如何从 ruby 中就地编辑 ruby 文件 (Rakefile)?
How can I edit a ruby file (Rakefile) in place from within ruby?
我不确定问题标题是否有意义,但这就是我正在尝试做的事情。
我有一个包含数组的 Rakefile。我希望能够使用另一个 ruby 脚本来读取 Rakefile,向该数组添加一些内容,对其进行排序,然后将其写回到 Rakefile 中。
在伪代码中,这就是我本质上想要实现的目标:
rake_file = load file('Rakefile')
rake_file.array += 'new data'
rake_file.array.sort!
file.write Rakefile
Rakefile 包含许多数组和任务,所以我不能像对待普通文本文件一样对待它,只是将一个值附加到文件并排序,因此我的想法是加载它并像上面那样编辑数组.
这可能吗?
I can't treat it like a regular text file
然后您需要学习 ANTLR,创建 Ruby 语法,生成解析器,并编写 Java 或 C# 或 Python 树遍历器来编辑您的数组。简单:-)
我想到了一个快速简单的解决方案。该数组保存在一个文件中,比如 array_source.rb
:
a = [1, 5, 10, 15]
此文件可以手动编辑,或者,如果您需要以编程方式生成数据,则使用脚本创建,例如 create_array_source.rb :
# update the file containing the array of data in text representation
array_source_name = 'array_source.rb'
a = [1, 5, 10, 15]
# add new data
[2, 6, 11, 16].each { | e | a << e }
puts a.join(' ')
# Write it to a file
File.open(array_source_name, 'w') do | out |
# to avoid a very long single line, the data is pretty printed
groups = []
a.sort.each_slice(4) { | slice | groups << slice.join(', ') }
out.puts ' ['
out.print ' '
out.puts groups.join(",\n ")
out.puts ' ]'
end
puts "#{array_source_name} has been created"
执行:
$ ruby -w create_array_source.rb
1 5 10 15 2 6 11 16
array_source.rb has been created
文件 array_source.rb 在 :
之后 [
1, 2, 5, 6,
10, 11, 15, 16
]
在 Rakefile 中,要更新的数组位于两个特定标记之间:
task :default => [:ta, :tb] do
end
task :ta do
# $$insert array after$$
a = [1, 5, 10, 15]
# $$insert array before$$
# do something with a
end
task :tb do
# do something
end
因此很容易编写将其作为文本文件处理的脚本,将行分成两部分:
- 从开始到 "insert after" 标记
- 从"insert before"标记到结束
然后通过连接第一部分、数组和第二部分来重写文件:
# modify a specific array in a Rakefile
rakefile_name = 'Rakefile'
array_source_name = 'array_source.rb'
lines = IO.readlines(rakefile_name)
insert_marker_after_seen = false
insert_marker_before_seen = false
lines1 = []
lines2 = IO.readlines(array_source_name)
lines3 = []
# split the Rakefile
lines.each do | line |
case
when insert_marker_after_seen == false
lines1 << line
if line.include?('$$insert array after$$')
then
insert_marker_after_seen = true
end
when ! insert_marker_before_seen
# ignore array lines
if line.include?('$$insert array before$$')
then
insert_marker_before_seen = true
lines3 << line
end
else
lines3 << line
end
end
# Rewrite the Rakefile
File.open(rakefile_name, 'w') do | out |
[ lines1, lines2, lines3 ].each do | lines_group |
lines_group.each { | line | out.puts line }
end
end
puts "#{rakefile_name} has been updated with #{array_source_name}"
执行:
$ ruby -w modify_rakefile.rb
Rakefile has been updated with array_source.rb
Rakefile 之后:
task :default => [:ta, :tb] do
end
task :ta do
# $$insert array after$$
[
1, 2, 5, 6,
10, 11, 15, 16
]
# $$insert array before$$
# do something with a
end
task :tb do
# do something
end