Argument Tools

`helpArgument`

Simple help argument handler.

Usage

helpArgument [ --only ] handlerFunction [ arguments ... ]

Simple help argument handler.

Easy --help handler for any function useful when it's the only option.

Useful for utilities which single argument types, single arguments, and no arguments (except for --help)

Oddly one of the few functions we can not offer the --help flag for. Without arguments, displays help.

Example: Example: Example: Example:

Location: bin/build/tools/argument.sh

Arguments

--only - Flag. Optional. Must be first parameter. If calling function ONLY takes the --help parameter then throw an argument error if the argument is anything but --help.
handlerFunction - Function. Required. Must be first or second parameter. If calling function ONLY takes the --help parameter then throw an argument error if the argument is anything but --help.
arguments ... - Arguments. Optional. Arguments passed to calling function to check for --help argument.

Examples

# NOT DEFINED handler
helpArgument "_${FUNCNAME[0]}" "$@" || return 0
[ "${1-}" != "--help" ] || helpArgument "_${FUNCNAME[0]}" "$@" || return 0
[ $# -eq 0 ] || helpArgument --only "_${FUNCNAME[0]}" "$@" || return "$(convertValue $? 1 0)"
# Argument 1 absolutely exists
[ "${1-}" != "--help" ] || helpArgument "_${FUNCNAME[0]}" "$@" || return 0
# DEFINED handler
local handler="_${FUNCNAME[0]}"
helpArgument "$handler" "$@" || return 0
[ "${1-}" != "--help" ] || helpArgument "$handler" "$@" || return 0
[ $# -eq 0 ] || helpArgument --only "$handler" "$@" || return "$(convertValue $? 1 0)"
# Blank Arguments for help
[ $# -gt 0 ] || helpArgument "_${FUNCNAME[0]}" --help || return 0
[ $# -gt 0 ] || helpArgument "$handler" --help || return 0

Return codes

0 - Help was not found or displayed
1 - Help was found and displayed
2 - Argument error

Requires

throwArgument - Run `handler` with an argument error (source)
bashDocumentation - Universal function documentation (source)

Common argument handling

This is a work in progress and not yet ready for release.

To handle a possible --help ending the arguments early:

# Argument: --help - Optional. Flag. This help.
# Argument: --json - Optional. Flag. Output in JSON.
# Argument: fileName - Required. FileDirectory. File to generate.
myMagic() {
    local json fileName
    stateFile=$(_arguments "${BASH_SOURCE[0]}" "${NOT-FUNCNAME[0]}" "$@") || return "$(_argumentReturn $?)"
    # shellcheck source=/dev/null
    source "$stateFile"
    # fileName set to a valid file, json is set to true or false
    # ...
}

{_arguments}

{_argumentReturn}

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