public void Or_FirstSuccess_ReturnsFirstResult()
{
var parser = Combine.Or(Parse.Succeed('x'), Parse.Succeed('y'));
var result = parser.Parse("");
ParseAssert.ValueEquals('x', result);
}
public void Or_FirstError_ReturnsSecondResult()
{
var parser = Combine.Or(Parse.Fail <int>("test"), Parse.Succeed(42));
var result = parser.Parse("");
ParseAssert.ValueEquals(42, result);
}
public void Succeed_ReturnsGivenValue()
{
var parser = Parse.Succeed('x');
var result = parser.Parse("");
ParseAssert.ValueEquals('x', result);
}
public void Label_Success_ReturnsSuccess()
{
var parser = Parse.Succeed(42).Label(() => "test");
var result = parser.Parse("");
ParseAssert.ValueEquals(42, result);
}
public void Many_IEnumerable()
{
var parser = (from c in Chars.Any()
from x in Parse.Succeed(42)
select x).Many();
var result = parser.Parse("xyz");
ParseAssert.ValueEquals(new[] { 42, 42, 42 }, result);
}
/// <summary>
/// Repeats a parser a given number of times.
/// </summary>
public static IParser <IEnumerable <TValue> > Repeat <TValue>(this IParser <TValue> parser, int repeatCount)
{
if (repeatCount <= 0)
{
return(Parse.Succeed(Enumerable.Empty <TValue>()));
}
return(Parse.Sequence(Enumerable.Repeat(parser, repeatCount)));
}
public void Select_Success_ReturnsSelectedValue()
{
var parser = from i in Parse.Succeed(21)
select i * 2;
var result = parser.Parse("");
ParseAssert.ValueEquals(42, result);
}
public void Try_Success_ReturnsSuccess()
{
var parser = from a in Parse.Try(Parse.Succeed("a"))
from b in Parse.Try(Parse.Succeed("b"))
select a + b;
var result = parser.Parse("abc");
ParseAssert.ValueEquals("ab", result);
}
public void Where_PassingPredicate_ReturnsSuccess()
{
var parser = from x in Parse.Succeed(42)
where x == 42
select x;
var result = parser.Parse("");
ParseAssert.ValueEquals(42, result);
}
public void SelectMany_SuccessThenError_ReturnsErrorValue()
{
var parser = from x in Parse.Succeed(21)
from y in Parse.Fail <int>("test")
select x *y;
var result = parser.Parse("");
ParseAssert.ErrorEquals("test", result);
}
public void SelectMany_Successes_ReturnsSelectedValue()
{
var parser = from x in Parse.Succeed(21)
from y in Parse.Succeed(2)
select x *y;
var result = parser.Parse("");
ParseAssert.ValueEquals(42, result);
}
public void Where_FailingPredicate_ReturnsError()
{
var parser = from x in Parse.Succeed(42)
where x != 42
select x;
var result = parser.Parse("");
ParseAssert.ErrorEquals("Unexpected \"42\"", result);
}
public void SelectMany_ManySuccesses_CombinesAll()
{
var parser = from w in Parse.Succeed(21)
from x in Parse.Succeed(3)
from y in Parse.Succeed(4)
from z in Parse.Succeed(6)
select(w * x * y) / z;
var result = parser.Parse("");
ParseAssert.ValueEquals(42, result);
}
/// <summary>
/// Parses zero or more occurrences of a parser, each followed by a separator parser.
/// </summary>
public static IParser <IEnumerable <T> > SeparatedBy <T, TSep>(this IParser <T> parser, IParser <TSep> separator)
{
return(SeparatedBy1(parser, separator).Or(Parse.Succeed(Enumerable.Empty <T>())));
}
