Module parseopt

This module provides the standard Nim command line parser. It supports one convenience iterator over all command line options and some lower-level features.

Supported syntax:

  1. short options - -abcd, where a, b, c, d are names
  2. long option - --foo:bar, --foo=bar or --foo
  3. argument - everything else

Types

CmdLineKind = enum
  cmdEnd,                     ## end of command line reached
  cmdArgument,                ## argument detected
  cmdLongOption,              ## a long option ``--option`` detected
  cmdShortOption              ## a short option ``-c`` detected
the detected command line token   Source Edit
OptParser = object of RootObj
  cmd: string
  pos: int
  inShortState: bool
  kind*: CmdLineKind           ## the dected command line token
  key*, val*: TaintedString     ## key and value pair; ``key`` is the option
                         ## or the argument, ``value`` is not "" if
                         ## the option was given a value
  
this object implements the command line parser   Source Edit

Procs

proc initOptParser(cmdline = ""): OptParser {.
raises: [], tags: [ReadIOEffect]
.}
inits the option parser. If cmdline == "", the real command line (as provided by the OS module) is taken.   Source Edit
proc next(p: var OptParser) {.
gcsafe, extern: "npo$1", raises: [], tags: []
.}
parses the first or next option; p.kind describes what token has been parsed. p.key and p.val are set accordingly.   Source Edit
proc cmdLineRest(p: OptParser): TaintedString {.
gcsafe, extern: "npo$1", raises: [], tags: []
.}
retrieves the rest of the command line that has not been parsed yet.   Source Edit

Iterators

iterator getopt(): tuple[kind: CmdLineKind, key, val: TaintedString] {.
raises: [], tags: [ReadIOEffect]
.}
This is an convenience iterator for iterating over the command line. This uses the OptParser object. Example:
var
  filename = ""
for kind, key, val in getopt():
  case kind
  of cmdArgument:
    filename = key
  of cmdLongOption, cmdShortOption:
    case key
    of "help", "h": writeHelp()
    of "version", "v": writeVersion()
  of cmdEnd: assert(false) # cannot happen
if filename == "":
  # no filename has been given, so we show the help:
  writeHelp()
  Source Edit