exp

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 Go to latest Published: Aug 18, 2026 License: Apache-2.0 Imports: 1 Imported by: 13

README

Expressions 🤩

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Easy Expression Builder for Golang

Every database has its own query language, so this library provides an intermediate format that should be easy to convert into whatever specific language you need to use.

The expression library only represents the structure of the logical expression, and does not include implementations for any data sources. Those should be implemented in each individual data source adapter library.


// build single predicate expressions
criteria := exp.Equal("_id", 42)

// use chaining for logical constructs
criteria := exp.Equal("_id", 42).AndEqual("deleteDate",  0)
criteria := exp.Equal("name", "John").OrEqual("name", "Sarah")

// Also supports complex and/or logic

criteria := exp.Or(
    exp.Equal("_id", 42).AndEqual("deleteDate",  0),
    exp.Equal("_id", 42).AndEqual("name", "Sarah"),
)

// Constants define standard expected operators
exp.OperatorEqual          = "="
exp.OperatorNotEqual       = "!="
exp.OperatorLessThan       = "<"
exp.OperatorLessOrEqual    = "<="
exp.OperatorGreaterThan    = ">"
exp.OperatorGreaterOrEqual = ">="
exp.OperatorIn             = "IN"
exp.OperatorNotIn          = "NOT IN"
exp.OperatorInAll          = "IN ALL"
exp.OperatorBeginsWith     = "BEGINS"
exp.OperatorEndsWith       = "ENDS"
exp.OperatorContains       = "CONTAINS"
exp.OperatorContainedBy    = "CONTAINED BY"
exp.OperatorExists         = "EXISTS"
exp.OperatorGeoWithin      = "GEO-WITHIN"
exp.OperatorGeoIntersects  = "GEO-INTERSECTS"

Interfaces

This is accomplished with three very similar data types that all implement the same Expression interface.

Predicate represents a single predicate/comparison. Using .And() and .Or() will return the corresponding AndExpression or OrExpression object

AndExpression represents multiple predicates, all chained together with AND logic. Additional predicates added with .And() are appended to the same expression; .Or() nests it inside a new OrExpression.

OrExpression represents multiple predicates, all chained together with OR logic. Additional predicates added with .Or() are appended to the same expression; .And() nests it inside a new AndExpression.

EmptyExpression represents "no constraint at all". It matches everything, and is absorbed whenever it is combined with another expression. A nil Expression is treated the same way, so a missing constraint can never become a nil that panics later during .Match().

Manually Walking the Logic Tree

Each of the three interfaces above implements a .Match() function that can be used by external programs to see if a dataset matches this expression. You must pass in a MatcherFunc that accepts a predicate and returns TRUE if that predicate matches the dataset. AndExpression and OrExpression objects will call this function repeatedly for each element in their logic tree, and return a final boolean value for the entire logic structure.

Pull Requests Welcome

This library is a work in progress, and will benefit from your experience reports, use cases, and contributions. If you have an idea for making this library better, send in a pull request. We're all in this together! 🤩

Documentation

Overview

Package exp builds database-agnostic query expressions.

Every database has its own query language, so this package provides an intermediate format that adapter libraries translate into whatever dialect they need. It describes only the shape of a logical expression, and contains no implementation for any particular data source.

Expressions are built from four types, all of which satisfy the Expression interface: 

Predicate        a single comparison, such as `name = "Sarah"`
AndExpression    a list of sub-expressions, all of which must match
OrExpression     a list of sub-expressions, any one of which may match
EmptyExpression  no constraint at all, which matches everything

Predicates chain into larger expressions using the And* and Or* methods: 

criteria := exp.Equal("_id", 42).AndEqual("deleteDate", 0)

To walk a finished expression, pass a MatcherFunc to its Match method. The MatcherFunc answers "does this one Predicate match my data?" and the Expression handles the boolean logic around it.

Index

Constants

View Source 
const OperatorBeginsWith = "BEGINS"

OperatorBeginsWith represents a "begins with" comparison, when used in Predicates and Criteria. It is only valid for string values.

View Source 
const OperatorContainedBy = "CONTAINED BY"

OperatorContainedBy represents a "contained by" comparison, when used in Predicates and Criteria. It is only valid for string values.

View Source 
const OperatorContains = "CONTAINS"

OperatorContains represents a "contains" comparison, when used in Predicates and Criteria. It is only valid for string values.

View Source 
const OperatorEndsWith = "ENDS"

OperatorEndsWith represents a "ends with" comparison, when used in Predicates and Criteria. It is only valid for string values.

View Source 
const OperatorEqual = "="

OperatorEqual represents an "equals" comparison, when used in Predicates and Criteria

View Source 
const OperatorExists = "EXISTS"

OperatorExists represents an "exists" comparison, which should return TRUE if the provided field exists.

View Source 
const OperatorGeoIntersects = "GEO-INTERSECTS"

OperatorGeoIntersects represents a geometric search that intersects with a given shape

View Source 
const OperatorGeoWithin = "GEO-WITHIN"

OperatorGeoWithin represents a geometric search within a given shape.

View Source 
const OperatorGreaterOrEqual = ">="

OperatorGreaterOrEqual represents an "greater or equal" comparison, when used in Predicates and Criteria

View Source 
const OperatorGreaterThan = ">"

OperatorGreaterThan represents an "greater than" comparison, when used in Predicates and Criteria

View Source 
const OperatorIn = "IN"

OperatorIn represents a "in" comparison, when used in Predicates and Criteria.

View Source 
const OperatorInAll = "IN ALL"

OperatorInAll represents an "in all" comparison, when used in Predicates and Criteria.

View Source 
const OperatorLessOrEqual = "<="

OperatorLessOrEqual represents an "less or equal" comparison, when used in Predicates and Criteria

View Source 
const OperatorLessThan = "<"

OperatorLessThan represents a "less than" comparison, when used in Predicates and Criteria

View Source 
const OperatorNotEqual = "!="

OperatorNotEqual represents a "not equals" comparison, when used in Predicates and Criteria

View Source 
const OperatorNotIn = "NOT IN"

OperatorNotIn represents a "not in" comparison, when used in Predicates and Criteria.

Variables

This section is empty.

Functions

func Operator added in v0.1.0 

func Operator(value string) string

Operator tries to convert non-standard values into standard operators.

func OperatorOk added in v0.8.1 

func OperatorOk(value string) (string, bool)

OperatorOk converts a non-standard value into a standard operator constant, returning the standardized operator and TRUE when the value is recognized.

Types

type AndExpression 

type AndExpression []Expression

AndExpression combines a series of sub-expressions using AND logic

func All 

func All() AndExpression

All returns an Expression that matches every record in a dataset.

func And 

func And(expressions ...Expression) AndExpression

And combines one or more expression parameters into an AndExpression

func (AndExpression) And 

func (e AndExpression) And(exp Expression) Expression

And is a part of the Expression interface. It combines another expression into a new AndExpression

func (AndExpression) AndEqual 

func (e AndExpression) AndEqual(name string, value any) Expression

AndEqual is a part of the Expression interface. It creates a new AndExpression using the Equal comparison

func (AndExpression) AndGreaterOrEqual 

func (e AndExpression) AndGreaterOrEqual(name string, value any) Expression

AndGreaterOrEqual is a part of the Expression interface. It creates a new AndExpression using the GreaterOrEqual comparison

func (AndExpression) AndGreaterThan 

func (e AndExpression) AndGreaterThan(name string, value any) Expression

AndGreaterThan is a part of the Expression interface. It creates a new AndExpression using the GreaterThan comparison

func (AndExpression) AndIn added in v0.1.2 

func (e AndExpression) AndIn(name string, value any) Expression

AndIn is a part of the Expression interface. It creates a new AndExpression using the In comparison

func (AndExpression) AndInAll added in v0.8.4 

func (e AndExpression) AndInAll(field string, values ...any) Expression

AndInAll is a part of the Expression interface. It creates a new AndExpression using the InAll comparison

func (AndExpression) AndLessOrEqual 

func (e AndExpression) AndLessOrEqual(name string, value any) Expression

AndLessOrEqual is a part of the Expression interface. It creates a new AndExpression using the LessOrEqual comparison

func (AndExpression) AndLessThan 

func (e AndExpression) AndLessThan(name string, value any) Expression

AndLessThan is a part of the Expression interface. It creates a new AndExpression using the LessThan comparison

func (AndExpression) AndNotEqual 

func (e AndExpression) AndNotEqual(name string, value any) Expression

AndNotEqual is a part of the Expression interface. It creates a new AndExpression using the NotEqual comparison

func (AndExpression) AndNotIn added in v0.1.2 

func (e AndExpression) AndNotIn(name string, value any) Expression

AndNotIn is a part of the Expression interface. It creates a new AndExpression using the NotIn comparison

func (AndExpression) Fields added in v0.8.5 

func (e AndExpression) Fields() []string

Fields is a part of the Expression interface. It returns a slice of field names that are used in this expression.

func (AndExpression) IsEmpty added in v0.8.0 

func (e AndExpression) IsEmpty() bool

IsEmpty is a part of the Expression interface. It returns TRUE if an expression does not have any predicates

func (AndExpression) Match 

func (e AndExpression) Match(fn MatcherFunc) bool

Match is a part of the Expression interface. It loops through all sub-expressions and returns TRUE if all of them match

func (AndExpression) NotEmpty added in v0.8.0 

func (e AndExpression) NotEmpty() bool

NotEmpty is a part of the Expression interface. It returns TRUE if an expression has one or more predicates

func (AndExpression) Or added in v0.1.0 

func (e AndExpression) Or(exp Expression) Expression

Or is a part of the Expression interface. It combines this AndExpression with another expression into a new OrExpression

func (AndExpression) OrEqual added in v0.10.0 

func (e AndExpression) OrEqual(name string, value any) Expression

OrEqual is a part of the Expression interface. It creates a new OrExpression using the Equal comparison

func (AndExpression) OrGreaterOrEqual added in v0.10.0 

func (e AndExpression) OrGreaterOrEqual(name string, value any) Expression

OrGreaterOrEqual is a part of the Expression interface. It creates a new OrExpression using the GreaterOrEqual comparison

func (AndExpression) OrGreaterThan added in v0.10.0 

func (e AndExpression) OrGreaterThan(name string, value any) Expression

OrGreaterThan is a part of the Expression interface. It creates a new OrExpression using the GreaterThan comparison

func (AndExpression) OrIn added in v0.10.0 

func (e AndExpression) OrIn(name string, value any) Expression

OrIn is a part of the Expression interface. It creates a new OrExpression using the In comparison

func (AndExpression) OrInAll added in v0.10.0 

func (e AndExpression) OrInAll(field string, values ...any) Expression

OrInAll is a part of the Expression interface. It creates a new OrExpression using the InAll comparison

func (AndExpression) OrLessOrEqual added in v0.10.0 

func (e AndExpression) OrLessOrEqual(name string, value any) Expression

OrLessOrEqual is a part of the Expression interface. It creates a new OrExpression using the LessOrEqual comparison

func (AndExpression) OrLessThan added in v0.10.0 

func (e AndExpression) OrLessThan(name string, value any) Expression

OrLessThan is a part of the Expression interface. It creates a new OrExpression using the LessThan comparison

func (AndExpression) OrNotEqual added in v0.10.0 

func (e AndExpression) OrNotEqual(name string, value any) Expression

OrNotEqual is a part of the Expression interface. It creates a new OrExpression using the NotEqual comparison

func (AndExpression) OrNotIn added in v0.10.0 

func (e AndExpression) OrNotIn(name string, value any) Expression

OrNotIn is a part of the Expression interface. It creates a new OrExpression using the NotIn comparison

type EmptyExpression added in v0.1.0 

type EmptyExpression struct{}

EmptyExpression is an implementation of the Expression interface that represents an empty expression.

func Empty added in v0.1.0 

func Empty() EmptyExpression

Empty creates and returns a new EmptyExpression.

func (EmptyExpression) And added in v0.1.0 

func (e EmptyExpression) And(exp Expression) Expression

And is a part of the Expression interface. It returns the other expression, which absorbs this empty one.

func (EmptyExpression) AndEqual added in v0.1.2 

func (e EmptyExpression) AndEqual(name string, value any) Expression

AndEqual is a part of the Expression interface. It returns an Equal predicate, since there is no existing expression to combine with.

func (EmptyExpression) AndGreaterOrEqual added in v0.1.2 

func (e EmptyExpression) AndGreaterOrEqual(name string, value any) Expression

AndGreaterOrEqual is a part of the Expression interface. It returns a GreaterOrEqual predicate, since there is no existing expression to combine with.

func (EmptyExpression) AndGreaterThan added in v0.1.2 

func (e EmptyExpression) AndGreaterThan(name string, value any) Expression

AndGreaterThan is a part of the Expression interface. It returns a GreaterThan predicate, since there is no existing expression to combine with.

func (EmptyExpression) AndIn added in v0.1.2 

func (e EmptyExpression) AndIn(name string, value any) Expression

AndIn is a part of the Expression interface. It returns an In predicate, since there is no existing expression to combine with.

func (EmptyExpression) AndInAll added in v0.8.4 

func (e EmptyExpression) AndInAll(name string, value ...any) Expression

AndInAll is a part of the Expression interface. It returns an InAll predicate, since there is no existing expression to combine with.

func (EmptyExpression) AndLessOrEqual added in v0.1.2 

func (e EmptyExpression) AndLessOrEqual(name string, value any) Expression

AndLessOrEqual is a part of the Expression interface. It returns a LessOrEqual predicate, since there is no existing expression to combine with.

func (EmptyExpression) AndLessThan added in v0.1.2 

func (e EmptyExpression) AndLessThan(name string, value any) Expression

AndLessThan is a part of the Expression interface. It returns a LessThan predicate, since there is no existing expression to combine with.

func (EmptyExpression) AndNotEqual added in v0.1.2 

func (e EmptyExpression) AndNotEqual(name string, value any) Expression

AndNotEqual is a part of the Expression interface. It returns a NotEqual predicate, since there is no existing expression to combine with.

func (EmptyExpression) AndNotIn added in v0.1.2 

func (e EmptyExpression) AndNotIn(name string, value any) Expression

AndNotIn is a part of the Expression interface. It returns a NotIn predicate, since there is no existing expression to combine with.

func (EmptyExpression) Fields added in v0.8.5 

func (e EmptyExpression) Fields() []string

Fields is a part of the Expression interface. It returns an empty slice since there are no fields in an EmptyExpression.

func (EmptyExpression) IsEmpty added in v0.8.0 

func (e EmptyExpression) IsEmpty() bool

IsEmpty is a part of the Expression interface. It always returns TRUE for an EmptyExpression, since it is always empty.

func (EmptyExpression) Match added in v0.1.0 

func (e EmptyExpression) Match(_ MatcherFunc) bool

Match is a part of the Expression interface. It always returns TRUE for an EmptyExpression, since it matches everything.

func (EmptyExpression) NotEmpty added in v0.8.0 

func (e EmptyExpression) NotEmpty() bool

NotEmpty is a part of the Expression interface. It always returns FALSE for an EmptyExpression, since it is always empty.

func (EmptyExpression) Or added in v0.1.0 

func (e EmptyExpression) Or(exp Expression) Expression

Or is a part of the Expression interface. It returns the other expression, which absorbs this empty one.

func (EmptyExpression) OrEqual added in v0.10.0 

func (e EmptyExpression) OrEqual(name string, value any) Expression

OrEqual is a part of the Expression interface. It returns an Equal predicate, since there is no existing expression to combine with.

func (EmptyExpression) OrGreaterOrEqual added in v0.10.0 

func (e EmptyExpression) OrGreaterOrEqual(name string, value any) Expression

OrGreaterOrEqual is a part of the Expression interface. It returns a GreaterOrEqual predicate, since there is no existing expression to combine with.

func (EmptyExpression) OrGreaterThan added in v0.10.0 

func (e EmptyExpression) OrGreaterThan(name string, value any) Expression

OrGreaterThan is a part of the Expression interface. It returns a GreaterThan predicate, since there is no existing expression to combine with.

func (EmptyExpression) OrIn added in v0.10.0 

func (e EmptyExpression) OrIn(name string, value any) Expression

OrIn is a part of the Expression interface. It returns an In predicate, since there is no existing expression to combine with.

func (EmptyExpression) OrInAll added in v0.10.0 

func (e EmptyExpression) OrInAll(name string, value ...any) Expression

OrInAll is a part of the Expression interface. It returns an InAll predicate, since there is no existing expression to combine with.

func (EmptyExpression) OrLessOrEqual added in v0.10.0 

func (e EmptyExpression) OrLessOrEqual(name string, value any) Expression

OrLessOrEqual is a part of the Expression interface. It returns a LessOrEqual predicate, since there is no existing expression to combine with.

func (EmptyExpression) OrLessThan added in v0.10.0 

func (e EmptyExpression) OrLessThan(name string, value any) Expression

OrLessThan is a part of the Expression interface. It returns a LessThan predicate, since there is no existing expression to combine with.

func (EmptyExpression) OrNotEqual added in v0.10.0 

func (e EmptyExpression) OrNotEqual(name string, value any) Expression

OrNotEqual is a part of the Expression interface. It returns a NotEqual predicate, since there is no existing expression to combine with.

func (EmptyExpression) OrNotIn added in v0.10.0 

func (e EmptyExpression) OrNotIn(name string, value any) Expression

OrNotIn is a part of the Expression interface. It returns a NotIn predicate, since there is no existing expression to combine with.

type Expression 

type Expression interface {

	// Match evaluates the expression against a MatcherFunc, returning TRUE if the expression matches
	Match(MatcherFunc) bool

	// And returns a new expression that combines this expression with another as an AndExpression
	And(Expression) Expression

	// AndEqual is a shortcut that creates a new AndExpression using the Equal comparison
	AndEqual(name string, value any) Expression

	// AndNotEqual is a shortcut that creates a new AndExpression using the NotEqual comparison
	AndNotEqual(name string, value any) Expression

	// AndLessThan is a shortcut that creates a new AndExpression using the LessThan comparison
	AndLessThan(name string, value any) Expression

	// AndLessOrEqual is a shortcut that creates a new AndExpression using the LessOrEqual comparison
	AndLessOrEqual(name string, value any) Expression

	// AndGreaterThan is a shortcut that creates a new AndExpression using the GreaterThan comparison
	AndGreaterThan(name string, value any) Expression

	// AndGreaterOrEqual is a shortcut that creates a new AndExpression using the GreaterOrEqual comparison
	AndGreaterOrEqual(name string, value any) Expression

	// AndIn is a shortcut that creates a new AndExpression using the In comparison
	AndIn(name string, value any) Expression

	// AndNotIn is a shortcut that creates a new AndExpression using the NotIn comparison
	AndNotIn(name string, value any) Expression

	// AndInAll is a shortcut that creates a new AndExpression using the InAll comparison
	AndInAll(name string, value ...any) Expression

	// Or returns a new expression that combines this expression with another as an OrExpression
	Or(Expression) Expression

	// OrEqual is a shortcut that creates a new OrExpression using the Equal comparison
	OrEqual(name string, value any) Expression

	// OrNotEqual is a shortcut that creates a new OrExpression using the NotEqual comparison
	OrNotEqual(name string, value any) Expression

	// OrLessThan is a shortcut that creates a new OrExpression using the LessThan comparison
	OrLessThan(name string, value any) Expression

	// OrLessOrEqual is a shortcut that creates a new OrExpression using the LessOrEqual comparison
	OrLessOrEqual(name string, value any) Expression

	// OrGreaterThan is a shortcut that creates a new OrExpression using the GreaterThan comparison
	OrGreaterThan(name string, value any) Expression

	// OrGreaterOrEqual is a shortcut that creates a new OrExpression using the GreaterOrEqual comparison
	OrGreaterOrEqual(name string, value any) Expression

	// OrIn is a shortcut that creates a new OrExpression using the In comparison
	OrIn(name string, value any) Expression

	// OrNotIn is a shortcut that creates a new OrExpression using the NotIn comparison
	OrNotIn(name string, value any) Expression

	// OrInAll is a shortcut that creates a new OrExpression using the InAll comparison
	OrInAll(name string, value ...any) Expression

	// IsEmpty returns TRUE if an expression does not have any predicates
	IsEmpty() bool

	// NotEmpty returns TRUE if an expression has one or more predicates
	NotEmpty() bool

	// Fields returns the list of fields that are used in this expression
	Fields() []string
}

Expression is an interface that is implemented by Predicates, AndExpressions, and OrExpressions. It enables any of these items to be embedded into the criteria of a data.Query

func Parse added in v0.7.0 

func Parse(value string) Expression

Parse converts a "field operator value" string into an Expression.

type GeoJSONer added in v0.9.0 

type GeoJSONer interface {

	// GeoJSON returns a GeoJSON representation of the object
	GeoJSON() map[string]any
}

GeoJSONer is an interface for types that can represent themselves as GeoJSON

type MatcherFunc 

type MatcherFunc func(Predicate) bool

MatcherFunc reports whether a single Predicate matches the caller's data. It is passed to the Match method of every Expression.

type OrExpression 

type OrExpression []Expression

OrExpression compares a series of sub-expressions, using the OR logic

func Or 

func Or(expressions ...Expression) OrExpression

Or combines one or more expression parameters into an OrExpression

func (OrExpression) And added in v0.1.0 

func (e OrExpression) And(exp Expression) Expression

And is a part of the Expression interface It combines this OrExpression with another expression into a new AndExpression

func (OrExpression) AndEqual added in v0.1.2 

func (e OrExpression) AndEqual(name string, value any) Expression

AndEqual is a part of the Expression interface. It creates a new AndExpression using the Equal comparison

func (OrExpression) AndGreaterOrEqual added in v0.1.2 

func (e OrExpression) AndGreaterOrEqual(name string, value any) Expression

AndGreaterOrEqual is a part of the Expression interface. It creates a new AndExpression using the GreaterOrEqual comparison

func (OrExpression) AndGreaterThan added in v0.1.2 

func (e OrExpression) AndGreaterThan(name string, value any) Expression

AndGreaterThan is a part of the Expression interface. It creates a new AndExpression using the GreaterThan comparison

func (OrExpression) AndIn added in v0.1.2 

func (e OrExpression) AndIn(name string, value any) Expression

AndIn is a part of the Expression interface. It creates a new AndExpression using the In comparison

func (OrExpression) AndInAll added in v0.8.4 

func (e OrExpression) AndInAll(field string, values ...any) Expression

AndInAll is a part of the Expression interface. It creates a new AndExpression using the InAll comparison

func (OrExpression) AndLessOrEqual added in v0.1.2 

func (e OrExpression) AndLessOrEqual(name string, value any) Expression

AndLessOrEqual is a part of the Expression interface. It creates a new AndExpression using the LessOrEqual comparison

func (OrExpression) AndLessThan added in v0.1.2 

func (e OrExpression) AndLessThan(name string, value any) Expression

AndLessThan is a part of the Expression interface. It creates a new AndExpression using the LessThan comparison

func (OrExpression) AndNotEqual added in v0.1.2 

func (e OrExpression) AndNotEqual(name string, value any) Expression

AndNotEqual is a part of the Expression interface. It creates a new AndExpression using the NotEqual comparison

func (OrExpression) AndNotIn added in v0.1.2 

func (e OrExpression) AndNotIn(name string, value any) Expression

AndNotIn is a part of the Expression interface. It creates a new AndExpression using the NotIn comparison

func (OrExpression) Fields added in v0.8.5 

func (e OrExpression) Fields() []string

Fields is a part of the Expression interface. It returns a slice of field names that are used in this expression.

func (OrExpression) IsEmpty added in v0.8.0 

func (e OrExpression) IsEmpty() bool

IsEmpty is a part of the Expression interface. It returns TRUE if an expression does not have any predicates

func (OrExpression) Match 

func (e OrExpression) Match(fn MatcherFunc) bool

Match is a part of the Expression interface. It loops through all sub-expressions and returns TRUE if any of them match

func (OrExpression) NotEmpty added in v0.8.0 

func (e OrExpression) NotEmpty() bool

NotEmpty is a part of the Expression interface. It returns TRUE if an expression has one or more predicates

func (OrExpression) Or 

func (e OrExpression) Or(exp Expression) Expression

Or is a part of the Expression interface. It combines another expression into a new OrExpression

func (OrExpression) OrEqual added in v0.10.0 

func (e OrExpression) OrEqual(name string, value any) Expression

OrEqual is a part of the Expression interface. It creates a new OrExpression using the Equal comparison

func (OrExpression) OrGreaterOrEqual added in v0.10.0 

func (e OrExpression) OrGreaterOrEqual(name string, value any) Expression

OrGreaterOrEqual is a part of the Expression interface. It creates a new OrExpression using the GreaterOrEqual comparison

func (OrExpression) OrGreaterThan added in v0.10.0 

func (e OrExpression) OrGreaterThan(name string, value any) Expression

OrGreaterThan is a part of the Expression interface. It creates a new OrExpression using the GreaterThan comparison

func (OrExpression) OrIn added in v0.10.0 

func (e OrExpression) OrIn(name string, value any) Expression

OrIn is a part of the Expression interface. It creates a new OrExpression using the In comparison

func (OrExpression) OrInAll added in v0.10.0 

func (e OrExpression) OrInAll(field string, values ...any) Expression

OrInAll is a part of the Expression interface. It creates a new OrExpression using the InAll comparison

func (OrExpression) OrLessOrEqual added in v0.10.0 

func (e OrExpression) OrLessOrEqual(name string, value any) Expression

OrLessOrEqual is a part of the Expression interface. It creates a new OrExpression using the LessOrEqual comparison

func (OrExpression) OrLessThan added in v0.10.0 

func (e OrExpression) OrLessThan(name string, value any) Expression

OrLessThan is a part of the Expression interface. It creates a new OrExpression using the LessThan comparison

func (OrExpression) OrNotEqual added in v0.10.0 

func (e OrExpression) OrNotEqual(name string, value any) Expression

OrNotEqual is a part of the Expression interface. It creates a new OrExpression using the NotEqual comparison

func (OrExpression) OrNotIn added in v0.10.0 

func (e OrExpression) OrNotIn(name string, value any) Expression

OrNotIn is a part of the Expression interface. It creates a new OrExpression using the NotIn comparison

type Predicate 

type Predicate struct {

	// Field is the name of the value being compared, in the data source's own naming scheme
	Field string

	// Operator is one of the Operator* constants, naming the comparison to perform
	Operator string

	// Value is the value that the Field is compared against
	Value any
}

Predicate represents a single true/false comparison

func BeginsWith 

func BeginsWith(field string, value any) Predicate

BeginsWith creates a new Predicate using an "BeginsWith" comparison

func ContainedBy added in v0.1.0 

func ContainedBy(field string, value any) Predicate

ContainedBy creates a new Predicate using an "ContainedBy" comparison

func Contains 

func Contains(field string, value any) Predicate

Contains creates a new Predicate using an "Contains" comparison

func EndsWith 

func EndsWith(field string, value any) Predicate

EndsWith creates a new Predicate using an "EndsWith" comparison

func Equal 

func Equal(field string, value any) Predicate

Equal creates a new Predicate using an "Equals" comparison

func Exists added in v0.9.0 

func Exists(field string) Predicate

Exists creates a new Predicate using an "Exists:true" comparison

func GeoIntersects added in v0.9.0 

func GeoIntersects(field string, geoJSONer GeoJSONer) Predicate

GeoIntersects creates a new Predicate that searches geometric data that INTERSECTS a particular shape

func GeoWithin added in v0.9.0 

func GeoWithin(field string, geoJSONer GeoJSONer) Predicate

GeoWithin creates a new Predicate that searches geometric data WITHIN a particular shape

func GreaterOrEqual 

func GreaterOrEqual(field string, value any) Predicate

GreaterOrEqual creates a new Predicate using an "Greater Or Equal" comparison

func GreaterThan 

func GreaterThan(field string, value any) Predicate

GreaterThan creates a new Predicate using an "Greater Than" comparison

func In added in v0.1.1 

func In(field string, value any) Predicate

In creates a new Predicate using an "in" comparison

func InAll added in v0.8.4 

func InAll(field string, value ...any) Predicate

InAll creates a new Predicate using an "in" comparison

func LessOrEqual 

func LessOrEqual(field string, value any) Predicate

LessOrEqual creates a new Predicate using an "Less Or Equal" comparison

func LessThan 

func LessThan(field string, value any) Predicate

LessThan creates a new Predicate using an "Less Than" comparison

func New 

func New(field string, operator string, value any) Predicate

New returns a fully populated Predicate

func NotEqual 

func NotEqual(field string, value any) Predicate

NotEqual creates a new Predicate using an "Not Equals" comparison

func NotExists added in v0.9.0 

func NotExists(field string) Predicate

NotExists creates a new Predicate using an "Exists:false" comparison

func NotIn added in v0.8.4 

func NotIn(field string, value any) Predicate

NotIn creates a new Predicate using an "in" comparison

func (Predicate) And 

func (predicate Predicate) And(exp Expression) Expression

And combines this predicate with another pre-existing expression into a new And expression

func (Predicate) AndEqual 

func (predicate Predicate) AndEqual(name string, value any) Expression

AndEqual combines this predicate with another one (created from the arguments) into an AndExpression

func (Predicate) AndGreaterOrEqual 

func (predicate Predicate) AndGreaterOrEqual(name string, value any) Expression

AndGreaterOrEqual combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) AndGreaterThan 

func (predicate Predicate) AndGreaterThan(name string, value any) Expression

AndGreaterThan combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) AndIn added in v0.1.2 

func (predicate Predicate) AndIn(name string, value any) Expression

AndIn combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) AndInAll added in v0.8.4 

func (predicate Predicate) AndInAll(name string, value ...any) Expression

AndInAll combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) AndLessOrEqual 

func (predicate Predicate) AndLessOrEqual(name string, value any) Expression

AndLessOrEqual combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) AndLessThan 

func (predicate Predicate) AndLessThan(name string, value any) Expression

AndLessThan combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) AndNotEqual 

func (predicate Predicate) AndNotEqual(name string, value any) Expression

AndNotEqual combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) AndNotIn added in v0.1.2 

func (predicate Predicate) AndNotIn(name string, value any) Expression

AndNotIn combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) Fields added in v0.8.5 

func (predicate Predicate) Fields() []string

Fields is a part of the Expression interface. It returns a slice of field names that are used in this expression.

func (Predicate) IsEmpty added in v0.8.0 

func (predicate Predicate) IsEmpty() bool

IsEmpty is a part of the Expression interface. It always returns FALSE for a Predicate, since a Predicate is never empty.

func (Predicate) Match 

func (predicate Predicate) Match(fn MatcherFunc) bool

Match implements the Expression interface. It uses a MatcherFunc to determine if this predicate matches an arbitrary dataset.

func (Predicate) NotEmpty added in v0.8.0 

func (predicate Predicate) NotEmpty() bool

NotEmpty is a part of the Expression interface. It always returns TRUE for a Predicate, since a Predicate is never empty.

func (Predicate) Or 

func (predicate Predicate) Or(exp Expression) Expression

Or combines this predicate with another pre-existing expression into a new Or expression

func (Predicate) OrEqual added in v0.6.0 

func (predicate Predicate) OrEqual(name string, value any) Expression

OrEqual combines this predicate with another one (created from the arguments) into an OrExpression

func (Predicate) OrGreaterOrEqual added in v0.6.0 

func (predicate Predicate) OrGreaterOrEqual(name string, value any) Expression

OrGreaterOrEqual combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) OrGreaterThan added in v0.6.0 

func (predicate Predicate) OrGreaterThan(name string, value any) Expression

OrGreaterThan combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) OrIn added in v0.6.0 

func (predicate Predicate) OrIn(name string, value any) Expression

OrIn combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) OrInAll added in v0.8.4 

func (predicate Predicate) OrInAll(name string, value ...any) Expression

OrInAll combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) OrLessOrEqual added in v0.6.0 

func (predicate Predicate) OrLessOrEqual(name string, value any) Expression

OrLessOrEqual combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) OrLessThan added in v0.6.0 

func (predicate Predicate) OrLessThan(name string, value any) Expression

OrLessThan combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) OrNotEqual added in v0.6.0 

func (predicate Predicate) OrNotEqual(name string, value any) Expression

OrNotEqual combines this predicate with another one (created from the arguments) into an Expression

func (Predicate) OrNotIn added in v0.6.0 

func (predicate Predicate) OrNotIn(name string, value any) Expression

OrNotIn combines this predicate with another one (created from the arguments) into an Expression

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