Added typed defaults, print_default/print_choices and tests

[lukaswittmann]

General Changes

• Improved add_argument defaults to accept typed values via class(*) (integer, real, logical, string)
• Added per-argument help toggles:
  • print_default (default .true.): prints (default: ...) in helppage only when a default is set
  • print_choices (default .false.): optionally print choices as [choices: ...]
• Updated help formatting (goes hand in hand with the obove):
  • Defaults are shown only for arguments with explicit defaults
  • String defaults/choices are quoted ('value')
  • Choice lines are rendered on a separate line aligned to the help text column
• Switched real-value handling to working precision (real(wp)) across parsing/storage/getters to avoid precision loss in defaults/help output
• Added dual real getter support in args%get for both real and real(wp) outputs
• Better default typing: mismatched default_val types are now rejected at add_argument time and stored in parser error state
• Refined real display formatting for defaults:
  • < 1.0 -> exponential,
  • >= 1.0 -> fixed,
  • trimmed trailing zeros while keeping float-ness (.0 minimum)

Tests

• Added/updated passing unit tests for typed defaults + roundtrip, print_default/print_choices toggles, quoted string choices, help alignment, real formatting/precision (wp), dual real getter overloads, and strict mismatched-default rejection checks

Important

• Added deferred negative-tests (currently disabled via RUN_DEFERRED_FAILURE_TESTS = .false.) for error-path scenarios to enable once parse errors are returned instead of exiting: missing required args, missing values, wrong types, invalid choices, mutex violations, bound violations, unknown option/subcommand, extra positional args, removed args, and append-without-value

See issue #16 and the needed previous rework in #8 and especially #12

[Copilot]

Pull request overview

This pull request enhances the fclap command-line argument parser library with typed default values, improved help formatting, and comprehensive test coverage. The changes enable arguments to accept typed defaults (integer, real, logical, string) via polymorphic class(*) parameters, introduce print_default and print_choices toggles for help text control, and switch real-value handling to working precision (real(wp)) to avoid precision loss. The PR also adds dual real getter support for both real and real(wp) outputs, implements strict type validation for mismatched defaults, and provides refined real number display formatting.

Changes:

• Enhanced add_argument to accept typed defaults via polymorphic default_val parameter with runtime type validation
• Added print_default and print_choices boolean flags to control help text generation
• Migrated all real storage and parsing to real(wp) (working precision) with dual getter overloads for backward compatibility
• Implemented sophisticated real number formatting (exponential for |value| < 1.0, fixed for >= 1.0, with trailing zero trimming)
• Added 13 new unit tests covering typed defaults, help formatting, precision handling, and getter overloads
• Added 17 deferred failure tests (disabled by default) for error path coverage once error handling is improved

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
test/unit/main.f90	Added comprehensive tests for typed defaults, help formatting toggles, real precision, getter overloads, and deferred failure scenarios
src/fclap/fclap_parser.f90	Changed default_val from string to class(*), added type validation, integrated print_default/print_choices parameters
src/fclap/fclap_namespace.f90	Converted real storage to real(wp), added format_real_for_display and trim_real_fraction utilities, implemented dual real getters
src/fclap/fclap_formatter.f90	Added format_action_help and format_action_choices helpers to generate help text with defaults and choices
src/fclap/fclap_actions.f90	Added print_default/print_choices fields, improved error messages with with_argument_context helper, converted to real(wp)
src/fclap.f90	Exported wp (working precision kind) for public use

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[chselz]

i dont get why there is a special function for sp as wp stands for working /wanted precision and not as double precision. in accuracy.f90 it is defined as wp=dp but there one can also change it to single precision

[lukaswittmann]

For the case that a user inputs a sp default and our wp is dp (or differs)

Edit: You are right: With both get_sub_real_sp and get_sub_real_wp in the same generic, one could hit a bad case when wp equals default real kind (I dont know what would happen in such a case), but the two specifics become effectively the same interface.
I am fixing it.

Edit2: With the new API, a call like args%get(..., sp_var) will fail at compile time when wp=dp. I am unsure if this is the best solution using wp (as the core API) and having users set it to the desired kind. I have created #18 to discuss this.

[chselz]

in principle LGTM but please check comments regarding sp vs wp (per default dp but not necessarily)

[Copilot]

Pull request overview

Copilot reviewed 6 out of 7 changed files in this pull request and generated 2 comments.

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