query_parser

package
v0.1.1 Latest Latest
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 Go to latest Published: Jan 7, 2019 License: BSD-3-Clause Imports: 11 Imported by: 0

Documentation

Overview

Package query_parser is a parser to parse a simplified select statement (a la SQL) for the Vanadium key value store (a.k.a., syncbase).

The select is of the form:

<query_specification> ::= 

<select_statement>
| <delete_statement>

<select_statement> ::= 

<select_clause> <from_clause> [<where_clause>] [<escape_limit_offset_clause>...]

<delete_statement> ::= 

delete <from_clause> [<where_clause>] [<escape_limit_clause>...]

<select_clause> ::= SELECT <selector> [{<comma><selector>}...]

<from_clause> ::= FROM <table>

<where_clause> ::= WHERE <expression>

<escape_limit_offset_clause> ::= 

ESCAPE <char_literal>
| LIMIT <int_literal>
| OFFSET <int_literal>

<escape_limit_clause> ::= 

ESCAPE <char_literal>
| LIMIT <int_literal>

<selector> ::= <column> [AS <string_literal>]

<column> ::= 

k
| v[<period><field>]
| <function>

<field> ::= <segment>[{<period><segment>}...]

<segment> ::= <identifier>[<keys>]

<keys> ::= <key>...

<key> ::= <left_bracket> <operand> <right_bracket>

<function> ::= <identifier><left_paren>[<operand>[{<comma><operand>}...]<right_paren>

<table> ::= <identifier>

<expression> ::= 

<left_paren> <expression> <right_paren>
| <logical_expression>
| <binary_expression>

<logical_expression> ::= 

<expression> <logical_op> <expression>

<logical_op> ::= 

AND
| OR

<binary_expression> ::= 

<operand> <binary_op> <operand>
| v[<period><field>] IS [NOT] NIL

<operand> ::= 

k
| v[<period><field>]
| <literal>
| <function>

<binary_op> ::= 

=
| EQUAL
| <>
| NOT EQUAL
| LIKE
| NOT LIKE
| <
| <=
| >=
| >

<literal> ::= 

<string_literal>
| <bool_literal>
| <int_literal>
| <float_literal>

Example: select v.Foo.Far, v.Baz[2] from Foobarbaz where Type(v) like "%.Customer" and (v.Foo = 42 and v.Bar not like "abc%) or (k >= "100" and k < "200")

Index

Constants

View Source 
const (
	MaxStatementLen = 10000
)

Variables

This section is empty.

Functions

This section is empty.

Types

type AsClause 

type AsClause struct {
	AltName Name
	Node
}

func (AsClause) String 

func (a AsClause) String() string

type BinaryOperator 

type BinaryOperator struct {
	Type BinaryOperatorType
	Node
}

func (BinaryOperator) String 

func (o BinaryOperator) String() string

type BinaryOperatorType 

type BinaryOperatorType int
const (
	And BinaryOperatorType = 1 + iota
	Equal
	GreaterThan
	GreaterThanOrEqual
	Is
	IsNot
	LessThan
	LessThanOrEqual
	Like
	NotEqual
	NotLike
	Or
)

type CharValue 

type CharValue struct {
	Value rune
	Node
}

func (CharValue) String 

func (c CharValue) String() string

type DeleteStatement 

type DeleteStatement struct {
	From   *FromClause
	Where  *WhereClause
	Escape *EscapeClause
	Limit  *LimitClause
	Node
}

func (DeleteStatement) CopyAndSubstitute 

func (st DeleteStatement) CopyAndSubstitute(db ds.Database, paramValues []*vdl.Value) (Statement, error)

func (DeleteStatement) Offset 

func (st DeleteStatement) Offset() int64

func (DeleteStatement) String 

func (st DeleteStatement) String() string

Pretty string of delete statement.

type EscapeClause 

type EscapeClause struct {
	EscapeChar *CharValue
	Node
}

func (EscapeClause) String 

func (e EscapeClause) String() string

type Expression 

type Expression struct {
	Operand1 *Operand
	Operator *BinaryOperator
	Operand2 *Operand
	Node
}

func (Expression) CopyAndSubstitute 

func (e Expression) CopyAndSubstitute(db ds.Database, pi *paramInfo) (*Expression, error)

func (Expression) String 

func (e Expression) String() string

type Field 

type Field struct {
	Segments []Segment
	Node
}

func ParseIndexField 

func ParseIndexField(db ds.Database, fieldName, tableName string) (*Field, error)

ParseIndexField is used to parse datasource supplied index fields. It creates a new scanner with the contents of the field name and only succeeds if the result of parsing the contents of the scan is a field and there is nothing left over. Note: This function is NOT involved in the parsing of the AST. Offsets of 0 are 

returned on error as these errors are unrelated to the input query.  They
are configuration errors in the datasource.

func (Field) String 

func (f Field) String() string

type FromClause 

type FromClause struct {
	Table TableEntry
	Node
}

func (FromClause) String 

func (f FromClause) String() string

type Function 

type Function struct {
	Name     string
	Args     []*Operand
	ArgTypes []OperandType // Filled in by checker.
	RetType  OperandType   // Filled in by checker.
	Computed bool          // Checker sets to true and sets RetValue if function takes no args
	RetValue *Operand
	Node
}

func (Function) CopyAndSubstitute 

func (f Function) CopyAndSubstitute(db ds.Database, pi *paramInfo) (*Function, error)

func (Function) String 

func (f Function) String() string

type Int64Value 

type Int64Value struct {
	Value int64
	Node
}

func (Int64Value) String 

func (i Int64Value) String() string

type LimitClause 

type LimitClause struct {
	Limit *Int64Value
	Node
}

func (LimitClause) String 

func (l LimitClause) String() string

type Name 

type Name struct {
	Value string
	Node
}

func (Name) String 

func (n Name) String() string

type Node 

type Node struct {
	Off int64
}

type Operand 

type Operand struct {
	Type     OperandType
	BigInt   *big.Int
	BigRat   *big.Rat
	Bool     bool
	Column   *Field
	Float    float64
	Function *Function
	Int      int64
	Str      string
	Time     time.Time
	Prefix   string           // Computed by checker for Like expressions
	Pattern  *pattern.Pattern // Computed by checker for Like expressions
	Uint     uint64
	Expr     *Expression
	Object   *vdl.Value
	Node
}

func ConvertValueToAnOperand 

func ConvertValueToAnOperand(value *vdl.Value, off int64) (*Operand, error)

func (Operand) CopyAndSubstitute 

func (o Operand) CopyAndSubstitute(db ds.Database, pi *paramInfo) (*Operand, error)

func (Operand) String 

func (o Operand) String() string

type OperandType 

type OperandType int
const (
	TypBigInt OperandType = 1 + iota // Only as a result of Resolve/Coerce Operand
	TypBigRat                        // Only as a result of Resolve/Coerce Operand
	TypBool
	TypExpr
	TypField
	TypFloat
	TypFunction
	TypInt
	TypNil
	TypParameter
	TypStr
	TypTime
	TypObject // Only as the result of a ResolveOperand
	TypUint   // Only as the result of a ResolveOperand
)

type ResultsOffsetClause 

type ResultsOffsetClause struct {
	ResultsOffset *Int64Value
	Node
}

func (ResultsOffsetClause) String 

func (l ResultsOffsetClause) String() string

type Segment 

type Segment struct {
	Value string
	Keys  []*Operand // Used as key(s) or index(es) to dereference map/set/array/list.
	Node
}

func (Segment) String 

func (s Segment) String() string

type SelectClause 

type SelectClause struct {
	Selectors []Selector
	Node
}

func (SelectClause) String 

func (sel SelectClause) String() string

type SelectStatement 

type SelectStatement struct {
	Select        *SelectClause
	From          *FromClause
	Where         *WhereClause
	Escape        *EscapeClause
	Limit         *LimitClause
	ResultsOffset *ResultsOffsetClause
	Node
}

func (SelectStatement) CopyAndSubstitute 

func (st SelectStatement) CopyAndSubstitute(db ds.Database, paramValues []*vdl.Value) (Statement, error)

func (SelectStatement) Offset 

func (st SelectStatement) Offset() int64

func (SelectStatement) String 

func (st SelectStatement) String() string

Pretty string of select statement.

type Selector 

type Selector struct {
	Type     SelectorType
	Field    *Field
	Function *Function
	As       *AsClause // If not nil, used in returned column header.
	Node
}

Selector: entries in the select clause. Entries can be functions for fields. The AS name, if present, will ONLY be used in the returned column header.

func (Selector) String 

func (s Selector) String() string

type SelectorType 

type SelectorType int
const (
	TypSelField SelectorType = 1 + iota
	TypSelFunc
)

type Statement 

type Statement interface {
	Offset() int64
	String() string
	CopyAndSubstitute(db ds.Database, paramValues []*vdl.Value) (Statement, error)
}

func Parse 

func Parse(db ds.Database, src string) (*Statement, error)

Parse a statement. Return it or an error.

type TableEntry 

type TableEntry struct {
	Name    string
	DBTable ds.Table // Checker gets table from db and sets this.
	Node
}

func (TableEntry) String 

func (t TableEntry) String() string

type Token 

type Token struct {
	Tok   TokenType
	Value string
	Off   int64
}

type TokenType 

type TokenType int
const (
	TokCHAR TokenType = 1 + iota
	TokCOMMA
	TokEOF
	TokEQUAL
	TokFLOAT
	TokIDENT
	TokINT
	TokLEFTANGLEBRACKET
	TokLEFTBRACKET
	TokLEFTPAREN
	TokMINUS
	TokParameter // allowed only in prepared statements
	TokPERIOD
	TokRIGHTANGLEBRACKET
	TokRIGHTBRACKET
	TokRIGHTPAREN
	TokSTRING
	TokERROR
)

type WhereClause 

type WhereClause struct {
	Expr *Expression
	Node
}

func (WhereClause) CopyAndSubstitute 

func (w WhereClause) CopyAndSubstitute(db ds.Database, paramValues []*vdl.Value) (*WhereClause, error)

func (WhereClause) String 

func (w WhereClause) String() string

Source Files

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