Snobol4 语言实战：开发日志统计系统工具
Snobol4 是一种古老的编程语言，最初在1962年由David J. Farber、Ralph E. Griswold 和 Ivan P. Polonsky 在贝尔实验室开发。尽管它已经不再流行，但Snobol4 在历史上对编程语言的发展有着重要的影响。本文将探讨如何使用Snobol4 语言开发一个简单的日志统计系统工具，以展示其独特的编程风格和解决问题的能力。
Snobol4 简介
Snobol4 是一种字符串处理语言，以其强大的模式匹配和字符串操作功能而闻名。它使用一种基于规则的语法，使得编写字符串处理程序变得非常直观。Snobol4 的程序由一系列规则组成，每个规则定义了如何处理输入字符串。
项目背景
日志统计系统是许多应用程序的重要组成部分，它能够帮助开发者了解程序的运行情况，发现潜在的错误和性能瓶颈。在这个实战中，我们将使用Snobol4 开发一个简单的日志统计工具，它可以统计日志文件中特定关键词的出现次数。
系统需求
1. 输入：日志文件路径。
2. 输出：统计结果，包括关键词出现的次数。
3. 功能：支持多个关键词的统计。
Snobol4 代码实现
以下是一个简单的Snobol4 程序，用于统计日志文件中关键词的出现次数。
```snobol
:START
'log.txt' !> FILE
'keyword1' !> KEYWORD1
'keyword2' !> KEYWORD2
'keyword3' !> KEYWORD3
0 !> COUNT1
0 !> COUNT2
0 !> COUNT3
FILE > IN
IN >>
IN > KEYWORD1
IN >>
COUNT1 +!
IN > KEYWORD2
IN >>
COUNT2 +!
IN > KEYWORD3
IN >>
COUNT3 +!
IN << FILE
FILE << COUNT1
FILE << COUNT2
FILE << COUNT3
FILE << 'END'
FILE << 'Keyword1 count: ' COUNT1
FILE << 'Keyword2 count: ' COUNT2
FILE << 'Keyword3 count: ' COUNT3
FILE << 'END'
FILE << ' '
FILE << ' '
FILE << ' '
FILE << ' '
FILE << ' '
FILE << ' '
FILE << ' '
FILE << ' '
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