ba-st / aconcagua

Measures as first class objects, that is, an object that encapsulates a number with its unit.

Aconcagua

This model represents measures as first class objects, that is, an object that encapsulates a number with its unit.

Named after Aconcagua, the highest mountain in both the southern and western hemispheres. It is located in the Andes, in the Mendoza Province, Argentina.

This representation allows the programmer to use measures in arithmetic expressions as if they were numbers, but with the advantage of providing explicit information to the system, specifically, the measures units. See Arithmetic with measurements on dynamically-typed object-oriented languages or download the article PDF for more about this.

Quick links

• Explore the docs
• Report a defect
• Request a feature

License

• The code is licensed under MIT.
• The documentation is licensed under CC BY-SA 4.0.

Quick Start

• Download the latest Pharo 32 or 64 bits VM.
• Download a ready to use image from the release page
• Explore the documentation

Installation

To load the project in a Pharo image, or declare it as a dependency of your own project follow these instructions.

Contributing

Check the Contribution Guidelines

aconcagua's Issues

CircularReadStream class doesn't have references

It's been used in Chalten but not it Aconcagua. The implementation seems coupled with measures, maybe there is room for enhancement.

Typo in BaseUnit>>initializeNameFomOne:nameForMany:sign:

Should be named initializeNameForOne:nameForMany:sign:

Converting MeasureBag to Amount of Unit

I tried the following and got aMeasureBag back, but I expected 10.21

amount := 10.21.
dollarAmt := amount // 1.
centsAmt := (amount \\ 1 * 100) asInteger.
total := (AmDollar new * dollarAmt) +
(centsAmt * AmCent new).
total / (1 * AmDollar new).

Also I tried convertTo: but got a subclassResponsibility error...

where:

AmDollar class>>#new
	^ super new
		initializeBaseUnit: AmCent new
		conversionFactor: 100
		nameForOne: 'dollar'
		nameForMany: 'dollars'
		sign: 'USD'

and

AmCent class>>#new
	^ super new
		initializeNameFomOne: 'cent'
		nameForMany: 'cents'
		sign: 'c USD'

Money Documentation

I'd like to add some information to the docs about modeling money. This has come up many times on the MLs of the various Smalltalk flavors, and Aconcagua has been mentioned many times. However, even after reading and re-reading, I'm still not clear how Aconcagua addresses the float problem. Namely, by way of example:

result := 0.
interval := 10.21.
10000 timesRepeat: [ result := result + interval ].
result = 102100.00000001806 "(not 102100.0)"

At first, I thought that using ScaledDecimal might help, but there were various comments saying that Pharo's ScaledDecimal is ill-conceived and maybe FixedDecimal would be better.

Another solution I thought of would be to convert any decimal money to dollars and cents and only convert back for display. For example:

Float>>dollars
	^ (AmDollar uniqueInstance * self // 1) +
(self \\ 1 * 100) asInteger cents.

Any feedback or input would be appreciated...

@gcotelli @mtaborda @hernanwilkinson

Delete Evaluation hierarchy

Evaluation and its subclasses doesn't have references

#printMeasure:on: - should it be moved to `UnitBehavior`?

See discussion on #21

Add integration with travis and coveralls

Add .travis.yml and .smalltalk.ston to integrate the repository with Travis and Coveralls