import "go/constant"
Package constant implements Values representing untyped Go constants and their corresponding operations.
A special Unknown value may be used when a value is unknown due to an error. Operations on unknown values produce unknown values unless specified otherwise.
BitLen returns the number of bits required to represent the absolute value x in binary representation; x must be an Int or an Unknown. If x is Unknown, the result is 0.
BoolVal returns the Go boolean value of x, which must be a Bool or an Unknown. If x is Unknown, the result is false.
Bytes returns the bytes for the absolute value of x in little- endian binary representation; x must be an Int.
Compare returns the result of the comparison x op y. The comparison must be defined for the operands. If one of the operands is Unknown, the result is false.
Float32Val is like Float64Val but for float32 instead of float64.
Float64Val returns the nearest Go float64 value of x and whether the result is exact; x must be numeric or an Unknown, but not Complex. For values too small (too close to 0) to represent as float64, Float64Val silently underflows to 0. The result sign always matches the sign of x, even for 0. If x is Unknown, the result is (0, false).
Int64Val returns the Go int64 value of x and whether the result is exact; x must be an Int or an Unknown. If the result is not exact, its value is undefined. If x is Unknown, the result is (0, false).
Sign returns -1, 0, or 1 depending on whether x < 0, x == 0, or x > 0; x must be numeric or Unknown. For complex values x, the sign is 0 if x == 0, otherwise it is != 0. If x is Unknown, the result is 1.
StringVal returns the Go string value of x, which must be a String or an Unknown. If x is Unknown, the result is "".
Uint64Val returns the Go uint64 value of x and whether the result is exact; x must be an Int or an Unknown. If the result is not exact, its value is undefined. If x is Unknown, the result is (0, false).
Kind specifies the kind of value represented by a Value.
const ( // unknown values Unknown Kind = iota // non-numeric values Bool String // numeric values Int Float Complex )
type Value interface { // Kind returns the value kind. Kind() Kind // String returns a short, quoted (human-readable) form of the value. // For numeric values, the result may be an approximation; // for String values the result may be a shortened string. // Use ExactString for a string representing a value exactly. String() string // ExactString returns an exact, quoted (human-readable) form of the value. // If the Value is of Kind String, use StringVal to obtain the unquoted string. ExactString() string // contains filtered or unexported methods }
A Value represents the value of a Go constant.
BinaryOp returns the result of the binary expression x op y. The operation must be defined for the operands. If one of the operands is Unknown, the result is Unknown. BinaryOp doesn't handle comparisons or shifts; use Compare or Shift instead.
To force integer division of Int operands, use op == token.QUO_ASSIGN instead of token.QUO; the result is guaranteed to be Int in this case. Division by zero leads to a run-time panic.
Denom returns the denominator of x; x must be Int, Float, or Unknown. If x is Unknown, or if it is too large or small to represent as a fraction, the result is Unknown. Otherwise the result is an Int >= 1.
Imag returns the imaginary part of x, which must be a numeric or unknown value. If x is Unknown, the result is Unknown.
MakeBool returns the Bool value for b.
MakeFloat64 returns the Float value for x. If x is not finite, the result is an Unknown.
MakeFromBytes returns the Int value given the bytes of its little-endian binary representation. An empty byte slice argument represents 0.
MakeFromLiteral returns the corresponding integer, floating-point, imaginary, character, or string value for a Go literal string. The tok value must be one of token.INT, token.FLOAT, token.IMAG, token.CHAR, or token.STRING. The final argument must be zero. If the literal string syntax is invalid, the result is an Unknown.
MakeImag returns the Complex value x*i; x must be Int, Float, or Unknown. If x is Unknown, the result is Unknown.
MakeInt64 returns the Int value for x.
MakeString returns the String value for s.
MakeUint64 returns the Int value for x.
MakeUnknown returns the Unknown value.
Num returns the numerator of x; x must be Int, Float, or Unknown. If x is Unknown, or if it is too large or small to represent as a fraction, the result is Unknown. Otherwise the result is an Int with the same sign as x.
Real returns the real part of x, which must be a numeric or unknown value. If x is Unknown, the result is Unknown.
Shift returns the result of the shift expression x op s with op == token.SHL or token.SHR (<< or >>). x must be an Int or an Unknown. If x is Unknown, the result is x.
ToComplex converts x to a Complex value if x is representable as a Complex. Otherwise it returns an Unknown.
ToFloat converts x to a Float value if x is representable as a Float. Otherwise it returns an Unknown.
ToInt converts x to an Int value if x is representable as an Int. Otherwise it returns an Unknown.
UnaryOp returns the result of the unary expression op y. The operation must be defined for the operand. If prec > 0 it specifies the ^ (xor) result size in bits. If y is Unknown, the result is Unknown.