/// <summary>
/// This level of abstraction of an expression includes logical expressions.
/// Called everywhere where a logical or normal expression can be expected to be.
/// </summary>
void EXP_L()
{
EXP_R();
while (la.kind == 35) // "and"
{
Get();
QuadrupleManager.PushOperator(SemanticCubeUtilities.Operators.and);
EXP_R();
try { QuadrupleManager.PopOperator(SemanticCubeUtilities.OperatorToPriority(SemanticCubeUtilities.Operators.and)); }
catch (Exception e) { SemErr(e.Message); }
}
}
/// <summary>
/// The highest abstraction level for an expression. This type of expression includes
/// logical and relational operations.
/// This function is called everywhere where any type of expression can be expected to be.
/// </summary>
void SUPER_EXP()
{
EXP_L();
while (la.kind == 34) // or
{
Get();
QuadrupleManager.PushOperator(SemanticCubeUtilities.Operators.or);
EXP_L();
try { QuadrupleManager.PopOperator(SemanticCubeUtilities.OperatorToPriority(SemanticCubeUtilities.Operators.or)); }
catch (Exception e) { SemErr(e.Message); }
}
}
/// <summary>
/// This level of abstraction of an expression includes relational expressions.
/// Called everywhere where a relational or normal expression can be expected to be.
/// </summary>
void EXP_R()
{
EXP();
if (StartOf(5))
{
OP();
SemanticCubeUtilities.Operators op = SemanticCubeUtilities.GetOperatorFromString(t.val);
QuadrupleManager.PushOperator(op);
EXP();
try { QuadrupleManager.PopOperator(SemanticCubeUtilities.OperatorToPriority(op)); }
catch (Exception e) { SemErr(e.Message); }
}
}
/// <summary>
/// Calls <see cref="FACTOR"/> and checks whether a multiplication or division is pending and
/// if the next token is a multiplication or division.
/// Called by <see cref="EXP"/>.
/// </summary>
void TERM()
{
FACTOR();
try { QuadrupleManager.PopOperator(SemanticCubeUtilities.OperatorToPriority(SemanticCubeUtilities.Operators.multiply)); }
catch (Exception e) { SemErr(e.Message); }
while (la.kind == 38 || la.kind == 39) // '*' or '/'
{
if (la.kind == 38) // '*'
{
Get();
QuadrupleManager.PushOperator(SemanticCubeUtilities.Operators.multiply);
}
else // '/'
{
Get();
QuadrupleManager.PushOperator(SemanticCubeUtilities.Operators.divide);
}
FACTOR();
try { QuadrupleManager.PopOperator(SemanticCubeUtilities.OperatorToPriority(SemanticCubeUtilities.Operators.multiply)); }
catch (Exception e) { SemErr(e.Message); }
}
}
/// <summary>
/// Function called when an expression is found.
/// Checks for pending addition or substraction operations, and checks if the next
/// token is an addition or substraction.
/// </summary>
void EXP()
{
TERM();
try { QuadrupleManager.PopOperator(SemanticCubeUtilities.OperatorToPriority(SemanticCubeUtilities.Operators.plus)); }
catch (Exception e) { SemErr(e.Message); }
while (la.kind == 36 || la.kind == 37) // '+' or '-'
{
if (la.kind == 36) // '+'
{
Get();
QuadrupleManager.PushOperator(SemanticCubeUtilities.Operators.plus);
}
else // '-'
{
Get();
QuadrupleManager.PushOperator(SemanticCubeUtilities.Operators.minus);
}
TERM();
try { QuadrupleManager.PopOperator(SemanticCubeUtilities.OperatorToPriority(SemanticCubeUtilities.Operators.plus)); }
catch (Exception e) { SemErr(e.Message); }
}
}
/// <summary>
/// This is the lowest level of abstraction for an expression. Checks which is the
/// factor being used as an expression, retrieves this information, and calls the
/// necessesary functions in <see cref="QuadrupleManager"/> that handles each case
/// individually.
/// Called by <see cref="TERM"/>.
/// </summary>
void FACTOR()
{
if (la.kind == 10) // '('
// push a fake bottom
{
QuadrupleManager.PushFakeBottom();
Get();
SUPER_EXP();
Expect(12); // ')'
// exit fake bottom
QuadrupleManager.PopFakeBottom();
}
else if (StartOf(6))
{
if (la.kind == 37) // negative sign
{
Get();
QuadrupleManager.PushOperator(SemanticCubeUtilities.Operators.negative);
}
if (la.kind == 4) // number constant
{
Get();
try { QuadrupleManager.ReadConstantNumber(Int32.Parse(t.val)); }
catch (Exception e) { SemErr(e.Message); }
}
else if (la.kind == 1) // id
{
Get();
string id = t.val;
if (la.kind == 22) // '.' character
{
try
{
QuadrupleManager.ReadAssetId(id);
Get();
ATTRIBUTE(); // we don't need to verify the attribute as the UI forces the user to select a valid one
}
catch (Exception e) { SemErr(e.Message); }
}
else
{
try { QuadrupleManager.ReadIDVariable(id); }
catch (Exception e) { SemErr(e.Message); }
}
}
else if (la.kind == 19) // "call"
{
CALL_TO_FUNCTION();
}
else if (la.kind == 2 || la.kind == 3) // true or false
{
BOOL();
}
else if (la.kind == 5) // string constant
{
Get();
try { QuadrupleManager.ReadConstantText(t.val); }
catch (Exception e) { SemErr(e.Message); }
}
else
{
SynErr(60); // invalid FACTOR
}
try { QuadrupleManager.PopOperator(SemanticCubeUtilities.OperatorToPriority(SemanticCubeUtilities.Operators.negative)); }
catch (Exception e) { SemErr(e.Message); }
}
else
{
SynErr(61); // invalid FACTOR
}
}