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Error reporting improvement for number operations; added power operator

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This commit is contained in:
Robert Bendun 2022-09-04 19:44:33 +02:00
parent 497a4bcc6a
commit de92564cc1
5 changed files with 137 additions and 43 deletions
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23
include/musique.hh
View File

@ -184,6 +184,16 @@ namespace errors
} type;
};
struct Arithmetic
{
enum Type
{
Division_By_Zero,
Fractional_Modulo,
Unable_To_Calculate_Modular_Multiplicative_Inverse
} type;
};
/// Collection of messages that are considered internal and should not be printed to the end user.
namespace internal
{
@ -203,6 +213,7 @@ namespace errors
/// All possible error types
using Details = std::variant<
Arithmetic,
Closing_Token_Without_Opening,
Expected_Expression_Separator_Before,
Failed_Numeric_Parsing,
@ -456,7 +467,7 @@ struct Token
};
static constexpr usize Keywords_Count = 6;
static constexpr usize Operators_Count = 15;
static constexpr usize Operators_Count = 16;
std::string_view type_name(Token::Type type);
@ -703,17 +714,15 @@ struct Number
Number& operator-=(Number const& rhs);
Number operator*(Number const& rhs) const;
Number& operator*=(Number const& rhs);
Number operator/(Number const& rhs) const;
Number& operator/=(Number const& rhs);
Number operator%(Number const& rhs) const;
Number& operator%=(Number const& rhs);
Result<Number> operator/(Number const& rhs) const;
Result<Number> operator%(Number const& rhs) const;
Number floor() const; ///< Return number rounded down to nearest integer
Number ceil() const; ///< Return number rounded up to nearest integer
Number round() const; ///< Return number rounded to nearest integer
Number inverse() const; ///< Return number raised to power -1
Number pow(Number n) const; ///< Return number raised to power `n`.
Result<Number> inverse() const; ///< Return number raised to power -1
Result<Number> pow(Number n) const; ///< Return number raised to power `n`.
/// Parses source contained by token into a Number instance
static Result<Number> from(Token token);

14
src/builtin_operators.cc
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@ -87,7 +87,6 @@ static Result<Value> plus_minus_operator(Interpreter &interpreter, std::vector<V
};
}
template<typename Binary_Operation, char ...Chars>
static Result<Value> binary_operator(Interpreter& interpreter, std::vector<Value> args)
{
@ -97,8 +96,12 @@ static Result<Value> binary_operator(Interpreter& interpreter, std::vector<Value
if (NN::typecheck(args)) {
auto [lhs, rhs] = NN::move_from(args);
if constexpr (is_template_v<Result, decltype(Binary_Operation{}(lhs, rhs))>) {
return Value::from(Try(Binary_Operation{}(lhs, rhs)));
} else {
return Value::from(Binary_Operation{}(lhs, rhs));
}
}
if (may_be_vectorized(args)) {
return vectorize(binary_operator<Binary_Operation, Chars...>, interpreter, args);
@ -182,6 +185,14 @@ static Result<Value> multiplication_operator(Interpreter &i, std::vector<Value>
using Operator_Entry = std::tuple<char const*, Intrinsic>;
struct pow_operator
{
inline Result<Number> operator()(Number lhs, Number rhs)
{
return lhs.pow(rhs);
}
};
/// Operators definition table
static constexpr auto Operators = std::array {
Operator_Entry { "+", plus_minus_operator<std::plus<>> },
@ -189,6 +200,7 @@ static constexpr auto Operators = std::array {
Operator_Entry { "*", multiplication_operator },
Operator_Entry { "/", binary_operator<std::divides<>, '/'> },
Operator_Entry { "%", binary_operator<std::modulus<>, '%'> },
Operator_Entry { "**", binary_operator<pow_operator, '*', '*'> },
Operator_Entry { "<", comparison_operator<std::less<>> },
Operator_Entry { ">", comparison_operator<std::greater<>> },

35
src/errors.cc
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@ -146,6 +146,15 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
[](errors::Expected_Expression_Separator_Before const&) { return "Missing semicolon"; },
[](errors::Literal_As_Identifier const&) { return "Literal used in place of an identifier"; },
[](errors::Out_Of_Range const&) { return "Index out of range"; },
[](errors::Arithmetic const& err) {
switch (err.type) {
case errors::Arithmetic::Division_By_Zero: return "Division by 0";
case errors::Arithmetic::Fractional_Modulo: return "Modulo with fractions";
case errors::Arithmetic::Unable_To_Calculate_Modular_Multiplicative_Inverse:
return "Missing modular inverse";
default: unreachable();
}
},
[](errors::Closing_Token_Without_Opening const& err) {
return err.type == errors::Closing_Token_Without_Opening::Block
? "Block closing without opening"
@ -368,6 +377,32 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
print_error_line(loc);
},
[&](errors::Arithmetic const& err) {
switch (err.type) {
break; case errors::Arithmetic::Division_By_Zero:
os << "Tried to divide by 0 which is undefined operation in math\n";
os << "\n";
print_error_line(loc);
break; case errors::Arithmetic::Fractional_Modulo:
os << "Tried to calculate modulo with fractional modulus which is not defined\n";
os << "\n";
print_error_line(loc);
os << pretty::begin_comment;
os << "Example code that could raise this error:\n";
os << " 1 % (1/2)\n";
os << pretty::end;
break; case errors::Arithmetic::Unable_To_Calculate_Modular_Multiplicative_Inverse:
os << "Tried to calculate fraction in modular space.\n";
os << "\n";
print_error_line(loc);
}
},
[&](errors::Unexpected_Keyword const&) { unimplemented(); },
}, err.details);

87
src/number.cc
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@ -106,37 +106,72 @@ Number& Number::operator*=(Number const& rhs)
return *this;
}
Number Number::operator/(Number const& rhs) const
Result<Number> Number::operator/(Number const& rhs) const
{
if (rhs.num == 0) {
return Error {
.details = errors::Arithmetic {
.type = errors::Arithmetic::Division_By_Zero
}
};
}
return Number{num * rhs.den, den * rhs.num}.simplify();
}
Number& Number::operator/=(Number const& rhs)
inline auto modular_inverse(Number::value_type a, Number::value_type n)
-> Result<Number::value_type>
{
num *= rhs.den;
den *= rhs.num;
simplify_inplace();
return *this;
using N = Number::value_type;
N t = 0, newt = 1;
N r = n, newr = a;
while (newr != 0) {
auto q = r / newr;
t = std::exchange(newt, t - q * newt);
r = std::exchange(newr, r - q * newr);
}
if (r > 1) {
return Error {
.details = errors::Arithmetic {
.type = errors::Arithmetic::Unable_To_Calculate_Modular_Multiplicative_Inverse
}
};
}
return t < 0 ? t + n : t;
}
Number Number::operator%(Number const& rhs) const
Result<Number> Number::operator%(Number const& rhs) const
{
return Number(*this) %= rhs;
if (rhs.num == 0) {
return Error {
.details = errors::Arithmetic {
.type = errors::Arithmetic::Division_By_Zero
}
};
}
Number& Number::operator%=(Number const& rhs)
{
simplify_inplace();
auto ret = simplify();
auto [rnum, rden] = rhs.simplify();
if (den == 1 && rden == 1) {
num %= rnum;
} else {
assert(false, "Modulo for fractions is not supported");
if (rden != 1) {
return Error {
.details = errors::Arithmetic {
.type = errors::Arithmetic::Fractional_Modulo
}
};
}
return *this;
if (ret.den == 1) {
ret.num %= rnum;
return ret;
}
return Number(
(Try(modular_inverse(ret.den, rnum)) * ret.num) % rnum
);
}
std::ostream& operator<<(std::ostream& os, Number const& n)
@ -252,16 +287,22 @@ Number Number::round() const
return impl::round(*this, impl::Rounding_Mode::Round);
}
Number Number::inverse() const
Result<Number> Number::inverse() const
{
assert(num != 0, "Cannot take inverse of fraction with 0 in denominator");
if (num == 0) {
return Error {
.details = errors::Arithmetic {
.type = errors::Arithmetic::Division_By_Zero
}
};
}
return { den, num };
}
namespace impl
{
// Raise Number to integer power helper
static inline Number pow(Number const& x, decltype(Number::num) n)
static inline Result<Number> pow(Number const& x, decltype(Number::num) n)
{
// We simply raise numerator and denominator to required power
// and if n is negative we take inverse.
@ -273,11 +314,11 @@ namespace impl
for (auto i = n; i != 0; --i) result.num *= x.num;
for (auto i = n; i != 0; --i) result.den *= x.den;
return flip ? result.inverse() : result;
return flip ? Try(result.inverse()) : result;
}
}
Number Number::pow(Number n) const
Result<Number> Number::pow(Number n) const
{
n.simplify_inplace();
@ -289,9 +330,5 @@ Number Number::pow(Number n) const
// Hard case, we raise this to fractional power.
// Essentialy finding n.den root of (x to n.num power).
// We need to protect ourselfs against even roots of negative numbers.
// TODO Implement this case properly.
//
// TODO(assert) <- taking power is not always doable so this operation
// should produce error not crash with assertion failure in the future.
unimplemented();
}

3
src/parser.cc
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@ -519,13 +519,14 @@ static usize precedense(std::string_view op)
// '.' since it have own precedense rules and is not binary expression but its own kind of expression
//
// Exclusion of them is marked by subtracting total number of excluded operators.
static_assert(Operators_Count - 1 == 14, "Ensure that all operators have defined precedense below");
static_assert(Operators_Count - 1 == 15, "Ensure that all operators have defined precedense below");
if (one_of(op, "or")) return 100;
if (one_of(op, "and")) return 150;
if (one_of(op, "<", ">", "<=", ">=", "==", "!=")) return 200;
if (one_of(op, "+", "-")) return 300;
if (one_of(op, "*", "/", "%", "&")) return 400;
if (one_of(op, "**")) return 500;
unreachable();
}