expr

Documentation

Index

• type Expr
  • func Int(v int64) (p *Expr)
  • func Ref(t Term) (p *Expr)
  • func (self *Expr) Add(v *Expr) *Expr
  • func (self *Expr) And(v *Expr) *Expr
  • func (self *Expr) Div(v *Expr) *Expr
  • func (self *Expr) Evaluate() (int64, error)
  • func (self *Expr) Free()
  • func (self *Expr) Mod(v *Expr) *Expr
  • func (self *Expr) Mul(v *Expr) *Expr
  • func (self *Expr) Neg() *Expr
  • func (self *Expr) Not() *Expr
  • func (self *Expr) Or(v *Expr) *Expr
  • func (self *Expr) Pow(v *Expr) *Expr
  • func (self *Expr) Shl(v *Expr) *Expr
  • func (self *Expr) Shr(v *Expr) *Expr
  • func (self *Expr) Sub(v *Expr) *Expr
  • func (self *Expr) Xor(v *Expr) *Expr
• type Operator
  • func (self Operator) String() string
• type Parser
  • func (self *Parser) Parse(repo Repository) (*Expr, error)
  • func (self *Parser) SetSource(src string) *Parser
• type Repository
• type RuntimeError
  • func (self *RuntimeError) Error() string
• type SyntaxError
  • func (self *SyntaxError) Error() string
• type Term
• type Type
  • func (self Type) String() string

Types

type Expr

type Expr struct {
	Type  Type
	Term  Term
	Op    Operator
	Left  *Expr
	Right *Expr
	Const int64
}

Expr represents an expression node.

func Int

func Int(v int64) (p *Expr)

Int creates an expression from an integer.

func Ref

func Ref(t Term) (p *Expr)

Ref creates an expression from a Term.

func (*Expr) Add

func (self *Expr) Add(v *Expr) *Expr

func (*Expr) And

func (self *Expr) And(v *Expr) *Expr

func (*Expr) Div

func (self *Expr) Div(v *Expr) *Expr

func (*Expr) Evaluate

func (self *Expr) Evaluate() (int64, error)

Evaluate evaluates the expression into an integer. It also implements the Term interface.

func (*Expr) Free

func (self *Expr) Free()

Free returns the Expr into pool. Any operation performed after Free is undefined behavior.

func (*Expr) Mod

func (self *Expr) Mod(v *Expr) *Expr

func (*Expr) Mul

func (self *Expr) Mul(v *Expr) *Expr

func (*Expr) Neg

func (self *Expr) Neg() *Expr

func (*Expr) Not

func (self *Expr) Not() *Expr

func (*Expr) Or

func (self *Expr) Or(v *Expr) *Expr

func (*Expr) Pow

func (self *Expr) Pow(v *Expr) *Expr

func (*Expr) Shl

func (self *Expr) Shl(v *Expr) *Expr

func (*Expr) Shr

func (self *Expr) Shr(v *Expr) *Expr

func (*Expr) Sub

func (self *Expr) Sub(v *Expr) *Expr

func (*Expr) Xor

func (self *Expr) Xor(v *Expr) *Expr

type Operator

type Operator uint8

Operator represents an operation to perform when Type is EXPR.

const (
	// ADD performs "Add Expr.Left and Expr.Right".
	ADD Operator = iota

	// SUB performs "Subtract Expr.Left by Expr.Right".
	SUB

	// MUL performs "Multiply Expr.Left by Expr.Right".
	MUL

	// DIV performs "Divide Expr.Left by Expr.Right".
	DIV

	// MOD performs "Modulo Expr.Left by Expr.Right".
	MOD

	// AND performs "Bitwise AND Expr.Left and Expr.Right".
	AND

	// OR performs "Bitwise OR Expr.Left and Expr.Right".
	OR

	// XOR performs "Bitwise XOR Expr.Left and Expr.Right".
	XOR

	// SHL performs "Bitwise Shift Expr.Left to the Left by Expr.Right Bits".
	SHL

	// SHR performs "Bitwise Shift Expr.Left to the Right by Expr.Right Bits".
	SHR

	// POW performs "Raise Expr.Left to the power of Expr.Right"
	POW

	// NOT performs "Bitwise Invert Expr.Left".
	NOT

	// NEG performs "Negate Expr.Left".
	NEG
)

func (Operator) String

func (self Operator) String() string

String returns the string representation of a Type.

type Parser

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

Parser parses an expression string to it's AST representation.

func (*Parser) Parse

func (self *Parser) Parse(repo Repository) (*Expr, error)

Parse parses the expression, and returns it's AST tree.

func (*Parser) SetSource

func (self *Parser) SetSource(src string) *Parser

SetSource resets the expression parser and sets the expression source.

type Repository

type Repository interface {
	Get(name string) (Term, error)
}

Repository represents a repository of Term's.

type RuntimeError

type RuntimeError struct {
	Reason string
}

RuntimeError is an error which would occure at run time.

func (*RuntimeError) Error

func (self *RuntimeError) Error() string

type SyntaxError

type SyntaxError struct {
	Pos    int
	Reason string
}

SyntaxError represents a syntax error in the expression.

func (*SyntaxError) Error

func (self *SyntaxError) Error() string

type Term

type Term interface {
	Free()
	Evaluate() (int64, error)
}

Term represents a value that can Evaluate() into an integer.

type Type

type Type int

Type is tyep expression type.

const (
	// CONST indicates that the expression is a constant.
	CONST Type = iota

	// TERM indicates that the expression is a Term reference.
	TERM

	// EXPR indicates that the expression is a unary or binary expression.
	EXPR
)

func (Type) String

func (self Type) String() string

String returns the string representation of a Type.