Revert "Multiple rhs (#25)"

This reverts commit a1d25ae.

Author: jcupitt

CHANGELOG.md

@@ -1,11 +1,5 @@
 ## master
 
-- pattern matching rewrite
-- add multiple defs and parameter pattern match to compiler
-- add filemodel::new_from_file, rework filemodel_open
-- reloading a toolkit now deletes all defs, then does load ... adding a new
-  def to a func across a parse unit is now an error
-
 ## 9.0.14 2025/10/25
 
 - fix load cancel

TODO

@@ -1,54 +1,38 @@
-- nicholas's bug report
+- should allow vips_image ++ Image
 
-- lcomps leave stray unreffed symbols in "list unresolved"
-
-    Image_transform_item.Resize_item.Size_within_item.action.within ($SAVEDIR/start/Image.def:509)  refers to undefined symbol h
-    Image_transform_item.Resize_item.Size_within_item.action.within ($SAVEDIR/start/Image.def:509)  refers to undefined symbol w
-
-- rework pattern matching in lcomps
-
-- what does the programming window do for multiple defs?
-
-    probably need to follow next_def and concatenate them all
-
-- dir should hide $$vars
-
-- programming window is showing generated syms, like $$pattern_lhs0?
-
-- ban patterns in class parameters
-
-    or could we allow multiple class defs?
-
-        Fred (Image x) = class { ... };
-
-    probably only useful for trivial classes
-
-- what about
-
-    fred (list x) = ...;
-    fred (complex x) = ...;
-
-  ie. allow names of builtin types as well as class names
-
-  maybe:
+- remove remove prefs workspace stuff?
 
-    fred (is_list x) = ...;
+    things like max heap size should be settable ... maybe pres are useful?
 
-  ie. a predicate before the arg, as well as a class name?
+- add multiple definitions, finish function argument destructuring
 
-- do we allow eg.
+    sym has a field for "next definition", initially NULL
 
-    fred [a, b ..] = a + b;
+`   add_defining looks for an existing sym with this name, if it finds
+    one, add a new sym called "{name}-$$4" or whatever
 
-  equivalent to
+    chase to the end of "next definition" on the existing sym, append our
+    new sym
 
-    fred a:b:x = a + b;
+    during compile, generate code like
 
+        fred a b c
+            = destructured_fred, args_match
+            = fred-$$1 a b c
+        {
+            destructured_fred = rhs of fred
+            args_match = a_matches && b_matches && c_matches
+        }
 
+    if a func has many RHS and the last RHS uses destrucuring, generate a
+    final def with
 
-- remove remove prefs workspace stuff?
+        fred a b c
+            = error "no def of fred matches args a b c";
 
-    things like max heap size should be settable ... maybe pres are useful?
+    - error if more than one def of fred has no destructuring
+    - error if defs don't all have the same number of args
+    - error if a def with no destructuring isn't the last def
 
 - try < > in the image titlebar
 

meson.build

@@ -1,6 +1,6 @@
 project('nip4', 'c',
   # ie. a major after nip2 8.9 for workspace save file versioning
-  version: '9.0.15',
+  version: '9.0.14',
   license: 'GPL',
   meson_version: '>=0.64',
   default_options: [