🕋 Template generator

mulle-sde has a template generator to create source files and populate new projects. But it can be useful in other scenarios. Here are three different examples:

Example: Create a serial email

Lets create a little email template. In case we only have an email address of the recipient and no other information, we will address the recipient as “Friend”:

cat <<EOF > serial-email.txt
From: me@me.com
To: <|EMAIL|>
Subject: This is a personal email

Dear <|TITLE|> <|FIRSTNAME|> <|LASTNAME:-Friend|>,

Happy holidays!

Yours
	A friend
.
EOF

If you read the previous chapter, you probably already guessed what’s coming next: we need some environment variables to fill the template.

export TITLE="Mr."
export FIRSTNAME="Joe"
export LASTNAME="Shmoe"
export EMAIL="joe.schmoe@shmoester-consult.gg"

Now we can run mulle-template -v generate serial-email.txt - to get the filled out template:

Email

To see the effect of the <|LASTNAME:-Friend|> default value, you must unset LASTNAME. An empty string still counts as value. (If you don’t like the <| |> tags, you can change them to anything, which doesn’t interfere with the other text).

Example: A boilerplate C project from templates

Let’s create a simple C project template, with a Makefile:

mkdir PROJECT_NAME

cat <<EOF > PROJECT_NAME/PROJECT_NAME.c
#include <stdio.h>


int  main( int argc, char *argv[])
{
   printf( "VfL Bochum 1848\n");
   return( 0);
}
EOF

cat <<EOF > PROJECT_NAME/Makefile
.PHONY: all

all:  <|PROJECT_NAME|>

<|PROJECT_NAME|>:  <|PROJECT_NAME|>.o

clean:
	rm <|PROJECT_NAME|> <|PROJECT_NAME|>.o  # must be TAB in front of rm
EOF

Now with the template directory in place generate the C project with mulle-template -DPROJECT_NAME=caramba generate PROJECT_NAME .. You can define environment variables on the command line as well.

C Project

Example: A script file from a template

mulle-sde ships with a number of file templates. More templates can be added with extensions (more on that later). For example mulle-sde add foo.sh creates a template generated shell script file “foo.sh” for use with mulle-bashfunctions.

Here is how “foo.sh” looks like at the time of writing (contents are subject to change with general progress):

#! /usr/bin/env mulle-bash
# shellcheck shell=bash
#
#
#  foo.sh
#  serial-letter
#
#  Copyright (c) 2022 Nat! - Mulle kybernetiK.
#  All rights reserved.
#
#
#  Redistribution and use in source and binary forms, with or without
#  modification, are permitted provided that the following conditions are met:
#
#  Redistributions of source code must retain the above copyright notice, this
#  list of conditions and the following disclaimer.
#
#  Redistributions in binary form must reproduce the above copyright notice,
#  this list of conditions and the following disclaimer in the documentation
#  and/or other materials provided with the distribution.
#
#  Neither the name of Mulle kybernetiK nor the names of its contributors
#  may be used to endorse or promote products derived from this software
#  without specific prior written permission.
#
#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
#  POSSIBILITY OF SUCH DAMAGE.
#


[ "${TRACE}" = 'YES' -o "${FOO_TRACE}" = 'YES' ] \
&& set -x  \
&& : "$0" "$@"

#
# Versioning of this script
#
MULLE_EXECUTABLE_VERSION="0.0.0"


foo::print_flags()
{
	echo "   -f    : force operation"

	##
	## ADD YOUR FLAGS DESCRIPTIONS HERE
	##

	options_technical_flags_usage \
			  "      : "
}


foo::usage()
{
	[ $# -ne 0 ] && log_error "$*"


	cat <<EOF >&2
Usage:
	foo [flags]

	##
	## ADD YOUR USAGE DESCRIPTION HERE
	##

Flags:
EOF
	foo::print_flags | LC_ALL=C sort >&2

	exit 1
}


foo::main()
{
	#
	# simple option/flag handling
	#
	local OPTION_VALUE

	while [ $# -ne 0 ]
	do
		if options_technical_flags "$1"
		then
			shift
			continue
		fi

		case "$1" in
			-f|--force)
				MULLE_FLAG_MAGNUM_FORCE='YES'
			;;

			-h*|--help|help)
				foo::usage
			;;

			--value)
				[ $# -eq 1 ] && match_list_usage "missing argument to $1"
				shift

				OPTION_VALUE="$1"
			;;

			--version)
				printf "%s\n" "${MULLE_EXECUTABLE_VERSION}"
				exit 0
			;;


			##
			## ADD YOUR FLAGS HERE
			##

			-*)
				foo::usage "Unknown flag \"$1\""
			;;

			*)
				break
			;;
		esac

		shift
	done

	options_setup_trace "${MULLE_TRACE}" && set -x

	##
	## ADD YOUR CODE HERE
	##
	log_info "Does nothing, but will soon"
}

#
# You can also use the function `call_with_flags`, which has been defined
# during mulle-boot. It lets you call 'foo::main'
# with FOO_FLAGS interposed.
#
# call_with_flags "foo::main" "${FOO_FLAGS}" "$@"

foo::main "$@"

The BSD license header on top is taken from a file ~/.config/mulle/etc/sde/header.sh, that is included by the template via a <|HEADER|> tag:

You can execute mulle-sde add anywhere. The “add” command does not require a virtual environment unlike most mulle-sde commands.

Final words

That is templating with mulle-sde. The most exciting feature is probably, the way that filenames are also subject to templating. The templating features are provided by mulle-template, which can be used outside of mulle-sde.