A regular expression like /\s(foo|bar|baz)\s.*/
would match the following string:
football bartender bazooka baz to the end
^^^^^^^^^^^^^^^
Is it possible to make a Parsing Expression Grammar rules that would parse the string in a similar fashion, splitting it into a Head and Tail?
Result <- Head Tail
football bartender bazooka baz to the end
Head | Tail
CodePudding user response:
Yes, it's achievable using PEG. Here's an example using pegjs:
start = f:words space r:tail
{
return [f, r];
}
tail = f:"baz" space r:words
{
return r;
}
words = f:word r:(space word)*
{
return [f].concat(r).flat().filter(n => n);
}
word = !tail w:$([A-Za-z] )
{
return w;
}
space = " "
{
return;
}
Output:
[
[
"football",
"bartender",
"bazooka"
],
[
"to",
"the",
"end"
]
]