Am 06.05.2011 um 13:59 schrieb Damien Pollet:

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

try line ^ lineNonBlank / lineBlank Norbert

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

Ok, next try. Am 06.05.2011 um 13:59 schrieb Damien Pollet:

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"

Here you test if the parser can consume all of the string. But it different to the situation if the parser succeeds. A star parser always succeeds. And the operator / only matches of the parser on the left side couldn't succeed. In the "line" case the lineBlank succeeds thus the right one is not tried. So no characters are consumed and the test fails because it does not parse. That was what first came to my mind but then I thought this might be just a hack to reverse the order of ther parser. But my initial mail was right. The more specific parser should go before to all matching parser. hope this helps, Norbert

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