できたもの

# Render a template file
#
# $ cat template.txt
#   ==========================
#   Hello, I'm {{ name }}.
#   It's {{ wheather }} wheather today.
#   ==========================
#
# $ util::render_template template.txt 'name=bashist&wheather=good'
#   ==========================
#   Hello, I'm bashist.
#   It's good wheather today.
#   ==========================
util::render_template() {
    template_text="`cat $1`"

    saveIFS=$IFS
    IFS='=&'
    parm=($2)
    IFS=$saveIFS

    declare -A params
    for ((i=0; i<${#parm[@]}; i+=2)); do
        template_text=`echo "$template_text" | sed "s/{{ ${parm[i]} }}/${parm[i+1]}/"`
    done

    echo "$template_text"
}

テストコードはこちら。Bats便利ですね。

tree
|-- lib
|   `-- util.sh
`-- test
    |-- fixtures
    |   |-- test_include_asterisk.tpl.txt
    |   `-- test.tpl.txt
    `-- test_util.bats

test/util_test.bats

#!/usr/bin/env bats

source './lib/util.sh'

@test "util::render_template with newline" {
    expected="Hello, I'm bashist.
It's good wheather today."
    actual="`util::render_template './test/fixtures/test_include_newline.txt' 'name=bashist&wheather=good'`"
    [ "$expected" == "$actual" ]
}

@test "util::render_template with asterisk" {
    expected="Hello, bashist! Asterisk is *."
    actual="`util::render_template './test/fixtures/test_include_asterisk.txt' 'name=bashist'`"
    [ "$expected" == "$actual" ]
}

test/fixtures/test_include_newline.txt

Hello, I'm {{ name }}.
It's {{ wheather }} wheather today.

test/fixtures/test_include_asterisk.txt

Hello, {{ name }}! Asterisk is *.

うっかり、関数内で変数を " で囲むのを忘れると、* がシェルで展開されてエラーになるので、テストコードを付けておいた。

参考

Bashでテンプレートエンジンっぽいものを作った

できたもの