evalengine

package
v0.12.0 Latest Latest
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 Go to latest Published: Oct 26, 2021 License: Apache-2.0 Imports: 10 Imported by: 1

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Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func Add 

func Add(v1, v2 sqltypes.Value) (sqltypes.Value, error)

Add adds two values together if v1 or v2 is null, then it returns null

func Cast 

func Cast(v sqltypes.Value, typ querypb.Type) (sqltypes.Value, error)

Cast converts a Value to the target type.

func Divide 

func Divide(v1, v2 sqltypes.Value) (sqltypes.Value, error)

Divide (Float) for MySQL. Replicates behavior of "/" operator

func Max 

func Max(v1, v2 sqltypes.Value) (sqltypes.Value, error)

Max returns the maximum of v1 and v2. If one of the values is NULL, it returns the other value. If both are NULL, it returns NULL.

func Min 

func Min(v1, v2 sqltypes.Value) (sqltypes.Value, error)

Min returns the minimum of v1 and v2. If one of the values is NULL, it returns the other value. If both are NULL, it returns NULL.

func Multiply 

func Multiply(v1, v2 sqltypes.Value) (sqltypes.Value, error)

Multiply takes two values and multiplies it together

func NullsafeAdd 

func NullsafeAdd(v1, v2 sqltypes.Value, resultType querypb.Type) sqltypes.Value

NullsafeAdd adds two Values in a null-safe manner. A null value is treated as 0. If both values are null, then a null is returned. If both values are not null, a numeric value is built from each input: Signed->int64, Unsigned->uint64, Float->float64. Otherwise the 'best type fit' is chosen for the number: int64 or float64. Addition is performed by upgrading types as needed, or in case of overflow: int64->uint64, int64->float64, uint64->float64. Unsigned ints can only be added to positive ints. After the addition, if one of the input types was Decimal, then a Decimal is built. Otherwise, the final type of the result is preserved.

func NullsafeCompare 

func NullsafeCompare(v1, v2 sqltypes.Value) (int, error)

NullsafeCompare returns 0 if v1==v2, -1 if v1<v2, and 1 if v1>v2. NULL is the lowest value. If any value is numeric, then a numeric comparison is performed after necessary conversions. If none are numeric, then it's a simple binary comparison. Uncomparable values return an error.

func NullsafeHashcode added in v0.9.0 

func NullsafeHashcode(v sqltypes.Value) (int64, error)

NullsafeHashcode returns an int64 hashcode that is guaranteed to be the same for two values that are considered equal by `NullsafeCompare`. TODO: should be extended to support all possible types

func Subtract 

func Subtract(v1, v2 sqltypes.Value) (sqltypes.Value, error)

Subtract takes two values and subtracts them

func ToFloat64 

func ToFloat64(v sqltypes.Value) (float64, error)

ToFloat64 converts Value to float64.

func ToInt64 

func ToInt64(v sqltypes.Value) (int64, error)

ToInt64 converts Value to int64.

func ToNative 

func ToNative(v sqltypes.Value) (interface{}, error)

ToNative converts Value to a native go type. Decimal is returned as []byte.

func ToUint64 

func ToUint64(v sqltypes.Value) (uint64, error)

ToUint64 converts Value to uint64.

Types

type Addition 

type Addition struct{}

Binary ops

func (*Addition) Evaluate 

func (a *Addition) Evaluate(left, right EvalResult) (EvalResult, error)

Evaluate implements the BinaryOp interface

func (*Addition) String 

func (a *Addition) String() string

String implements the BinaryExpr interface

func (*Addition) Type 

func (a *Addition) Type(left querypb.Type) querypb.Type

Type implements the BinaryExpr interface

type BinaryExpr 

type BinaryExpr interface {
	Evaluate(left, right EvalResult) (EvalResult, error)
	Type(left querypb.Type) querypb.Type
	String() string
}

BinaryExpr allows binary expressions to not have to evaluate child expressions - this is done by the BinaryOp

type BinaryOp 

type BinaryOp struct {
	Expr        BinaryExpr
	Left, Right Expr
}

func (*BinaryOp) CachedSize added in v0.10.0 

func (cached *BinaryOp) CachedSize(alloc bool) int64

func (*BinaryOp) Evaluate 

func (b *BinaryOp) Evaluate(env ExpressionEnv) (EvalResult, error)

Evaluate implements the Expr interface

func (*BinaryOp) String 

func (b *BinaryOp) String() string

String implements the Expr interface

func (*BinaryOp) Type 

func (b *BinaryOp) Type(env ExpressionEnv) (querypb.Type, error)

Type implements the Expr interface

type BindVariable 

type BindVariable struct{ Key string }

func (*BindVariable) CachedSize added in v0.10.0 

func (cached *BindVariable) CachedSize(alloc bool) int64

func (*BindVariable) Evaluate 

func (b *BindVariable) Evaluate(env ExpressionEnv) (EvalResult, error)

Evaluate implements the Expr interface

func (*BindVariable) String 

func (b *BindVariable) String() string

String implements the Expr interface

func (*BindVariable) Type 

func (b *BindVariable) Type(env ExpressionEnv) (querypb.Type, error)

Type implements the Expr interface

type Column 

type Column struct{ Offset int }

func (*Column) CachedSize added in v0.10.0 

func (cached *Column) CachedSize(alloc bool) int64

func (*Column) Evaluate 

func (c *Column) Evaluate(env ExpressionEnv) (EvalResult, error)

Evaluate implements the Expr interface

func (*Column) String 

func (c *Column) String() string

String implements the Expr interface

func (*Column) Type 

func (c *Column) Type(ExpressionEnv) (querypb.Type, error)

Type implements the Expr interface

type Division 

type Division struct{}

func (*Division) Evaluate 

func (d *Division) Evaluate(left, right EvalResult) (EvalResult, error)

Evaluate implements the BinaryOp interface

func (*Division) String 

func (d *Division) String() string

String implements the BinaryExpr interface

func (*Division) Type 

func (d *Division) Type(querypb.Type) querypb.Type

Type implements the BinaryExpr interface

type EvalResult 

type EvalResult struct {
	// contains filtered or unexported fields
}

func (*EvalResult) CachedSize added in v0.10.0 

func (cached *EvalResult) CachedSize(alloc bool) int64

func (*EvalResult) ToBooleanStrict added in v0.8.0 

func (e *EvalResult) ToBooleanStrict() (bool, error)

ToBooleanStrict is used when the casting to a boolean has to be minimally forgiving, such as when assigning to a system variable that is expected to be a boolean

func (EvalResult) Value 

func (e EvalResult) Value() sqltypes.Value

Value allows for retrieval of the value we expose for public consumption

type Expr 

type Expr interface {
	Evaluate(env ExpressionEnv) (EvalResult, error)
	Type(env ExpressionEnv) (querypb.Type, error)
	String() string
}

Expr is the interface that all evaluating expressions must implement

func NewBindVar added in v0.8.0 

func NewBindVar(key string) Expr

NewBindVar returns a bind variable

func NewColumn added in v0.8.0 

func NewColumn(offset int) Expr

NewColumn returns a bind variable

func NewLiteralFloat 

func NewLiteralFloat(val []byte) (Expr, error)

NewLiteralFloat returns a literal expression

func NewLiteralInt 

func NewLiteralInt(i int64) Expr

NewLiteralInt returns a literal expression

func NewLiteralIntFromBytes added in v0.8.0 

func NewLiteralIntFromBytes(val []byte) (Expr, error)

NewLiteralIntFromBytes returns a literal expression

func NewLiteralString 

func NewLiteralString(val []byte) Expr

NewLiteralFloat returns a literal expression

type ExpressionEnv 

type ExpressionEnv struct {
	BindVars map[string]*querypb.BindVariable
	Row      []sqltypes.Value
}

ExpressionEnv contains the environment that the expression evaluates in, such as the current row and bindvars

type Literal 

type Literal struct{ Val EvalResult }

Expressions

func (*Literal) CachedSize added in v0.10.0 

func (cached *Literal) CachedSize(alloc bool) int64

func (*Literal) Evaluate 

func (l *Literal) Evaluate(ExpressionEnv) (EvalResult, error)

Evaluate implements the Expr interface

func (*Literal) String 

func (l *Literal) String() string

String implements the Expr interface

func (*Literal) Type 

func (l *Literal) Type(ExpressionEnv) (querypb.Type, error)

Type implements the Expr interface

type Multiplication 

type Multiplication struct{}

func (*Multiplication) Evaluate 

func (m *Multiplication) Evaluate(left, right EvalResult) (EvalResult, error)

Evaluate implements the BinaryOp interface

func (*Multiplication) String 

func (m *Multiplication) String() string

String implements the BinaryExpr interface

func (*Multiplication) Type 

func (m *Multiplication) Type(left querypb.Type) querypb.Type

Type implements the BinaryExpr interface

type Subtraction 

type Subtraction struct{}

func (*Subtraction) Evaluate 

func (s *Subtraction) Evaluate(left, right EvalResult) (EvalResult, error)

Evaluate implements the BinaryOp interface

func (*Subtraction) String 

func (s *Subtraction) String() string

String implements the BinaryExpr interface

func (*Subtraction) Type 

func (s *Subtraction) Type(left querypb.Type) querypb.Type

Type implements the BinaryExpr interface

type UnsupportedComparisonError added in v0.10.0 

type UnsupportedComparisonError struct {
	Type1 querypb.Type
	Type2 querypb.Type
}

UnsupportedComparisonError represents the error where the comparison between the two types is unsupported on vitess

func (UnsupportedComparisonError) Error added in v0.10.0 

func (err UnsupportedComparisonError) Error() string

Error function implements the error interface

Source Files

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