Re: argmatch: accept perfect matches in documented arglists

[Bruno Haible]

Hi Akim,

Sorry but I don't understand this:

> $ bison --trace=help
> bison: invalid argument ‘help’ for ‘--trace’
> Valid arguments are:
>   - ‘none        - no traces’
>   - ‘scan        - grammar scanner traces’
>   - ‘parse       - grammar parser traces’
>   - ‘parse-stats - grammar parser stats’
>   - ‘automaton   - construction of the automaton’
>   - ‘bitsets     - use of bitsets’
>   - ‘closure     - input/output of closure’
>   - ‘grammar     - reading, reducing the grammar’
>   - ‘resource    - memory consumption (where available)’
>   - ‘sets        - grammar sets: firsts, nullable etc.’
>   - ‘muscles     - m4 definitions passed to the skeleton’
>   - ‘tools       - m4 invocation’
>   - ‘m4          - m4 traces’
>   - ‘skeleton    - skeleton postprocessing’
>   - ‘time        - time consumption’
>   - ‘ielr        - IELR conversion’
>   - ‘all         - all of the above’

Why not:

$ bison --trace=help
bison: invalid argument ‘help’ for ‘--trace’
Valid arguments are:
  - ‘none’        - no traces
  - ‘scan’        - grammar scanner traces
  - ‘parse’       - grammar parser traces
  - ‘parse-stats’ - grammar parser stats
  - ‘automaton’   - construction of the automaton
  - ‘bitsets’     - use of bitsets
  - ‘closure’     - input/output of closure
  - ‘grammar’     - reading, reducing the grammar
  - ‘resource’    - memory consumption (where available)
  - ‘sets’        - grammar sets: firsts, nullable etc.
  - ‘muscles’     - m4 definitions passed to the skeleton
  - ‘tools’       - m4 invocation
  - ‘m4’          - m4 traces
  - ‘skeleton’    - skeleton postprocessing
  - ‘time’        - time consumption
  - ‘ielr’        - IELR conversion
  - ‘all’         - all of the above

> +   Accept arguments with a documentation string, such as:
> +     "foo - a first feature" -> 0
> +     "bar - a second feature" -> 1

It doesn't make sense to me to expect that the user will type
  bison --trace='none        - no traces'
when they can type
  bison --trace=none

Bruno