| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package parse |
| |
| // ExprSet is a set of expressions. The map value is the expression itself; |
| // the key is the string representation of the expression, obtained via |
| // `Node#String()`. This is implemented as a map in this way to prevent |
| // duplicate expressions. |
| type ExprSet map[string]*Node |
| |
| // ExprMap is a collection of named expression sets. |
| type ExprMap map[string]ExprSet |
| |
| func NewExprSet(exprs []*Node) ExprSet { |
| if len(exprs) == 0 { |
| return nil |
| } |
| |
| es := make(ExprSet, len(exprs)) |
| es.Add(exprs) |
| return es |
| } |
| |
| // Exprs returns a slice of all expressions contained in the expression set. |
| // The resulting slice is sorted. |
| func (es ExprSet) Exprs() []*Node { |
| if len(es) == 0 { |
| return nil |
| } |
| |
| nodes := make([]*Node, 0, len(es)) |
| for _, expr := range es { |
| nodes = append(nodes, expr) |
| } |
| SortNodes(nodes) |
| return nodes |
| } |
| |
| // Add adds a set of expressions to an expression set. |
| func (es ExprSet) Add(exprs []*Node) { |
| for _, e := range exprs { |
| es[e.String()] = e |
| } |
| } |
| |
| // Disjunction ORs together all the elements in an expression set, producing a |
| // single expression. |
| func (es ExprSet) Disjunction() *Node { |
| exprs := es.Exprs() |
| |
| if len(exprs) == 0 { |
| return nil |
| } |
| |
| // Recursively OR the first expression with the rest. |
| var iter func(nodes []*Node) *Node |
| iter = func(nodes []*Node) *Node { |
| if len(nodes) == 1 { |
| return nodes[0] |
| } |
| |
| return &Node{ |
| Code: PARSE_OR, |
| Data: "||", |
| Left: nodes[0], |
| Right: iter(nodes[1:]), |
| } |
| } |
| |
| return iter(exprs) |
| } |
| |
| // Add adds a set of expressions to an expression map. |
| func (m ExprMap) Add(key string, exprs []*Node) { |
| if len(exprs) == 0 { |
| return |
| } |
| |
| // Create a new expression set if this is a new key. |
| es := m[key] |
| if es == nil { |
| es = ExprSet{} |
| m[key] = es |
| } |
| |
| es.Add(exprs) |
| } |