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Lua Bit #1: Simple Templates

The following piece of code reads a template file and a table and merges them producing an output where placholders were replaced by the appropriate table elements.

local f, e = io.open(filename)
local t = dofile(conf)
 
local line
for line in f:lines() do
  line = string.gsub(line, '$%(([%w_]+)%)', function(a) return t[a] end)
  io.stdout:write(line, "\n")
end

The template file is named in filename and may look like this:

  a= $(A)
  b= $(B)
  c= 33 + $(C)

The table is read from a file named in conf, illustrated below:

return {
   A = 'aaaaa',
   B = 'bbbbb',
   C = 'ccccc'
}	

The output is sent to io.stdout, Lua standard output, and for the examples above would look like this:

  a= 'aaaaa'
  b= 'bbbbb'
  c= 33 + 'ccccc'

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