forked from GiteaTest2015/streamsql
rulego-team
112 lines
3.1 KiB
Go
112 lines
3.1 KiB
Go
/*
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* Copyright 2025 The RuleGo Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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Package condition provides condition evaluation functionality for StreamSQL.
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This package implements condition evaluation using the expr-lang library,
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supporting complex boolean expressions for filtering and conditional logic.
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It provides custom functions for SQL-like operations including LIKE pattern
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matching and NULL checking.
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# Core Features
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• Boolean Expression Evaluation - Evaluate complex boolean conditions
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• LIKE Pattern Matching - SQL-style pattern matching with % and _ wildcards
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• NULL Checking - Support for IS NULL and IS NOT NULL operations
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• Custom Functions - Extended function library for SQL compatibility
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• Type Safety - Automatic type conversion and validation
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• Performance Optimized - Compiled expressions for fast evaluation
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# Condition Interface
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Unified interface for condition evaluation:
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type Condition interface {
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Evaluate(env interface{}) bool
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}
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# Custom Functions
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Built-in SQL-compatible functions:
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// LIKE pattern matching
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like_match(text, pattern) - SQL LIKE operation with % and _ wildcards
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// NULL checking
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is_null(value) - Check if value is NULL
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is_not_null(value) - Check if value is not NULL
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# Usage Examples
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Basic condition evaluation:
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condition, err := NewExprCondition("age >= 18 AND status == 'active'")
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if err != nil {
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log.Fatal(err)
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}
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data := map[string]interface{}{
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"age": 25,
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"status": "active",
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}
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result := condition.Evaluate(data) // returns true
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LIKE pattern matching:
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condition, err := NewExprCondition("like_match(name, 'John%')")
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data := map[string]interface{}{"name": "John Smith"}
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result := condition.Evaluate(data) // returns true
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NULL checking:
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condition, err := NewExprCondition("is_not_null(email)")
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data := map[string]interface{}{"email": "user@example.com"}
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result := condition.Evaluate(data) // returns true
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Complex conditions:
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condition, err := NewExprCondition(`
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age >= 18 AND
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like_match(email, '%@company.com') AND
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is_not_null(department)
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`)
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# Pattern Matching
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LIKE pattern matching supports:
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% - Matches any sequence of characters (including empty)
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_ - Matches exactly one character
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Examples:
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'John%' matches 'John', 'John Smith', 'Johnny'
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'J_hn' matches 'John' but not 'Johan'
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'%@gmail.com' matches any email ending with @gmail.com
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# Integration
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Integrates with other StreamSQL components:
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• Stream package - Data filtering and conditional processing
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• RSQL package - WHERE and HAVING clause evaluation
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• Types package - Data type handling and conversion
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• Expr package - Expression parsing and evaluation
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*/
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package condition
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