Execute mustache (as ruby script) in cmake execute_process - ruby

Question

I would like to use mustache as a simple templating engine in cmake for code generation.
I tried to execute it with execute_process as follow:
execute_process( COMMAND "/path/to/mustache" "<data> <template>" )
But it said its not a valid WIN32 application. And indeed, mustache is a ruby script:
#!D:/programs/Ruby23/bin/ruby.exe
#
# This file was generated by RubyGems.
#
# The application 'mustache' is installed as part of a gem, and
# this file is here to facilitate running it.
#
require 'rubygems'
version = ">= 0.a"
if ARGV.first
...
So I tried:
execute_process( COMMAMD "/path/to/ruby" "/path/to/mustache --help" )
But it don't work either... No such file or directory -- D:/programs/Ruby23/bin/mustache --help (LoadError)
How to execute a ruby script in cmake execute_process?

Answer 1

execute_process(COMMAND < cmd1 > [args1...]] ...)
Arguments must be passed as list, not as string.
# path to executables
set(RUBY_EXECUTABLE D:/programs/Ruby23/bin/ruby.exe CACHE STRING "ruby executable")
set(MUSTACHE_SCRIPT D:/programs/Ruby23/bin/mustache CACHE STRING "mustache ruby script")
# function that call mustache
function(apply_mustache data template result)
execute_process(
COMMAND ${RUBY_EXECUTABLE} -E UTF-8 ${MUSTACHE_SCRIPT} ${data} ${template}
OUTPUT_VARIABLE result_t
)
set(${result} ${result_t} PARENT_SCOPE)
endfunction()
bonus: -E UTF-8 prevent ruby to mess with utf-8 characters...