| public static IsExpression ( string input ) : bool | ||
| input | string | |
| return | bool | |
static IEnumerable <string> PossibleInterpretationsHelper(string input, int depth)
{
yield return(input);
if (depth == 0)
{
yield break;
}
var chars = Enumerable.Range('a', 'z' - 'a' + 1).Select(k => (char)k).ToList();
//var chars = new FiniteEnumeration<char>(tmp);
Func <string, IEnumerable <string> > insert = str =>
{
var positions = Enumerable.Range(0, str.Length).Where(k => Char.IsLetterOrDigit(str[k]));
var strs = from pos in positions
from c in chars
from b in new[] { true, false }
let edit = b ? Char.ToUpper(c) : c
let copy = str.Insert(pos, edit.ToString())
where copy != input
select copy;
return(strs);
};
Func <string, IEnumerable <string> > delete = str =>
{
var strs = from pos in Enumerable.Range(0, str.Length)
where Char.IsLetterOrDigit(str[pos])
let copy = str.Remove(pos, 1)
where copy != input
select copy;
return(strs);
};
Func <string, IEnumerable <string> > substitute = str =>
{
var positions = Enumerable.Range(0, str.Length).Where(k => Char.IsLetterOrDigit(str[k]));
var strs = from pos in positions
from c in chars
from b in new[] { true, false }
let edit = b ? Char.ToUpper(c) : c
let copy = str.Remove(pos, 1).Insert(pos, edit.ToString())
where copy != input
select copy;
return(strs);
};
Func <string, int, bool> IsGreedy = (str, starpos) =>
{
if (starpos + 1 == str.Length)
{
return(true); // last position is not a ?
}
if (str[starpos + 1] == '?')
{
return(false); // found a *? so this is a nongreedy match
}
return(true); // just a star in isolation
};
Func <string, IEnumerable <string> > makenongreedy = str =>
{
var starpos = str.Select((k, i) => Tuple.Create(k, i)).Where(i => i.Item1 == '*').Select(i => i.Item2).Where(k => IsGreedy(str, k)).ToList();
var strs = from pos in starpos
//where IsGreedy(str, pos) == true
let copy = str.Remove(pos, 1).Insert(pos, "*?")
where copy != input
select copy;
return(strs);
};
Func <string, IEnumerable <string> > makegreedy = str =>
{
var starpos = str.Select((k, i) => Tuple.Create(k, i)).Where(i => i.Item1 == '*').Select(i => i.Item2).Where(k => !IsGreedy(str, k)).ToList();
var strs = from pos in starpos
//where IsGreedy(str, pos) == false
let copy = str.Remove(pos, 2).Insert(pos, "*")
where copy != input
select copy;
return(strs);
};
var edits = new[] { insert, delete, substitute, makenongreedy, makegreedy };
var output = from edit in edits
from editedinput in edit(input)
where Parser.IsExpression(editedinput)
select editedinput;
var recurse = from edit in output
from next in PossibleInterpretationsHelper(edit, depth - 1)
select next;
foreach (var item in recurse)
{
yield return(item);
}
}
static Uncertain <string> PossibleInterpretations2(string input)
{
var tmp = Enumerable.Range('a', 'z' - 'a' + 1).Select(k => (char)k).ToList();
var chars = new Multinomial <char>(tmp);
Func <string, Uncertain <string> > insert = str =>
{
var positions = Enumerable.Range(0, str.Length).Where(k => Char.IsLetterOrDigit(str[k]));
if (positions.Count() == 0)
{
return(String.Empty);
}
var strs = from pos in new Multinomial <int>(positions.ToList())
from c in chars
from b in new Flip(0.5)
let edit = b ? Char.ToUpper(c) : c
let copy = str.Insert(pos, edit.ToString())
where copy != input
select copy;
return(strs);
};
Func <string, Uncertain <string> > delete = str =>
{
var positions = Enumerable.Range(0, str.Length).Where(k => Char.IsLetterOrDigit(str[k]));
if (positions.Count() == 0)
{
return(String.Empty);
}
var strs = from pos in new Multinomial <int>(positions.ToList())
let copy = str.Remove(pos, 1)
where copy != input
select copy;
return(strs);
};
Func <string, Uncertain <string> > substitute = str =>
{
var positions = Enumerable.Range(0, str.Length).Where(k => Char.IsLetterOrDigit(str[k]));
if (positions.Count() == 0)
{
return(String.Empty);
}
var strs = from pos in new Multinomial <int>(positions.ToList())
from c in chars
from b in new Flip(0.5)
let edit = b ? Char.ToUpper(c) : c
let copy = str.Remove(pos, 1).Insert(pos, edit.ToString())
where copy != input
select copy;
return(strs);
};
Func <string, int, bool> IsGreedy = (str, starpos) =>
{
if (starpos + 1 == str.Length)
{
return(true); // last position is not a ?
}
if (str[starpos + 1] == '?')
{
return(false); // found a *? so this is a nongreedy match
}
return(true); // just a star in isolation
};
Func <string, Uncertain <string> > makenongreedy = str =>
{
var starpos = str.Select((k, i) => Tuple.Create(k, i)).Where(i => i.Item1 == '*').Select(i => i.Item2).Where(k => IsGreedy(str, k)).ToList();
if (starpos.Count == 0)
{
return(String.Empty);
}
var strs = from pos in new Multinomial <int>(starpos)
let copy = str.Remove(pos, 1).Insert(pos, "*?")
where copy != input
select copy;
return(strs);
};
Func <string, Uncertain <string> > makegreedy = str =>
{
var starpos = str.Select((k, i) => Tuple.Create(k, i)).Where(i => i.Item1 == '*').Select(i => i.Item2).Where(k => !IsGreedy(str, k)).ToList();
if (starpos.Count == 0)
{
return(String.Empty);
}
var strs = from pos in new Multinomial <int>(starpos)
let copy = str.Remove(pos, 2).Insert(pos, "*")
where copy != input
select copy;
return(strs);
};
var edits = new Multinomial <Func <string, Uncertain <string> > >(new[] { insert, delete, substitute, makenongreedy, makegreedy });
var output = from edit in edits
from editedinput in edit(input)
where editedinput != String.Empty && Parser.IsExpression(editedinput)
select editedinput;
var recurse = from edit in output
from b in new Flip(0.1)
let next = b ? PossibleInterpretations2(edit) : edit
from recursivelyedited in next
select recursivelyedited;
return(recurse);
}