cypher

README

Work in progress

This project just started, it hardly works.

openCypher parser

This is a parser for openCypher. The parser follows Cypher Query Language Reference, Version 9 most the time, here are intended differences:

• Tokens are ASCII strings, however the spec allows Unicode chars. In property strings using Unicode is allowed, but not in labels, relation names, variables etc. No quoting allowed.
• Patterns supplied to CREATE may use a single parameter to specify properties, e.g: CREATE (node $paramName). This is not allowed.
• CASE parsing...

The rest is just bug, feel free to report them.

Thanks To

Alec Thomas for participle

Documentation

Index

• func Build() (*participle.Parser[Cypher], error)
• type Atom
• type ComparisonExpression
• type Create
• type Cypher
• type Debug
• type Entity
• type Expression
• type FunctionInvocation
• type Literal
• type MapLiteral
• type Match
• type MathExpression
• type Node
• type OrXorAndNotExpression
• type Path
• type ProjectionBody
• type ProjectionItem
• type ProjectionItems
• type Property
• type PropertyExpression
• type PropertyOrLabelsExpression
• type Query
• type RelationshipDetail
• type RelationshipPattern
• type Return
• type Set
• type SetItem
• type StringListNullOperatorExpression
• type Where
• type With

Functions

func Build

func Build() (*participle.Parser[Cypher], error)

Types

type Atom

type Atom struct {
	Literal   *Literal `parser:"(  @@"`
	Parameter string   `parser:"| @('$' (SymbolicName|DecimalInteger) )"`
	// CaseExpression
	// COUNT...
	// ListComprehension
	// PatternComprehension
	// ALL...
	// ANY...
	// NONE...
	// SINGLE...
	Relationship *RelationshipPattern `parser:"| @@"`
	Expression   *Expression          `parser:"| '(' @@ ')'"`
	Function     *FunctionInvocation  `parser:"| @@"`
	Variable     string               `parser:"| @SymbolicName )!"`
}

type ComparisonExpression

type ComparisonExpression struct {
	AOS1     *MathExpression `parser:"@@"`
	Relation string          `parser:"( ('=' | '<>' | '<=' | '>=' | '<' | '>')!"`
	AOS2     *MathExpression `parser:"@@ )*"`
}

type Create

type Create struct {
	Path []*Path `parser:"@@ (',' @@)*"`
}

type Cypher

type Cypher struct {
	Queries []*Query `parser:"@@*"`
}

type Debug

type Debug struct {
	Pos    lexer.Position
	EndPos lexer.Position
	Tokens []lexer.Token
}

type Entity

type Entity struct {
	Node     *Node                `parser:"'(' @@* ')'"` // @@* as empty node is valid
	Relation *RelationshipPattern `parser:"| @@"`
}

type Expression

type Expression struct {
	E *OrXorAndNotExpression `parser:"@@"`
}

type FunctionInvocation

type FunctionInvocation struct {
	// FunctionName string `parser:"( ( @(SymbolicName '.')* @SymbolicName ) | 'EXISTS' )!"`
	FunctionName string        `parser:"( ( @SymbolicName ) | 'EXISTS' )!"`
	Expression   []*Expression `parser:"'(' 'DISTINCT'? @@? (',' @@)* ')'"`
}

type Literal

type Literal struct {
	NumberLiteral  string        `parser:"  @(Float|HexInteger|OctalInteger|DecimalInteger)"`
	StringLiteral  string        `parser:"| @StringLiteral"`
	BooleanLiteral string        `parser:"| @BooleanLiteral"`
	Null           string        `parser:"| 'null'"`
	MapLiteral     []*MapLiteral `parser:"| '{' @@ (',' @@)* '}'"`
}

type MapLiteral

type MapLiteral struct {
	Key string      `parser:"@SymbolicName ':'"`
	E   *Expression `parser:"@@"`
}

type Match

type Match struct {
	Path  []*Path `parser:"@@ (',' @@)*"`
	Where *Where  `parser:"('WHERE' @@)?"`
}

type MathExpression

type MathExpression struct {
	Add   *StringListNullOperatorExpression `parser:"  '+' @@"`
	Subs  *StringListNullOperatorExpression `parser:"| '-' @@"`
	Mult  *StringListNullOperatorExpression `parser:"| '*' @@"`
	Div   *StringListNullOperatorExpression `parser:"| '/' @@"`
	Mod   *StringListNullOperatorExpression `parser:"| '%' @@"`
	Pow   *StringListNullOperatorExpression `parser:"| '^' @@"`
	SLNOE *StringListNullOperatorExpression `parser:"| @@"`
}

type Node

type Node struct {
	Variable string    `parser:"@SymbolicName?"`                       // 0 or 1 variable
	Labels   []string  `parser:"(':' @(SymbolicName|ReservedWord) )*"` // 0 or more labels
	Prop     *Property `parser:"@@?"`
}

type OrXorAndNotExpression

type OrXorAndNotExpression struct {
	OR   *ComparisonExpression `parser:"  'OR' @@"`
	XOR  *ComparisonExpression `parser:"| 'XOR' @@"`
	AND  *ComparisonExpression `parser:"| 'AND' @@"`
	NOT  *ComparisonExpression `parser:"| 'NOT' @@"`
	COMP *ComparisonExpression `parser:"| @@"`
}

type Path

type Path struct {
	Entities []*Entity `parser:"@@+"`
}

type ProjectionBody

type ProjectionBody struct {
	PIS   *ProjectionItems `parser:"'DISTINCT'? @@"`
	Skip  *Expression      `parser:"('SKIP' @@)?"`
	Limit *Expression      `parser:"('LIMIT' @@)?"`
}

type ProjectionItem

type ProjectionItem struct {
	Expression *Expression `parser:"@@"`
	AsVariable string      `parser:"('AS' @SymbolicName)?"`
}

type ProjectionItems

type ProjectionItems struct {
	PI []*ProjectionItem `parser:"('*'|@@) (',' @@)*"`
}

type Property

type Property struct {
	MapLiteral []*MapLiteral `parser:"'{' @@ (',' @@)* '}'"`
	Parameter  string        `parser:"| @('$' (SymbolicName|DecimalInteger) )"`
}

type PropertyExpression

type PropertyExpression struct {
	Atom           *Atom  `parser:"@@"`
	PropertyLookup string `parser:"('.' @(SymbolicName|ReservedWord) )+"`
}

PropertyExpression needs at least one propery

type PropertyOrLabelsExpression

type PropertyOrLabelsExpression struct {
	Atom           *Atom    `parser:"@@"`
	PropertyLookup string   `parser:"('.' @(SymbolicName|ReservedWord) )*"`
	Labels         []string `parser:"(':' @(SymbolicName|ReservedWord) )*"`
}

PropertyOrLabelsExpression can omit property

type Query

type Query struct {
	Version string  `parser:"('CYPHER' @DecimalInteger)?"`
	Create  *Create `parser:"('CREATE' @@)*"`
	Match   *Match  `parser:"('OPTIONAL'? 'MATCH' @@)*"`
	With    *With   `parser:"('WITH' @@)*"`
	Return  *Return `parser:"('RETURN' @@)*"`
	Set     *Set    `parser:"('SET' @@)*"`
}

type RelationshipDetail

type RelationshipDetail struct {
	Variable     string    `parser:"@SymbolicName?"`
	RelType      []string  `parser:"(':' @(SymbolicName|ReservedWord) )? ('|' ':'? @(SymbolicName|ReservedWord) )*"`
	RangeLiteral string    `parser:"('*' @(HexInteger|OctalInteger|DecimalInteger)? @('.' '.')? @(HexInteger|OctalInteger|DecimalInteger)* )?"`
	Prop         *Property `parser:"@@?"`
}

type RelationshipPattern

type RelationshipPattern struct {
	Pre  string              `parser:"@('<')? '-'"`
	RD   *RelationshipDetail `parser:"'[' @@? ']'"`
	Post string              `parser:"'-' @('>')?"`
}

type Return

type Return struct {
	PB *ProjectionBody `parser:"@@"`
}

type Set

type Set struct {
	Items []*SetItem `parser:"@@ (',' @@)*"`
}

type SetItem

type SetItem struct {
	Property   *PropertyExpression `parser:"( (   ( @@ '=' )"`
	Variable   string              `parser:"  | ( @SymbolicName ('='|'+=') ) )!"`
	Expression *Expression         `parser:"@@ )"`

	Variable2  string   `parser:"| ( @SymbolicName"`
	NodeLabels []string `parser:"(':' @(SymbolicName|ReservedWord) )+ )"`
}

type StringListNullOperatorExpression

type StringListNullOperatorExpression struct {
	POL *PropertyOrLabelsExpression `parser:"@@"`
}

type Where

type Where struct {
	E *Expression `parser:"@@"`
}

type With

type With struct {
	PB    *ProjectionBody `parser:"@@"`
	Where *Where          `parser:"('WHERE' @@)?"`
}