/// <summary>
/// Constructs automaton that accept strings representing the given integer. Surrounding
/// whitespace is permitted.
/// </summary>
/// <param name="value">The value string representation of integer.</param>
/// <returns></returns>
public static Automaton MakeIntegerValue(String value)
{
bool minus = false;
int i = 0;
while (i < value.Length)
{
char c = value[i];
if (c == '-')
{
minus = true;
}
if (c >= '1' && c <= '9')
{
break;
}
i++;
}
var b = new StringBuilder();
b.Append(value.Substring(i));
if (b.Length == 0)
{
b.Append("0");
}
Automaton s = minus ? Automaton.MakeChar('-') : Automaton.MakeChar('+').Optional();
Automaton ws = Datatypes.WhitespaceAutomaton;
return(Automaton.Minimize(
ws.Concatenate(
s.Concatenate(Automaton.MakeChar('0').Repeat())
.Concatenate(Automaton.MakeString(b.ToString())))
.Concatenate(ws)));
}
/// <summary>
/// Constructs automaton that accept strings representing the given decimal number.
/// Surrounding whitespace is permitted.
/// </summary>
/// <param name="value">The value string representation of decimal number.</param>
/// <returns></returns>
public static Automaton MakeDecimalValue(String value)
{
bool minus = false;
int i = 0;
while (i < value.Length)
{
char c = value[i];
if (c == '-')
{
minus = true;
}
if ((c >= '1' && c <= '9') || c == '.')
{
break;
}
i++;
}
var b1 = new StringBuilder();
var b2 = new StringBuilder();
int p = value.IndexOf('.', i);
if (p == -1)
{
b1.Append(value.Substring(i));
}
else
{
b1.Append(value.Substring(i, p - i));
i = value.Length - 1;
while (i > p)
{
char c = value[i];
if (c >= '1' && c <= '9')
{
break;
}
i--;
}
b2.Append(value.Substring(p + 1, i + 1 - (p + 1)));
}
if (b1.Length == 0)
{
b1.Append("0");
}
Automaton s = minus ? Automaton.MakeChar('-') : Automaton.MakeChar('+').Optional();
Automaton d;
if (b2.Length == 0)
{
d = Automaton.MakeChar('.').Concatenate(Automaton.MakeChar('0').Repeat(1)).Optional();
}
else
{
d = Automaton.MakeChar('.')
.Concatenate(Automaton.MakeString(b2.ToString()))
.Concatenate(Automaton.MakeChar('0')
.Repeat());
}
Automaton ws = Datatypes.WhitespaceAutomaton;
return(Automaton.Minimize(
ws.Concatenate(
s.Concatenate(Automaton.MakeChar('0').Repeat())
.Concatenate(Automaton.MakeString(b1.ToString()))
.Concatenate(d))
.Concatenate(ws)));
}
