notes.txt

# Barcode Scanner with output
## Problem
  - We get a text input in the form of a barcode, with a carriage return
  - We want to output, elsewhere (not a return), the price associated with the barcode
  - Return nothing to the input event
  - Report Errors to the output, but not the input

## Questions
  - How do we define a valid barcode?
      -  For now, just have 10 or 13 digits and don't worry about check digit checking
  - Handle 'listening', or just build the bit that accepts an input
  - Handle 'output' to LCD, or send a string somewhere? 

## Examples
 '1234567890 Return' => '£12.99'
 '1234567980 Return' => '£11.50'
 '2234567980 Return' => '£10.00'

## Error conditions
 '12 Return' => 'Invalid Barcode'
 'Return' => 'Invalid Barcode'
 'Hello Return' => 'Invalid Barcode'
 '123456780 Return' => Can't find barcode => 'Invalid Barcode'
 '123456789 Return' => gets negative price => 'Invalid price in database'

## Data
### Input: String with carriage return
### Output: String, max line length 80, max lines 5
### Internal: Some sort of lookup for the barcode to translate to price. Hash for now? 
 { 'barcode' => 'price', 'barcode2' => 'price2' }
### Store price with or without symbol? As a string? If we store as a number we can do addition later etc. 

## Algorithm
Class initialized with barcode 
Error checking
Output via a handler, so output can vary
Outputs are strings