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This is the readme file of the Lua Template Engine

Overview

A Lua module for the evaluation of textual templates, for example to support code generation.

Using a special syntax, templates can refer to any valid Lua expression which must be defined in the environment passed to the evaluation function. Arbitrary Lua code can also be intertwined with the text.

Below is a representative example. For more simple examples, please see src/sample/sample.lua.

local tpleval = require('template-text').template_eval

local tpl = [[
Hi! This is a text template!
It can reference any symbol which is defined in the environment (i.e. a table)
given to the evaluation function:

Hello $(name) for $(many(5)) times!

Actual Lua code can be used in the template, starting the line with a '@':
@ for k,v in pairs( aTable ) do
key: $(k)    value: $(v)
@ end
]]

local dummyF = function(i) return i*3 end
local dummyT = {"bear", "wolf", "shark", "monkey"}

local ok, text = tpleval(tpl,
  { name   = "Marco",
    many   = dummyF,
    aTable = dummyT}
)
if not ok then
  print("ERROR: " .. text) -- in this case text would be an error message
else
  print(text)
end

Running this sample with

cd src/sample
lua fromreadme.lua

should produce the following output:

Hi! This is a text template!
It can reference any symbol which is defined in the environment (i.e. a table)
given to the evaluation function:

Hello Marco for 15 times!

Actual Lua code can be used in the template, starting the line with a '@':
key: 1    value: bear
key: 2    value: wolf
key: 3    value: shark
key: 4    value: monkey

Installing

Via LuaRocks

If you can use LuaRocks, then this command will install the package from the public repository:

luarocks install --local template-text

Alternatively, you can install from a local clone of the source repository:

git clone https://github.com/mfrigerio17/lua-template-engine.git
cd lua-template-engine/
luarocks --local make           # installs the module locally
eval `luarocks path`            # need this everytime, with --local
lua src/sample/fromreadme.lua   # try a sample

Avoid the --local switch to install the module in a system-wide Lua directory.

Manual installation

You may simply copy the source file template-text.lua in a system-wide Lua directory.

git clone https://github.com/mfrigerio17/lua-template-engine.git
cd lua-template-engine/

# This one will need root privileges
mkdir -p /usr/local/share/lua/5.2/ && cp src/template-text.lua /usr/local/share/lua/5.2/

# Run a sample
lua src/sample/fromreadme.lua

Installing LuaRocks

See the official website.

Beware that the package-manger version of LuaRocks might default to Lua 5.1. Install it manually with something like the following (replace apt with your package manager, and run the install commands with root privileges):

apt install make wget unzip   # required later
apt install liblua5.2-dev     # also required, by LuaRocks
wget https://luarocks.org/releases/luarocks-3.3.1.tar.gz
tar zxpf luarocks-3.3.1.tar.gz
cd luarocks-3.3.1
./configure --lua-version=5.2
make && make install

Dependencies

The template engine does not depend on any other module. Lua > 5.1 is required.

Authorship

By Marco Frigerio, heavily based on the code available in the Lua-users-wiki

Copyright © 2020-2021 Marco Frigerio
All rights reserved.

Released under a permissive BSD license. See the LICENSE file for details.