spackle

Spackle is a module system for bash scripts.

Spackle will dynamically namespace imported packages, so declared variables and functions will be accessible through the package prefix specified in the imported file.

Spackle also supports package-private declarations using a two-underscore prefix (__private_varname).

Installation

First, place spackle in your project's root:

wget https://raw.githubusercontent.com/purag/spackle/master/spackle

Then, source spackle in each of your project's files:

main.sh:

#!/bin/bash
source spackle # or `source ../spackle`, `source ../../spackle`

Packages

Each project file can contain one package, which must be declared before importing any other packages. To declare a package, use the package command, which takes one argument, the package name:

test/readme/main.sh:

#!/bin/bash
source ../../spackle
package myProject

The package name must be a classic bash identifier (alphanumberic + underscores) since it will be used in identifiers.

NOTE: Like C++ namespaces, multiple files can provide the same package.

Import

You include packages by importing the files they're defined in. To do this, use the import command, which takes one argument, the path to the file:

test/readme/main.sh:

#!/bin/bash
source ../../spackle
package myProject

import util/helpers.sh

echo "$util__var" # 'a public variable'

test/readme/util/helpers.sh:

#!/bin/bash
source ../../../spackle
package util

var="a public variable"

Any public variables/functions declared in util/helpers.sh will be accessible to files that import it with the prefix util__.

Nested Imports

If you import a file which in turn imports a file, the package prefixes compound:

test/readme/main.sh:

#!/bin/bash
source ../../spackle
package myProject

import util/helpers.sh

echo "$util__var" # 'a public variable'

__trimmed=`util__str__trim "  hello  "`
echo "'$__trimmed'" # 'hello'

test/readme/util/helpers.sh:

#!/bin/bash
source ../../../spackle
package util

import string/helpers.sh

test/readme/util/string/helpers.sh

#!/bin/bash
source ../../../../spackle
package str

# trim leading and trailing whitespace from a string
trim () {
  echo "$1" | sed 's/^ *//g' | sed 's/ *$//g'
}

This example can be found in test/readme.

TODO(?)

• add a function to print a dependency tree (using set to disable execution)
• add import <file> as <renamed-package> to rename packages on the fly
• add import-private <file> to import a file privately (do not expose the imported members to anyone importing the current file)
• add import <member-list> from <file> to only import specified members