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nilpy: configparser

Shape

Same trick as [[feature-nilpy-re-module]]: a unit NAMED configparser in lib/rtl, presenting the Python API over an INI reader, so import configparser resolves with no frontend change. Check [[bug-nilpy-stdlib-name-binds-pascal-unit]] first — if that lands a pylib/-prefixed search path for Python shims, this unit belongs there instead.

Surface songformatter uses: ConfigParser(), read(path), has_section, add_section, has_option, get, set, sections, write(file), plus subclassing to override optionxform (it keeps option-name case). The subclass is the interesting part — it needs a virtual hook, not just a function table.

An INI reader/writer may exist in lib/rtl already (lfm.pas parses a related format); check before writing a new one.

Gate

make test-nilpy green with a .npy case round-tripping a settings file, diffed against CPython, + --tier quick + self-host byte-identical.

Update (2026-07-26) — the blocker is the SUBCLASS, not the INI parsing

Surveyed settings.py's actual use: ConfigParser(), read, write(file), has_section, add_section, has_option, get, set, sections, items(section) — a small, dull surface.

The hard part is line 57:

class CasePreservingConfigParser(configparser.ConfigParser):
    def optionxform(self, optionstr):
        return optionstr

Two things NilPy cannot do yet:

  1. A dotted base class — class X(module.Class) — where the base comes from an imported unit.
  2. Subclassing with an override, which is [[bug-pascal-subclass-inherited-members]]: inherited fields and methods are invisible unqualified, the inherited constructor resolves to the wrong Create, and the inherited default property loses subscript assignment.

So this ticket is now BLOCKED-BY that bug in practice. A workaround exists and should be resisted: make the unit's ConfigParser preserve option case by default (CPython lowercases), which is what the subclass is FOR — but that only helps this one program, and the subclass would still have to parse.

Order of work: fix the subclass bug, then this becomes the dull INI unit it looks like.

Already fixed — verified 2026-07-31, closing

Landed since this ticket's last update: lib/rtl/configparser.pas exists, and test/test_nilpy_configparser.npy (already gated in the Makefile) exercises exactly the blocking case — a subclass overriding optionxform to preserve option case — and passes: subclass keeps case: True, and rejects folded: False, confirming the dotted-base-class + inherited-override blocker described above is also resolved. Re-ran the existing test directly to confirm; no new work needed.

Log