Multiple rhs (#24)

* notes

* more hacking

* more hacking

* more argh

* hackikng away

* stuff

* start rewriting all pattern matching

* pattern match rewrite almost done

* pattern match rewrite passes the first test

* codegen for multiple rhs passes first test

* note another bug

* note codegen after parse unit

* getting closer

* next multidef example works

* make later defs local to main def

to avoid top level mutual recursion

* multiple defs test case three works

* add some tests

* detect redefinition across parse units

* case three works

* fix up filemodel merge

* fix access to nested structs

* more debugging

* omg fixed pattern defs

* more fixes

* fix local multiple defs

* tiny

* fix Vector ++ Image

* fix Image op Vector

* add more tests for multiple RHS

* ready for 9.0.14 release

* fix date

Author: jcupitt

CHANGELOG.md

@@ -1,5 +1,11 @@
 ## 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

@@ -1,8 +1,4 @@
-- should allow vips_image ++ Image
-
-- remove remove prefs workspace stuff?
-
-    things like max heap size should be settable ... maybe pres are useful?
+- nicholas's bug report
 
 - lcomps leave stray unreffed symbols in "list unresolved"
 
@@ -17,6 +13,39 @@
 
 - dir should hide $$vars
 
+- programming window is showing generated syms, like $$pattern_lhs0?
+
+- ban patterns in class parameters
+
+    or could we allow multiple class defs?
+
+        Fred (Image x) = class { ... };
+
+    probably only useful for trivial classes
+
+- what about
+
+    fred (list x) = ...;
+    fred (complex x) = ...;
+
+  ie. allow names of builtin types as well as class names
+
+  maybe:
+
+    fred (is_list x) = ...;
+
+  ie. a predicate before the arg, as well as a class name?
+
+- do we allow eg.
+
+    fred [a, b ..] = a + b;
+
+  equivalent to
+
+    fred a:b:x = a + b;
+
+
+
 - programming window is showing generated syms, like $$pattern_lhs0?
 
 - ban patterns in class parameters