Snobol4【1】 语言实战：XML【2】 标签属性值提取【3】技巧
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 在处理字符串和文本方面具有独特的优势。本文将探讨如何使用Snobol4 语言来提取XML标签的属性值，这是一种实用的技巧，可以帮助我们更好地理解和处理XML数据。
Snobol4 简介
Snobol4 是一种字符串处理语言，它以强大的字符串操作【4】和模式匹配【5】功能而闻名。Snobol4 的语法相对简单，易于学习，但它的功能非常强大。在Snobol4 中，我们可以使用模式匹配、替换、搜索和替换等操作来处理文本。
XML 标签属性值提取的需求
在处理XML数据时，我们经常需要提取标签的属性值。例如，在HTML【6】页面中，我们可能需要提取某个元素的`class`或`id`属性值。在Snobol4 中，我们可以编写程序来自动化【7】这一过程，从而提高工作效率。
Snobol4 XML 属性值提取示例
以下是一个简单的Snobol4 程序，用于提取XML标签的属性值：
```snobol
:extract-attr
' & % ! $ @ ^ _ ` | ~
' [ ] { } ; : " ' / . ?
' t r
' x00-x1F
' x7F-x9F
' xA0-xFF
' u0100-u017F
' u0180-u024F
' u0250-u02AF
' u02B0-u02FF
' u0300-u036F
' u0370-u03FF
' u0400-u04FF
' u0500-u052F
' u0531-u0556
' u0559-u0586
' u05D0-u05FF
' u0600-u06FF
' u0700-u074F
' u0780-u07BF
' u07C0-u07FF
' u0800-u08FF
' u0900-u097F
' u0980-u09FF
' u0A00-u0A7F
' u0A80-u0AFF
' u0B00-u0B7F
' u0B80-u0BFF
' u0C00-u0C7F
' u0C80-u0CFF
' u0D00-u0D7F
' u0D80-u0DFF
' u0E00-u0E7F
' u0E80-u0EFF
' u0F00-u0FFF
' u1000-u109F
' u10A0-u10FF
' u1100-u11FF
' u1200-u12FF
' u1300-u13FF
' u1400-u14FF
' u1500-u15FF
' u1600-u16FF
' u1700-u17FF
' u1800-u18FF
' u1900-u19FF
' u1A00-u1AFF
' u1B00-u1B7F
' u1B80-u1BBF
' u1C00-u1C7F
' u1C80-u1CFF
' u1D00-u1D7F
' u1D80-u1DBF
' u1E00-u1EFF
' u1F00-u1FFF
' u2000-u206F
' u2070-u209F
' u2100-u214F
' u2150-u218F
' u2190-u21FF
' u2200-u22FF
' u2300-u23FF
' u2400-u24FF
' u2500-u257F
' u2580-u259F
' u25A0-u25FF
' u2600-u26FF
' u2700-u27BF
' u27C0-u27EF
' u27F0-u27FF
' u2800-u28FF
' u2900-u297F
' u2980-u29FF
' u2A00-u2AFF
' u2B00-u2bff
' u2C00-u2C7F
' u2C80-u2CFF
' u2D00-u2D7F
' u2D80-u2DFF
' u2E00-u2E7F
' u2E80-u2EFF
' u2F00-u2FFF
' u3000-u303F
' u3040-u309F
' u30A0-u30FF
' u3100-u312F
' u3130-u318F
' u31A0-u31FF
' u3200-u32FF
' u3300-u33FF
' u3400-u34FF
' u3500-u35FF
' u3600-u36FF
' u3700-u37FF
' u3800-u38FF
' u3900-u39FF
' u3A00-u3A7F
' u3A80-u3AFF
' u3B00-u3B7F
' u3B80-u3BBF
' u3C00-u3C7F
' u3C80-u3CFF
' u3D00-u3D7F
' u3D80-u3DBF
' u3E00-u3EFF
' u3F00-u3FFF
' u4000-u4FFF
' u5000-u527F
' u5300-u55FF
' u5600-u56FF
' u5700-u57FF
' u5900-u59FF
' u5A00-u5B7F
' u5B80-u5BBF
' u5C00-u5C7F
' u5C80-u5CFF
' u5D00-u5D7F
' u5D80-u5DBF
' u5E00-u5E7F
' u5E80-u5EFF
' u5F00-u5FFF
' u6000-u604F
' u6050-u607F
' u6080-u60FF
' u6100-u61FF
' u6200-u63FF
' u6400-u64FF
' u6500-u65FF
' u6600-u66FF
' u6700-u67FF
' u6800-u67FF
' u6900-u69FF
' u6A00-u6AFF
' u6B00-u6B7F
' u6B80-u6BBF
' u6C00-u6C7F
' u6C80-u6CFF
' u6D00-u6D7F
' u6D80-u6DBF
' u6E00-u6EFF
' u6F00-u6FFF
' u7000-u71FF
' u7200-u72FF
' u7300-u73FF
' u7400-u74FF
' u7500-u75FF
' u7600-u76FF
' u7700-u77FF
' u7800-u78FF
' u7900-u79FF
' u7A00-u7AFF
' u7B00-u7B7F
' u7B80-u7BBF
' u7C00-u7C7F
' u7C80-u7CFF
' u7D00-u7D7F
' u7D80-u7DBF
' u7E00-u7EFF
' u7F00-u7FFF
' u8000-u80FF
' u8100-u81FF
' u8200-u82FF
' u8300-u83FF
' u8400-u84FF
' u8500-u85FF
' u8600-u86FF
' u8700-u87FF
' u8800-u88FF
' u8900-u89FF
' u8A00-u8AFF
' u8B00-u8B7F
' u8B80-u8BBF
' u8C00-u8C7F
' u8C80-u8CFF
' u8D00-u8D7F
' u8D80-u8DBF
' u8E00-u8EFF
' u8F00-u8FFF
' u9000-u90FF
' u9100-u91FF
' u9200-u92FF
' u9300-u93FF
' u9400-u94FF
' u9500-u95FF
' u9600-u96FF
' u9700-u97FF
' u9800-u98FF
' u9900-u99FF
' u9A00-u9AFF
' u9B00-u9B7F
' u9B80-u9BBF
' u9C00-u9C7F
' u9C80-u9CFF
' u9D00-u9D7F
' u9D80-u9DBF
' u9E00-u9EFF
' u9F00-u9FFF
' uA000-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47F
' uA480-uA47
Comments NOTHING