M2compiler-V3/docs/summary_stdlib-conversions.md

Step: Conversions + RealIO

Tag v3-stdlib-conversions. Suite 122/122; fixpoint OK (bootstrap/fixpoint.sh, 2,062,392 bytes).

Added

• Conversions — scalar ↔ string:
  • IntToStr(n, VAR s), CardToStr(n, VAR s) — decimal, sign for negatives, NUL-terminated (written in Modula-2).
  • RealToStr(x, VAR s) — 6 significant digits, scientific (%.6E), via the shim.
  • StrToInt(s, VAR n):BOOLEAN, StrToCard(s, VAR n):BOOLEAN — whole-string parse (optional +/-), FALSE on stray chars or empty input.
  • StrToReal(VAR s, VAR x):BOOLEAN — strtod via the shim; FALSE unless the whole string is consumed.
• RealIO — WriteReal(x) (no field), WriteRealF(x, width) (right-justified), ReadReal(VAR x) (scanf("%lf")).
• shim (runtime/syslib/shim.c) — m2realstr, m2strreal, m2writereal, m2writerealf, m2readreal; all use the existing descriptor convention (desc[0] = capacity/length, bytes follow).

Notes / deviations

• Conversions uses BOOLEAN results rather than the ISO ConvResults enumeration (V3 enumeration values in expressions are still 230). Signatures are otherwise "classic" and simple.
• WriteReal emits no leading space (consistent with WriteInt); WriteRealF(x, w) pads to w.
• The C-ABI match for the existing externals is reused (INTEGER formal ↔ C long), as in Files.

Tests

• conv_prog.mod (exit 127): IntToStr(-1234), StrToInt("42"), StrToInt("-7"), StrToInt("4x") → FALSE, StrToCard("99"), StrToReal("3.5").
• realio_prog.mod (exit 42): stdout first line 3.500000E+00, ReadReal of 1.25 from stdin.

Files

stdlib/conversions.def/.mod, stdlib/realio.def/.mod, runtime/syslib/shim.c, compiler/tests/conv_prog.mod, compiler/tests/realio_prog.mod, compiler/run_tests.sh, docs/plan.md, docs/features.md.