pql

package
v2.9.0 Latest Latest
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 Go to latest Published: Mar 4, 2021 License: Apache-2.0 Imports: 13 Imported by: 0

Documentation

Overview

Package pql defines the Pilosa Query Language.

Index

Constants

View Source 
const (
	// PrecallNone calls can be executed per shard.
	PrecallNone = CallType(iota)

	// PrecallGlobal indicates a call which must be run globally *before*
	// distributing the call to other shards. Example: A Distinct query,
	// where every shard could potentially produce results for any shard,
	// so you have to produce the results up front.
	// These are processed directly when inside of a count operation.
	PrecallGlobal

	// PrecallPerNode indicates a call which needs to be run per-shard
	// in a way that lets it be done on each shard, but where it should
	// be done prior to spawning per-shard goroutines. Example:
	// A cross-index query, where each local shard may or may not need
	// to get data from a remote node, but batches of shards can
	// probably be gotten from the same remote node.
	PrecallPerNode
)

Variables

This section is empty.

Functions

func CopyArgs 

func CopyArgs(m map[string]interface{}) map[string]interface{}

CopyArgs returns a copy of m.

func CopyArgsDecimalToFloat added in v2.3.0 

func CopyArgsDecimalToFloat(m map[string]interface{}) map[string]interface{}

CopyArgsDecimalToFloat makes a copy of m, but in the process, replaces any Decimal values with Float64 values.

func IsReservedArg 

func IsReservedArg(name string) bool

func MinMax 

func MinMax(scale int64) (Decimal, Decimal)

MinMax returns the minimum and maximum values supported by the provided scale.

func NewParser 

func NewParser(r io.Reader) *parser

NewParser returns a new instance of Parser.

func Pow10 

func Pow10(p int64) int64

Pow10 is a function which can be used in place of math.Pow10() to avoid the float64 logic. Note that only powers 0-18 are currently supported; anything else will return 0, which is probably going to result in incorrect values.

func Pretty 

func Pretty(pretty bool) func(*PQL) error

func Size 

func Size(size int) func(*PQL) error

func Unquote 

func Unquote(s string) (string, error)

Unquote interprets s as a single-quoted, double-quoted, or backquoted Go string literal, returning the string value that s quotes. It is a copy of stdlib's strconv.Unquote, but modified so that if s is single-quoted, it can still be a string rather than only character literal. This version of Unquote also accepts unquoted strings and passes them back unchanged.

Types

type Call 

type Call struct {
	Name        string
	Args        map[string]interface{}
	Children    []*Call
	Type        CallType
	Precomputed map[uint64]interface{}
}

Call represents a function call in the AST. The Precomputed field is used by the executor to handle non-standard call types; it does these by actually executing them separately, then replacing them in the call tree with a new call using the special precomputed type, with the Precomputed field set to a map from shards to results.

func (*Call) Arg 

func (c *Call) Arg(key string) (interface{}, bool)

Arg is for reading the value at key from call.Args. If the key is not in Call.Args, the value of the returned bool will be false.

func (*Call) ArgString 

func (c *Call) ArgString(key string) string

func (*Call) BoolArg 

func (c *Call) BoolArg(key string) (bool, bool, error)

BoolArg is for reading the value at key from call.Args as a bool. If the key is not in Call.Args, the value of the returned bool will be false, and the error will be nil. The value is assumed to be a bool. An error is returned if the value is not a bool.

func (*Call) CallArg 

func (c *Call) CallArg(key string) (*Call, bool, error)

CallArg is for reading the value at key from call.Args as a Call. If the key is not in Call.Args, the value of the returned value will be nil, and the error will be nil. An error is returned if the value is not a Call.

func (*Call) CallIndex 

func (c *Call) CallIndex() string

CallIndex handles guessing whether we've been asked to apply this to a different index. An empty string means "no".

func (*Call) CheckCallInfo 

func (c *Call) CheckCallInfo() error

CheckCallInfo tries to validate that arguments are correct and valid for the given call. It does not guarantee checking all possible errors; for instance, if an argument is a field name, CheckCallInfo can't validate that the field exists. It also updates with information like whether the call is expected to require precalling.

func (*Call) Clone 

func (c *Call) Clone() *Call

Clone returns a copy of c.

func (*Call) FieldArg 

func (c *Call) FieldArg() (string, error)

FieldArg determines which key-value pair contains the field and rowID, in the case of arguments like Set(colID, field=rowID). Returns the field as a string if present, or an error if not.

func (*Call) HasConditionArg 

func (c *Call) HasConditionArg() bool

HasConditionArg returns true if any arg is a conditional.

func (*Call) IntArg 

func (c *Call) IntArg(key string) (int64, bool, error)

IntArg is for reading the value at key from call.Args as an int64. If the key is not in Call.Args, the value of the returned bool will be false, and the error will be nil. The value is assumed to be a unt64 or an int64 and then cast to an int64. An error is returned if the value is not an int64 or uint64.

func (*Call) String 

func (c *Call) String() string

String returns the string representation of the call.

func (*Call) StringArg added in v2.1.8 

func (c *Call) StringArg(key string) (string, bool, error)

func (*Call) TranslateInfo 

func (c *Call) TranslateInfo(columnLabel, rowLabel string) (colKey, rowKey, fieldName string)

TranslateInfo returns the relevant translation fields.

func (*Call) UintArg 

func (c *Call) UintArg(key string) (uint64, bool, error)

UintArg is for reading the value at key from call.Args as a uint64. If the key is not in Call.Args, the value of the returned bool will be false, and the error will be nil. The value is assumed to be a uint64 or an int64 and then cast to a uint64. An error is returned if the value is not an int64 or uint64.

func (*Call) UintSliceArg 

func (c *Call) UintSliceArg(key string) ([]uint64, bool, error)

UintSliceArg reads the value at key from call.Args as a slice of uint64. If the key is not in Call.Args, the value of the returned bool will be false, and the error will be nil. If the value is a slice of int64 it will convert it to []uint64. Otherwise, if it is not a []uint64 it will return an error.

func (*Call) Writable added in v2.1.4 

func (c *Call) Writable() bool

Writable returns true if call is mutable (e.g. can write new translation keys)

type CallType 

type CallType byte

Some call types may require special handling, which needs to occur before distributing processing to individual shards.

type Condition 

type Condition struct {
	Op    Token
	Value interface{}
}

Condition represents an operation & value. When used in an argument map it represents a binary expression.

func (*Condition) Int64SliceValue 

func (cond *Condition) Int64SliceValue() ([]int64, bool)

func (*Condition) Int64Value 

func (cond *Condition) Int64Value() (int64, bool)

func (*Condition) String 

func (cond *Condition) String() string

String returns the string representation of the condition.

func (*Condition) StringSliceValue 

func (cond *Condition) StringSliceValue() ([]string, bool)

StringSliceValue returns the value(s) of the conditional as a slice of strings. For example, if cond.Value is []int64{-10,20}, this will return []string{"-10","20"}. It also returns a bool indicating that the conversion succeeded.

func (*Condition) StringWithSubj 

func (cond *Condition) StringWithSubj(subj string) string

StringWithSubj returns the string representation of the condition including the provided subject.

func (*Condition) Uint64SliceValue 

func (cond *Condition) Uint64SliceValue() ([]uint64, bool)

func (*Condition) Uint64Value 

func (cond *Condition) Uint64Value() (uint64, bool)

type Decimal 

type Decimal struct {
	Value int64
	Scale int64
}

Decimal represents a decimal value; the intention is to avoid relying on float64, and the primary purpose is to have a predictable way to encode such values used in query strings. Scale is the number of digits to the right of the decimal point. Precision is currently not considered; precision, for our purposes is implied to be the complete, known value.

func NewDecimal 

func NewDecimal(value, scale int64) Decimal

NewDecimal returns a Decimal based on the provided arguments.

func ParseDecimal 

func ParseDecimal(s string) (Decimal, error)

ParseDecimal parses a string into a Decimal.

func (Decimal) Clone added in v2.2.0 

func (d Decimal) Clone() (r *Decimal)

func (Decimal) EqualTo 

func (d Decimal) EqualTo(d2 Decimal) bool

EqualTo returns true if d == d2.

func (Decimal) Float64 

func (d Decimal) Float64() float64

Float64 returns d as a float64. TODO: this could potentially lose precision; we should audit its use and protect against unexpected results.

func (Decimal) GreaterThan 

func (d Decimal) GreaterThan(d2 Decimal) bool

GreaterThan returns true if d > d2.

func (Decimal) GreaterThanOrEqualTo 

func (d Decimal) GreaterThanOrEqualTo(d2 Decimal) bool

GreaterThanOrEqualTo returns true if d >= d2.

func (Decimal) IsValid 

func (d Decimal) IsValid() bool

IsValid returns true if the decimal does not break any assumption or resrictions on input.

func (Decimal) LessThan 

func (d Decimal) LessThan(d2 Decimal) bool

LessThan returns true if d < d2.

func (Decimal) LessThanOrEqualTo 

func (d Decimal) LessThanOrEqualTo(d2 Decimal) bool

LessThanOrEqualTo returns true if d <= d2.

func (Decimal) MarshalJSON 

func (d Decimal) MarshalJSON() ([]byte, error)

MarshalJSON is a custom marshaller for the Decimal type.

func (Decimal) MarshalYAML 

func (d Decimal) MarshalYAML() (interface{}, error)

MarshalYAML is a custom marshaller for the Decimal type.

func (Decimal) String 

func (d Decimal) String() string

String returns the string representation of the decimal.

func (Decimal) SupportedByScale 

func (d Decimal) SupportedByScale(scale int64) bool

SupportedByScale returns true if d can be represented by a decimal based on scale. For example: scale = 2: min: -92233720368547758.08 max: 92233720368547758.07 would not support: NewDecimal(9223372036854775807, 0)

func (Decimal) ToInt64 

func (d Decimal) ToInt64(scale int64) int64

ToInt64 returns d as an int64 adjusted to the provided scale.

func (*Decimal) UnmarshalJSON 

func (d *Decimal) UnmarshalJSON(data []byte) error

UnmarshalJSON is a custom unmarshaller for the Decimal type. The intention is to avoid the use of float64 anywhere, so this unmarhaller parses the decimal out of the byte string.

func (*Decimal) UnmarshalYAML 

func (d *Decimal) UnmarshalYAML(unmarshal func(interface{}) error) error

UnmarshalYAML is a custom unmarshaller for the Decimal type.

type PQL 

type PQL struct {
	Query

	Buffer string

	Pretty bool
	// contains filtered or unexported fields
}

func (*PQL) AST 

func (t *PQL) AST() *node32

func (*PQL) Add 

func (t *PQL) Add(rule pegRule, begin, end, index uint32)

func (*PQL) Execute 

func (p *PQL) Execute()

func (*PQL) Init 

func (p *PQL) Init(options ...func(*PQL) error) error

func (*PQL) Parse 

func (p *PQL) Parse(rule ...int) error

func (*PQL) PrettyPrintSyntaxTree 

func (t *PQL) PrettyPrintSyntaxTree(buffer string)

func (*PQL) Print 

func (t *PQL) Print()

func (*PQL) PrintSyntaxTree 

func (p *PQL) PrintSyntaxTree()

func (*PQL) Reset 

func (p *PQL) Reset()

func (*PQL) SprintSyntaxTree added in v2.1.4 

func (p *PQL) SprintSyntaxTree() string

func (*PQL) Tokens 

func (t *PQL) Tokens() []token32

func (*PQL) Trim 

func (t *PQL) Trim(length uint32)

func (*PQL) WriteSyntaxTree 

func (p *PQL) WriteSyntaxTree(w io.Writer)

type Query 

type Query struct {
	Calls []*Call
	// contains filtered or unexported fields
}

Query represents a PQL query.

func ParseString 

func ParseString(s string) (*Query, error)

ParseString parses s into a query.

func (*Query) String 

func (q *Query) String() string

String returns a string representation of the query.

func (*Query) WriteCallN 

func (q *Query) WriteCallN() int

WriteCallN returns the number of mutating calls.

type Token 

type Token int

Token is a lexical token of the PQL language. 

const (
	// Special tokens
	ILLEGAL Token = iota

	ASSIGN // =
	EQ     // ==
	NEQ    // !=
	LT     // <
	LTE    // <=
	GT     // >
	GTE    // >=

	BETWEEN // ><  (this is like a <= x <= b)

	// not used in lexing/parsing, but so that the parser can signal
	// to the executor how to treat the arguments. We used to just add
	// 1 to the arguments if they were LT so the executor could assume
	// it was always <=, <=, but then we needed to support
	// floats/decimals and couldn't do that any more.
	BTWN_LT_LTE // a < x <= b
	BTWN_LTE_LT // a <= x < b
	BTWN_LT_LT  // a < x < b
)

func (Token) String 

func (tok Token) String() string

String returns the string representation of the token.

Source Files

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