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BashOOP/oop.sh

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6.9 KiB

#
# BashOOP - Simple OOP implementation for bash.
# Copyright (C) 2021 Ad5001 <mail@ad5001.eu>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# This file contains all functions required to create a namespace.
# Internal variables are marked with a beginning underscore, like in most other languages.
# Signatures are a list of arguments.. Those within <> are mandatory, the ones within [] are optional.
# Namespace related variables.
_namespace=""
_namespacePath=$(realpath $(dirname ${BASH_SOURCE[0]}))
# This dictionnary saves all classes for each namespace so they can be retreived and aliased.
declare -Ag _namespacesClasses
# This dictionnary links all files for static namespaces.
declare -Ag _namespacesStaticClasses
# Namespace declaration.
# Signature: ([string namespaceName])
namespace() {
_namespace=$1;
}
# Imports a namespace into the current shell.
# It saves the path of the file so that relative paths can be
# properly resolved.
# For example, if the object Object exists within namespace Example, it
# will be accessible with "Example.Object".
# Signature: (<string namespaceFile>)
importNamespace() {
namespaceFile=$1
# Save the path in order to get the absolute path of the file.
_namespacePath=$(realpath $(dirname $namespaceFile))
. $namespaceFile
}
# Aliases the classes in global namespace.
# For example, if the object Object exists within namespace Example, it
# will be accessible with "Example.Object" and "Object".
# Signature: (<string namespaceName>)
using() {
namespaceName=$1
# Import static classes
if [ "${_namespacesStaticClasses[$namespaceName]}" != "" ]; then
oldNamespace=_namespace
namespace # Reset namespace
# Split all
staticClasses=$(echo "${_namespacesStaticClasses[$namespaceName]}" | tr ";" "\n")
for cl in $staticClasses; do
parts=$(echo "$cl" | tr ":" "\n")
static_class ${parts[0]} ${parts[1]}
done
namespace $oldNamespace
fi
# Import static classes
if [ "${_namespacesClasses[$namespaceName]}" != "" ]; then
classes=$(echo "${_namespacesClasses[$namespaceName]}" | tr ";" "\n")
for type in $classes; do
eval "$type() { $namespaceName.$type \$@; }"
done
fi
}
# Creates a "property holder" based on a name.
# A "property holder" is a dictionnary maintaining the values of properties for a specific variable.
# One is created each time an object is declared, but this function can also be used for namespaces to have global
# properties.
# Signature: (<string name>)
createPropertyHolder() {
name=$1
eval "declare -Ag _${name}_properties"
}
# Creates an object instance.
# Signature: (<string type>, <string associatedFile>, <string variableName>, [string[] constructorArguments])
_createObject() {
type=$1
associatedFile=$2
varName=$3
constructorArguments=${@:4}
# Declare dummy constructor.
eval "$varName.constructor() { :; }"
# Declare base properties.
eval "$varName.type() { echo $type; }"
eval "$varName.source() { echo $associatedFile; }"
# Create property array.
createPropertyHolder $varName
# alias the "varName" variable to itself, so that it can be used and transmitted in other variables (e.g: $varName.name would alias to varName.name)
eval "$varName='$varName'"
# Imports the file and replace all "<Type>." with the variable name.
. <(sed s/this\\./$varName./g <(sed s/$type\\./$varName./g $associatedFile))
# Call the constructor
$varName.constructor $constructorArguments
}
# Object creation.
# Signature: (<string type>, <string associatedFile>)
class() {
type=$1 # Type of the object as declared within the file.
associatedFile=$2
objFullName=$type # Type of the object referenced elsewhere
if [ "$_namespace" != "" ]; then
objFullName="${_namespace}.$type"
fi
if [ ${associatedFile::1} != "/" ]; then # Relative path, we save only the absolute path
associatedFile="$_namespacePath/$associatedFile"
fi
# Declares a new function for object initialisation.
eval "$objFullName() { _createObject $type $associatedFile \$@; }"
# Save the class in the dictionnary for reference.
if [ "$_namespace" != "" ]; then
if [ "${_namespacesClasses[$_namespace]}" == "" ]; then
_namespacesClasses[$_namespace]=$type
else
_namespacesClasses[$_namespace]="${_namespacesClasses[$_namespace]};$type"
fi
fi
}
# Static class creation
# Signature: (<string type>, <string associatedFile>)
static_class() {
type=$1 # Type of the object as declared within the file.
associatedFile=$2
objFullName=$type # Type of the object referenced elsewhere
if [ "$_namespace" != "" ]; then
objFullName="${_namespace}.$type"
fi
if [ ${associatedFile::1} != "/" ]; then # Relative path, we save only the absolute path
associatedFile="$_namespacePath/$associatedFile"
fi
# Imports the file and replace all "<Type>." with the variable name.
. <(sed s/this\\./$objFullName./g <(sed s/$type\\./$objFullName./g $associatedFile))
# Save the class in the dictionnary for reference.
if [ "$_namespace" != "" ]; then
if [ "${_namespacesStaticClasses[$_namespace]}" == "" ]; then
_namespacesStaticClasses[$_namespace]="$type:$associatedFile"
else
_namespacesStaticClasses[$_namespace]="${_namespacesStaticClasses[$_namespace]};$type:$associatedFile"
fi
fi
}
# Associated function for properties
# Signature: (<string variableName>, <string propertyName>, [string operator, string value])
_accessProperty() {
varName=$1
prop=$2
if [ "$3" == "=" ]; then
eval "_${varName}_properties[$prop]='${@:4}'"
else
eval "echo \${_${varName}_properties[$prop]}"
fi
}
# Declares a property with an optional default value.
# Signature: (<string propertyFullName>, [string propertyValue])
property() {
propertyFullName=$1
propertyValue=$2
# Split the name by ".". First element is variable name,
# second is property name.
propertyNames=($(echo $propertyFullName | tr "." "\n"))
varName=${propertyNames[0]}
prop=${propertyNames[1]}
# Default value
eval "_${varName}_properties[$prop]='$propertyValue'"
# Property alias
eval "$propertyFullName() { _accessProperty $varName $prop \$@; }"
}