add some more ideas

Makefile

@@ -1,7 +1,7 @@
 .POSIX:
 .PHONY: all debug run clean
 DEPS=src/main.o src/util.o
-LIBS=-lgc
+LIBS=-lgc -lgmp
 DBGFLAGS=-Og -g
 DBGBIN=secd_debug
 

doc/ideas.md

@@ -18,11 +18,20 @@
   * Integers
   * Floating point numbers
   * Raw bytes
-  * Lists (cons linked list), efficient map and foldr builtin would be really nice
+  * Lists (cons linked list), efficient map, foldr, and filter instructions would be nice
   * Arrays (constant lookup continous memory)
 
 * Have methods for representing algebraic data types built into the machine.
   * Sums and products of arbitrary size, and methods for (de)constructing them.
+  * Sums as tagged pairs since the machine is untyped
+
+* Instruction for tail recursion which takes the new parameters of the stack and resets the C pointer to where it last entered a closure.
+
+* Recursion instruction which functions as dup : app
+
+* GMP arithmetic
+
+* Some sort of pattern matching facility for matching on the first element of a pair, (the constructor).
 
 # Non-Goals
 
@@ -34,8 +43,7 @@
 
 # Nicities (plausible)
 
-* Provide a compiler from a simply typed lambda calculus, coupled with a small standard library which would
-  confirm type safety of all used instructions. Maybe go even further? System F?
+* Provide a compiler from a simply typed lambda calculus, coupled with a small standard library which would confirm type safety of all used instructions. Maybe go even further? System F?
 
 * Maybe some vector operations? You could reasonably operate on chunks of the stack.
 
@@ -47,4 +55,35 @@
 
 * It's possible one might be able to JIT compile some stuff?
 
-# Ideas
+# Encoding stuff
+
+* Constant size 2 byte instructions (not including operands)
+
+* All words realistically **have** to be the same size for the stack to make sense. Which size should be used? This feels like it could easily become machine dependant.
+  * Possibly go for the highest you have, 8 bytes? Would mean that performance would be god awful on 32 bit machines. I might be ok with that? Am I?
+  * What about byte types, etc? Should we really allow that? It becomes a pain. Perhaps it is easiest to pretend computers do not exist and only deal with numbers? Only use GMP arithmetic then?
+    * Possible set of builtin types:
+      * Int64    - 64-bit signed integer
+      * Word64   - 64-bit unsigned integer
+      * Float    - 64-bit double precision floating point number
+      * Integer  - GMP
+      * Natural  - GMP
+      * Float    - GMP
+      * Rational - GMP
+      * String   - Like Data.Text
+      * Char     - 64-bit unicode codepoint.
+      * List     - Pointer to linked list
+      * Array    - Pointer to length tagged constant memory
+      * Pair     - Pointer to constant memory of length 2
+
+# File Format stuff
+
+* Much like ELF, start of with header containing basic info, reserve some bytes for future additions, have field specifing version. Then have sections.
+
+* Code section, the initial C stack.
+
+* Global section, the initial G env.
+
+* Linkable and Executable. Linkables have some sort of symbol table for wanted symbols, as well as a list of files it wishes to link with. The linker, or perhaps the VM, when loading, will then lookup these files in a global search path, perform substitution with the symbols to create an Executable file with a complete global table.
+
+* Must realise an encoding for closures, products and GMP numbers to be used in globals.