python基础教程2第20章 项目1：即时标记
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simple_markup.py
1 import sys, re 2 from util import * 3 4 print(‘<html><head><title>...</title><body>‘) 5 6 title = True 7 for block in blocks(sys.stdin): 8 block = re.sub(r‘*(.+?)*‘,r‘<em>1</em>‘,block) 9 if title: 10 print(‘<h1>‘) 11 print(block) 12 print(‘</h1>‘) 13 title = False 14 else: 15 print(‘<p>‘) 16 print(block) 17 print(‘</p>‘) 18 19 print(‘</body></html>‘)
handler_first.py
1 class Handler: 2 """ 3 处理从Parser调用的方法的对象。 4 5 这个解析器会在每个块的开始部分调用start()和end()方法，使用合适的块作为参数。 6 sub()方法会作用于正则表达式的替换中。当使用了‘emphasis‘这样的名字调用时，它会 7 返回合适的替换函数。 8 """ 9 def callback(self, prefix, name, *args): 10 method = getattr(self, prefix+name, None) 11 if callable(method): return method(*args)
handler.py
1 class Handler: 2 """ 3 处理从Parser调用的方法的对象。 4 5 这个解析器会在每个块的开始部分调用start()和end()方法，使适用合适的 6 块名作为参数。sub()方法会用于正则表达式替换中。当使用了‘emphasis‘ 7 这样的名字调用时，它会返回合适的替换函数。 8 """ 9 def callback(self, prefix, name, *args): 10 method = getattr(self, prefix+name, None) 11 if callable(method):return method(*args) 12 def start(self, name): 13 self.callback(‘start_‘, name) 14 def end(self, name): 15 self.callback(‘end_‘, name) 16 def sub(self, name): 17 def substitution(match): 18 result = self.callback(‘sub_‘,name, match) 19 if result is None:result= match.group(0) 20 return result 21 return substitution 22 23 class HTMLRenderer(Handler): 24 """ 25 用于生成HTML的具体处理程序 26 27 HTMLRenderer内的方法都可以通过超类处理程序的start()、 28 end()和sub()方法来访问。它们实现了用于HTML文档的基本标签。 29 """ 30 def start_document(self): 31 print(‘<html><head><title>...</title></head><body>‘) 32 def end_document(self): 33 print(‘</body></html>‘) 34 def start_paragraph(self): 35 print(‘<p>‘) 36 def end_paragraph(self): 37 print(‘</p>‘) 38 def start_heading(self): 39 print(‘<h2>‘) 40 def end_heading(self): 41 print(‘</h2>‘) 42 def start_list(self): 43 print(‘<ul>‘) 44 def end_list(self): 45 print(‘</ul>‘) 46 def start_listitem(self): 47 print(‘<li>‘) 48 def end_listitem(self): 49 print(‘</li>‘) 50 def start_title(self): 51 print(‘<h1>‘) 52 def end_title(self): 53 print(‘</h1>‘) 54 def sub_emphasis(self, match): 55 return ‘<em>%s</em>‘ % match.group(1) 56 def sub_url(self, match): 57 return ‘<a href="%s">%s</a>‘ % (match.group(1), match.group(1)) 58 def sub_email(self, match): 59 return ‘<a href="mailto:%s">%s</a>‘ % (match.group(1), match.group(1)) 60 def feed(self, data): 61 print(data)
markup.py
1 import sys, re 2 from handlers import * 3 from util import * 4 from rules import * 5 6 class Parser: 7 """ 8 语法分析器读取文本文件、应用规则并且控制处理器程序 9 """ 10 11 # 初始化成员，handler,rules(),filters() 12 def __init__(self, handler): 13 self.handler = handler 14 self.rules = [] 15 self.filters = [] 16 17 # 添加rule,方便扩展 18 def addRule(self, rule): 19 self.rules.append(rule) 20 21 # 添加过滤器， 方便扩展 22 def addFilter(self, pattern, name): 23 def filter(block, handler): 24 return re.sub(pattern, handler.sub(name), block) 25 26 self.filters.append(filter) 27 28 29 # 方法parse，读取文本（调用util.py的blocks(file)）并分成block， 30 # 使用循环用规则(rule)和过滤器（filter(block, handler)处理block， 31 def parse(self, file): 32 self.handler.start(‘document‘) 33 for block in blocks(file): 34 for filter in self.filters: 35 block = filter(block, self.handler) 36 for rule in self.rules: 37 if rule.condition(block): 38 if rule.action(block,self.handler):break 39 40 self.handler.end(‘document‘) 41 42 # Parser派生出的具体的类（通过添加具体的规则和过滤器）：用于添加HTML标记 43 44 class BasicTextParser(Parser): 45 """ 46 在构造函数中增加规则和过滤器的具体语法分析器 47 """ 48 def __init__(self, handler): 49 Parser.__init__(self, handler) 50 self.addRule(ListRule()) 51 self.addRule(ListItemRule()) 52 self.addRule(TitleRule()) 53 self.addRule(HeadingRule()) 54 self.addRule(ParagraphRule()) 55 56 self.addFilter(r‘*(.+?)*‘, ‘emphasis‘) 57 self.addFilter(r‘(http://[.a-zA-Z/]+)‘, ‘url‘) 58 self.addFilter(r‘([.a-zA-Z]+@[.a-zA-Z]+[a-zA-Z]+)‘, ‘mail‘) 59 60 # 主程序：构造handler实例，构造parser（使用对应的handler）实例,调用parser的方法parser进行对文本的处理 61 handler = HTMLRenderer() 62 parser = BasicTextParser(handler) 63 64 parser.parse(sys.stdin)
rules.py
1 class Rule: 2 """ 3 所有规则的基类 4 """ 5 6 def action(self, block, handler): 7 handler.start(self.type) 8 handler.feed(block) 9 handler.end(self.type) 10 return True 11 12 class HeadingRule(Rule): 13 """ 14 A heading is a single line that is at most 70 characters and 15 that doesn‘t end with a colon. 16 """ 17 type = ‘heading‘ 18 19 def condition(self, block): 20 return not ‘ ‘ in block and len(block) <= 70 and not block[-1] == ‘:‘ 21 22 class TitleRule(HeadingRule): 23 """ 24 The title is the first block in the document, provided that 25 it is a heading. 26 """ 27 type = ‘title‘ 28 first = True 29 30 def condition(self, block): 31 if not self.first: return False 32 self.first = False 33 return HeadingRule.condition(self, block) 34 35 class ListItemRule(Rule): 36 """ 37 A list item is a paragraph that begins with a hyphen. As part of the 38 formatting, the hyphen is removed. 39 """ 40 type = ‘listitem‘ 41 42 def condition(self, block): 43 return block[0] == ‘-‘ 44 45 def action(self, block, handler): 46 handler.start(self.type) 47 handler.feed(block[1:].strip()) 48 handler.end(self.type) 49 return True 50 51 class ListRule(ListItemRule): 52 """ 53 A list begins between a block that is not a list item and a 54 subsequent list item. It ends after the last consecutive list item. 55 """ 56 type = ‘list‘ 57 inside = False 58 59 def condition(self, block): 60 return True 61 62 def action(self, block, handler): 63 if not self.inside and ListItemRule.condition(self, block): 64 handler.start(self.type) 65 self.inside = True 66 elif self.inside and not ListItemRule.condition(self, block): 67 handler.end(self.type) 68 self.inside = False 69 return False 70 71 class ParagraphRule(Rule): 72 """ 73 A paragraph is simply a block that isn‘t covered by any of the other rules. 74 """ 75 type = ‘paragraph‘ 76 77 def condition(self, block): 78 return True
util.py
1 def lines(file): 2 # 将文件打包成行生成器，只是在文件的最后一行添加一个空行 3 for line in file:yield line 4 yield ‘ ‘ 5 6 def blocks(file): 7 block=[] 8 for line in lines(file): 9 #搜集所有的行，返回一个字符串 10 if line.strip(): 11 block.append(line) 12 #遇到空格，然后返回所有的行，也不会搜集空行 13 elif block: #如果不判断就会将初始化的空行返回，遇到空行结束搜集，如果文件尾没有空行，则不会结束。 14 yield ‘‘.join(block).strip() 15 block=[]#新生成一个空列表，继续以上的步骤
test_input.py
1 Welcome to World Wide Spam, Inc. 2 3 These are the corporate web pages of *World Wide Spam*, Inc. We hope 4 you find your stay enjoyable, and that you will sample many of our 5 products. 6 7 A short history of the company 8 9 World Wide Spam was started in the summer of 2000. The business 10 concept was to ride the dot-com wave and to make money both through 11 bulk email and by selling canned meat online. 12 13 After receiving several complaints from customers who weren‘t 14 satisfied by their bulk email, World Wide Spam altered their profile, 15 and focused 100% on canned goods. Today, they rank as the world‘s 16 13,892nd online supplier of SPAM. 17 18 Destinations 19 20 From this page you may visit several of our interesting web pages: 21 22 - What is SPAM? (http://wwspam.fu/whatisspam) 23 24 - How do they make it? (http://wwspam.fu/howtomakeit) 25 26 - Why should I eat it? (http://wwspam.fu/whyeatit) 27 28 How to get in touch with us 29 30 You can get in touch with us in *many* ways: By phone(555-1234), by 31 email (wwspam@wwspam.fu) or by visiting our customer feedback page 32 (http://wwspam.fu/feedback).
test_output.py
1 <html><head><title>...</title></head><body> 2 <h1> 3 Welcome to World Wide Spam, Inc. 4 </h1> 5 <p> 6 These are the corporate web pages of <em>World Wide Spam</em>, Inc. We hope 7 you find your stay enjoyable, and that you will sample many of our 8 products. 9 </p> 10 <h2> 11 A short history of the company 12 </h2> 13 <p> 14 World Wide Spam was started in the summer of 2000. The business 15 concept was to ride the dot-com wave and to make money both through 16 bulk email and by selling canned meat online. 17 </p> 18 <p> 19 After receiving several complaints from customers who weren‘t 20 satisfied by their bulk email, World Wide Spam altered their profile, 21 and focused 100% on canned goods. Today, they rank as the world‘s 22 13,892nd online supplier of SPAM. 23 </p> 24 <h2> 25 Destinations 26 </h2> 27 <p> 28 From this page you may visit several of our interesting web pages: 29 </p> 30 <ul> 31 <li> 32 What is SPAM? (<a href="http://wwspam.fu/whatisspam">http://wwspam.fu/whatisspam</a>) 33 </li> 34 <li> 35 How do they make it? (<a href="http://wwspam.fu/howtomakeit">http://wwspam.fu/howtomakeit</a>) 36 </li> 37 <li> 38 Why should I eat it? (<a href="http://wwspam.fu/whyeatit">http://wwspam.fu/whyeatit</a>) 39 </li> 40 </ul> 41 <h2> 42 How to get in touch with us 43 </h2> 44 <p> 45 You can get in touch with us in <em>many</em> ways: By phone(555-1234), by 46 email (wwspam@wwspam.fu) or by visiting our customer feedback page 47 (<a href="http://wwspam.fu/feedback">http://wwspam.fu/feedback</a>). 48 </p> 49 </body></html>
readme.txt
1 20.1 问题是什么 2 将文本由程序自动转成HTML 3 4 要做的工作基本上就是首先将各种文本元素进行分类，比如标题和被强调的文本，然后清晰地标记出它们。为此， 5 要将HTML标记添加到文本中，使文档能在浏览器中作为网页显示并使用。 6 7 编写原型 8 9 定义目标 10 11 输入不应该包含人工代码或者标签 12 应该可以处理不同的块 13 20.2 有用的工具 14 要对文件能读写，或者至少能从标准输入（sys.stdin）中读写，在print输出 15 需要对所输入的行进行迭代 16 需要使用一些字符串方法 17 需要一个或者两个生成器 18 可能需要用到re模块 19 20.3 准备工作 20 测试套件评估进度 test_input.txt 21 20.4 初次实现 22 首先要做的是本文本切成段落，段落被一个或者多个空行隔开。比段落更准确的是块（block） 23 20.4.1 找出文本块 24 找出块的简单方法就是搜集遇到的行，直到遇到一个空行，然后返回已经收集到的行。那些返回的行就是一个块。 25 if 。。elif的逻辑选择， 26 20.5.2 添加一些标记 27 28 总结: 29 主程序（markup.py） 30 1、将处理过程封装为方法parse，这个整个程序的处理过程 31 2、将规则条件抽象成规则类，避免了大量if语句使用。 32 3、self.addRule增加规则对象。利用规则对象的方法和属性实际操作块的处理。 33 4、生成一个html处理器对象（HTMLRenderer），传给BasicTextParser生成对象parser，改该对象调用rule对象接受handler 34 对象处理block 35 5、最重要的是如何将功能抽象成具体的类，以及各个类所有的功能，高内聚低耦合。
fun_study.py
1 # def count(): 2 # ‘‘‘ 3 # 创建以一个空列表，每次讲定义的函数名存入列表，函数执行三次，列表值[f,f,f] 4 # 第三次时i为3，fi（）=f(),这是f同样保存了，第三次时的父函数的作用域i=3 5 # 所以f1=3*3=9 6 # ‘‘‘ 7 # fs = [] 8 # for i in range(1, 4): 9 # def f(): 10 # return i*i 11 # fs.append(f) 12 # print(i) 13 # return fs 14 15 16 def count(): 17 def f(j): 18 def g(): 19 return j*j 20 return g 21 fs = [] 22 for i in range(1, 4): 23 fs.append(f(i)) 24 return fs 25 ‘‘‘体现闭包的用法。fs中函数对象将f(1),f(2),f(3)作用域存放在函数中‘‘‘ 26 f1,f2,f3=count() 27 print(f1()) 28 print(f2()) 29 print(f3())
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