matchers

Documentation

Overview

Package matchers provides pattern matching functionality for Cypher queries. It implements the MATCH clause execution by traversing the graph and finding nodes and relationships that match the specified patterns.

The matcher supports:

• Node pattern matching with labels and properties
• Relationship pattern matching with types and directions
• Path traversal through the graph
• WHERE clause filtering
• Property comparisons

Example:

matcher := matchers.NewMatcher(store, index)
rows, columns, err := matcher.ExecuteMatch(matchStmt, params)
if err != nil {
    log.Fatal(err)
}
for _, row := range rows {
    fmt.Println(row)
}

Index

• func ToFloat64(v interface{}) (float64, bool)
• func ToInt64(v interface{}) (int64, bool)
• type Matcher
  • func NewMatcher(store *storage.DB, index *graph.Index) *Matcher
  • func NewMatcherForMerge(store *storage.DB, index *graph.Index) *Matcher
  • func (m *Matcher) EvaluateExpression(path map[string]interface{}, expr ast.Expr, params map[string]interface{}) bool
  • func (m *Matcher) EvaluateExpressionWithContext(path map[string]interface{}, expr ast.Expr, params map[string]interface{}, ...) bool
  • func (m *Matcher) ExecuteMatch(stmt *ast.MatchStmt, params map[string]interface{}) (rows []map[string]interface{}, columns []string, err error)
  • func (m *Matcher) ExecuteMatchWithContext(stmt *ast.MatchStmt, params map[string]interface{}, ...) (rows []map[string]interface{}, columns []string, err error)
  • func (m *Matcher) ExecutePathForMerge(path *ast.PathExpr, params map[string]interface{}) ([]map[string]interface{}, error)
  • func (m *Matcher) ExecuteUnwind(stmt *ast.UnwindStmt, params map[string]interface{}) (rows []map[string]interface{}, columns []string, err error)
  • func (m *Matcher) ProcessReturnStmt(rows []map[string]interface{}, returnExpr *ast.ReturnExpr) ([]map[string]interface{}, []string, error)
  • func (m *Matcher) PropertyToInterface(prop graph.PropertyValue) interface{}

Functions

func ToFloat64

func ToFloat64(v interface{}) (float64, bool)

ToFloat64 converts a value to float64.

Parameters:

• v: The value to convert

Returns the float64 value and true if conversion succeeded.

Example:

if f, ok := ToFloat64(42); ok {
    fmt.Println(f) // 42.0
}

func ToInt64

func ToInt64(v interface{}) (int64, bool)

ToInt64 converts a value to int64.

Parameters:

• v: The value to convert

Returns the int64 value and true if conversion succeeded.

Example:

if i, ok := ToInt64(42.5); ok {
    fmt.Println(i) // 42
}

Types

type Matcher

type Matcher struct {
	// Store is the underlying storage database.
	Store *storage.DB

	// Index provides efficient lookups for nodes and relationships.
	Index *graph.Index
}

Matcher executes pattern matching for Cypher MATCH queries. It traverses the graph to find nodes and relationships that match the specified patterns.

func NewMatcher

func NewMatcher(store *storage.DB, index *graph.Index) *Matcher

NewMatcher creates a new Matcher instance.

Parameters:

• store: The storage database
• index: The graph index for efficient lookups

Returns a new Matcher instance.

Example:

matcher := matchers.NewMatcher(store, index)

func NewMatcherForMerge

func NewMatcherForMerge(store *storage.DB, index *graph.Index) *Matcher

NewMatcherForMerge creates a new Matcher for MERGE operations. This is an alias for NewMatcher.

Parameters:

• store: The storage database
• index: The graph index for efficient lookups

Returns a new Matcher instance.

func (*Matcher) EvaluateExpression

func (m *Matcher) EvaluateExpression(path map[string]interface{}, expr ast.Expr, params map[string]interface{}) bool

EvaluateExpression evaluates a WHERE clause expression against a path.

Parameters:

• path: The matched path containing nodes and relationships
• expr: The expression to evaluate
• params: Query parameters

Returns true if the expression evaluates to true for the given path.

func (*Matcher) EvaluateExpressionWithContext

func (m *Matcher) EvaluateExpressionWithContext(path map[string]interface{}, expr ast.Expr, params map[string]interface{}, ctxRow map[string]interface{}) bool

func (*Matcher) ExecuteMatch

func (m *Matcher) ExecuteMatch(stmt *ast.MatchStmt, params map[string]interface{}) (rows []map[string]interface{}, columns []string, err error)

ExecuteMatch executes a MATCH statement and returns the matched rows.

Parameters:

• stmt: The MATCH statement AST node
• params: Query parameters for parameterized queries

Returns the matched rows, column names, and any error encountered.

Example:

rows, columns, err := matcher.ExecuteMatch(matchStmt, map[string]interface{}{
    "name": "Alice",
})

func (*Matcher) ExecuteMatchWithContext

func (m *Matcher) ExecuteMatchWithContext(stmt *ast.MatchStmt, params map[string]interface{}, contextRows []map[string]interface{}) (rows []map[string]interface{}, columns []string, err error)

func (*Matcher) ExecutePathForMerge

func (m *Matcher) ExecutePathForMerge(path *ast.PathExpr, params map[string]interface{}) ([]map[string]interface{}, error)

func (*Matcher) ExecuteUnwind

func (m *Matcher) ExecuteUnwind(stmt *ast.UnwindStmt, params map[string]interface{}) (rows []map[string]interface{}, columns []string, err error)

func (*Matcher) ProcessReturnStmt

func (m *Matcher) ProcessReturnStmt(rows []map[string]interface{}, returnExpr *ast.ReturnExpr) ([]map[string]interface{}, []string, error)

func (*Matcher) PropertyToInterface

func (m *Matcher) PropertyToInterface(prop graph.PropertyValue) interface{}

PropertyToInterface converts a PropertyValue to a Go interface{}. Delegates to graph.PropertyValue.InterfaceValue().