[Pharo-project] PetitParser puzzle

May 6, 2011

      I have a unit test for a parser of mine:

testLine
	self fail: 'Just a line.' rule: #lineBlank.            "passes"
	self parse: 'Just a line.' rule: #lineNonBlank.   "passes"
	self parse: 'Just a line.' rule: #line.                 "end of input
expected at 0"

Now the fun part:

line
	^ lineBlank / lineNonBlank

For reference, here are the rest of the involved rules:

blank
	^ #blank asParser

lineBlank
	^ blank star

lineNonBlank
	^ blank star , blank not , lineEnd negate plus

lineEnd
	^ (Character lf asParser)
		/ (Character cr asParser , Character lf asParser optional)

Insights ?

-- 
Damien Pollet
type less, do more [ | ] http://people.untyped.org/damien.pollet