Penlight

• Index

Contents

• Functions
• Fields

Modules

• pl
• pl.Date
• pl.List
• pl.Map
• pl.MultiMap
• pl.OrderedMap
• pl.Set
• pl.app
• pl.array2d
• pl.class
• pl.comprehension
• pl.config
• pl.data
• pl.dir
• pl.file
• pl.func
• pl.input
• pl.lapp
• pl.lexer
• pl.luabalanced
• pl.operator
• pl.path
• pl.permute
• pl.pretty
• pl.seq
• pl.sip
• pl.strict
• pl.stringio
• pl.stringx
• pl.tablex
• pl.template
• pl.test
• pl.text
• pl.utils
• pl.xml

Topics

• 01-introduction.md
• 02-arrays.md
• 03-strings.md
• 04-paths.md
• 05-dates.md
• 06-data.md
• 07-functional.md
• 08-additional.md
• 09-discussion.md

Examples

• seesubst.lua
• sipscan.lua
• symbols.lua
• test-cmp.lua
• test-data.lua
• test-listcallbacks.lua
• test-pretty.lua
• test-symbols.lua
• testapp.lua
• testclone.lua
• testconfig.lua
• testglobal.lua
• testinputfields.lua
• testinputfields2.lua
• testxml.lua
• which.lua

Module pl.lapp

Simple command-line parsing using human-readable specification.

Supports GNU-style parameters.

  lapp = require 'pl.lapp'
  local args = lapp [[
  Does some calculations
    -o,--offset (default 0.0)  Offset to add to scaled number
    -s,--scale  (number)  Scaling factor
     <number> (number )  Number to be scaled
  ]]

  print(args.offset + args.scale * args.number)

Lines begining with ‘–’ are flags; there may be a short and a long name; lines begining wih ‘’ are arguments. Anything in parens after the flag/argument is either a default, a type name or a range constraint.

>See the Guide

Dependencies: pl.sip

Functions

quit (msg, no_usage)	quit this script immediately.
error (msg, no_usage)	print an error to stderr and quit.
open (file, opt)	open a file.
assert (condn, msg)	quit if the condition is false.
add_type (name, converter, constraint)	add a new type to Lapp.
process_options_string (str, args)	process a Lapp options string.

Fields

show_usage_error

controls whether to dump usage on error.

Functions

quit (msg, no_usage)

quit this script immediately.

Parameters:

• msg: optional message
• no_usage: suppress ‘usage’ display

error (msg, no_usage)

print an error to stderr and quit.

Parameters:

• msg: a message
• no_usage: suppress ‘usage’ display

open (file, opt)

open a file. This will quit on error, and keep a list of file objects for later cleanup.

Parameters:

• file: filename
• opt: same as second parameter of io.open

assert (condn, msg)

quit if the condition is false.

Parameters:

• condn: a condition
• msg: an optional message

add_type (name, converter, constraint)

add a new type to Lapp. These appear in parens after the value like a range constraint, e.g. ‘ (integer) Process PID’

Parameters:

• name: name of type
• converter: either a function to convert values, or a Lua type name.
• constraint: optional function to verify values, should use lapp.error if failed.

process_options_string (str, args)

process a Lapp options string. Usually called as lapp().

Parameters:

• str: the options text
• args: a table of arguments (default is _G.arg)

Returns:

a table with parameter-value pairs

Fields

show_usage_error

controls whether to dump usage on error. Defaults to true