Replace the C++ implementation with the Rust port

The Rust port (formerly gipfel-rs) is now the official successor to the
FLTK/GSL C++ code base. This squashes the port into a single commit and
removes the C++ sources (they remain in the git history below).

Layout:
  crates/gipfel-core  headless core: hills, panorama geometry, projections
                      (maxima-generated derivatives), pure-Rust LM fit,
                      gipfel: JPEG comment + EXIF I/O, profiles, stitching
  crates/gipfel-cli   command-line tools (export, info, stitch, profiles)
  crates/gipfel-app   Cosmic DE (libcosmic) GUI, binary name `gipfel`
  codegen/            maxima scripts + regen.sh for the projection code
  tests/              golden files + C++ reference harnesses (historical)

The original README is kept for now; it will be updated to describe the
Rust build. gipfel.dat, AUTHORS, ChangeLog and NEWS are unchanged.

1 files changed, 14 insertions, 0 deletions

diff --git a/codegen/fixup.py b/codegen/fixup.py
new file mode 100644
index 0000000..1131f11
--- /dev/null
+++ b/codegen/fixup.py
@@ -0,0 +1,14 @@
+#!/usr/bin/env python3
+"""Post-process maxima output for Rust:
+ - convert bare integer literals to float literals (1 -> 1.0)
+ - drop maxima noise lines (keep only 'pub fn' lines)
+"""
+import re
+import sys
+
+pat = re.compile(r"(?<![\w.])-?\d+(?![\w.])")
+
+for line in sys.stdin:
+    if not line.startswith("pub fn"):
+        continue
+    sys.stdout.write(pat.sub(lambda m: m.group(0) + ".0", line))