](https://github.com/tp2750/ExchangeRates.jl/actions/workflows/CI.yml/badge.svg?branch=main)](https://github.com/tp2750/ExchangeRates.jl/actions/workflows/CI.yml?query=branch%3Amain)
+
+## Purpose
+
+The purpose of this package is to provide a convenient interface to working with exchange rates.
+
+## Data
+
+The data is downloaded from the European Centtral Bank, when the package is loaded.
+
+It uses this link: <https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml>.
+
+## Barewords
+
+The simples interface looks like this:
+
+``` julia
+julia> 100EUR/DKK
+745.08
+```
+
+This shows that you need 745.08 DKK to have 100 EUR.
+
+This is done by defining and exporting variables `EUR`, `USD`, `DKK` etc (using the cool metraprogramming tools of julia).
+
+Each variable is the exchange rate of `EUR`, so `USD` is the value of 1 USD in EUR. This means that `100USD` is the value of 100 USD in EUR.
+
+Note that this uses the juxtaposition syntax of julia, so the can not be a whitespace between the number and the currency without an explicit multiplication:
+
+``` julia
+julia> 100 DKK
+ERROR: syntax: extra token "DKK" after end of expression
+
+julia> 100 * DKK
+13.421377570193805
+
+```
+
+## Function interface
+
+The package exports a single function `fromto`. 
+It converts from the first argument to the second argument.
+
+``` julia
+julia> fromto(:EUR,:DKK)*100
+745.08
+```
+
+## Unicode
+
+The package knows a few unicode currencies:
+
+* `€` (EUR)
+* `£` (GBP)
+* `¥` (JPY)
+
+but NOT `$`, as `$` has syntactic meaning in julia (string interpolation).
+
+``` julia
+julia> 100€/£
+86.706
+
+julia> fromto(:EUR,:GBP)*100
+86.706
+```
+

docs/make.jl

@@ -15,7 +15,7 @@ makedocs(;
         assets=String[],
     ),
     pages=[
-        "Home" => "index.md",
+        "README" => "index.md",
     ],
 )
 

docs/src/index.md

@@ -0,0 +1 @@
+../../README.md

docs/src/index.md

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 module ExchangeRates
 
-# Write your package code here.
+using EzXML
+using HTTP
+
+include("fromto.jl")
+export exchage_rates, fromto
+
+include("consts.jl")
+# exports EUR, USD, DKK etc
+
 
 end

src/ExchangeRates.jl

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+# Set variables for rates:
+global EUR = 1.0
+eval(Meta.parse(join(["global $(x[1]) = EUR/$(x[2]) " for x in pairs(exchange_rates)], ";")));
+
+# 100EUR/DKK == 745.08
+# 100NOK/DKK == 66.65891299485574
+
+# export
+eval(Meta.parse(join(["export $x " for x in keys(exchange_rates)], ";")));

src/consts.jl

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+using EzXML
+using HTTP
+
+function get_xml(; url="https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml")
+    @info "Fetching rates from $url"
+    r1 = HTTP.get(url, ["Accept" => "application/xml"];status_exception=false) 
+    r2 = String(r1.body)
+    r2
+end
+
+function get_rates_dict(; url="https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml")
+    s1 = get_xml(url=url)
+    x1 = EzXML.parsexml(s1)
+    d1 = x1.root
+    d = Dict("EUR" => 1.0)
+    for e in elements(elements(elements(d1)[3])[1])
+        d[e["currency"]] = parse(Float64,e["rate"])
+    end
+    d["€"] = d["EUR"]
+    d["£"] = d["GBP"]
+    d["¥"] = d["JYP"]
+    d
+end
+
+global exchange_rates = get_rates_dict()
+
+function fromto(from, to; exchange_rates = exchange_rates, url="https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml")
+    if !(typeof(exchange_rates) <: Dict)
+        exchange_rates = get_rates_dict(url=url)
+    end
+    exchange_rates[string(to)] / exchange_rates[string(from)]
+end
+