Change some definitions and remove thoughts.md

This commit is contained in:
Calvin Rose 2018-06-02 19:16:13 -04:00
parent 3b30b98ec0
commit b5ed4a875f
8 changed files with 15 additions and 77 deletions

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@ -39,6 +39,7 @@ Generic lisp synatx highlighting should provide good results, however.
* Proper tail calls.
* Direct interop with C via abstract types and C functions
* Dynamically load C libraries
* Functional and imperative standard library
* Lexical scoping
* Imperative Programming as well as functional
* REPL
@ -88,7 +89,7 @@ make test
### CMake
On a posix system using make as the backend, compiling and running is as follows (this is the same as
On a posix system using make as the backend, compiling and running is as follows (this is the same as
most CMake based projects).
```sh

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@ -385,5 +385,5 @@ void dst_clear_memory(void) {
}
/* Primitives for suspending GC. */
int dst_gclock() { return dst_vm_gc_suspend++; }
int dst_gclock(void) { return dst_vm_gc_suspend++; }
void dst_gcunlock(int handle) { dst_vm_gc_suspend = handle; }

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@ -39,9 +39,6 @@
#define dst_gc_unmark(m) (dst_gc_header(m)->flags &= ~DST_MEM_COLOR)
#define dst_gc_reachable(m) (dst_gc_header(m)->flags & DST_MEM_REACHABLE)
// #define dst_gclock() (dst_vm_gc_suspend++)
// #define dst_gcunlock(lock) (dst_vm_gc_suspend = lock)
/* Memory header struct. Node of a linked list of memory blocks. */
typedef struct DstGCMemoryHeader DstGCMemoryHeader;
struct DstGCMemoryHeader {

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@ -111,14 +111,14 @@ Dst dst_wrap_nil() {
return y;
}
Dst dst_wrap_true() {
Dst dst_wrap_true(void) {
Dst y;
y.type = DST_TRUE;
y.as.u64 = 0;
return y;
}
Dst dst_wrap_false() {
Dst dst_wrap_false(void) {
Dst y;
y.type = DST_FALSE;
y.as.u64 = 0;

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@ -161,7 +161,7 @@ void dst_clear_memory(void);
void dst_gcroot(Dst root);
int dst_gcunroot(Dst root);
int dst_gcunrootall(Dst root);
int dst_gclock();
int dst_gclock(void);
void dst_gcunlock(int handle);
/* Functions */

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@ -91,7 +91,10 @@ extern "C" {
#define DST_LITTLE_ENDIAN 1
#endif
/* Check compiler */
/* Define how global dst state is declared */
#ifdef DST_SINGLE_THREADED
#define DST_THREAD_LOCAL
#else
#if defined(__GNUC__)
#define DST_THREAD_LOCAL __thread
#elif defined(_MSC_BUILD)
@ -99,6 +102,7 @@ extern "C" {
#else
#define DST_THREAD_LOCAL
#endif
#endif
/* Include default headers */
#include <stdint.h>
@ -112,7 +116,7 @@ extern "C" {
__LINE__,\
__FILE__,\
(m));\
exit(-1);\
exit(1);\
} while (0)
#endif

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@ -348,11 +348,11 @@ struct Dst {
#define dst_unwrap_integer(x) ((x).as.integer)
#define dst_unwrap_real(x) ((x).as.real)
Dst dst_wrap_nil();
Dst dst_wrap_nil(void);
Dst dst_wrap_real(double x);
Dst dst_wrap_integer(int32_t x);
Dst dst_wrap_true();
Dst dst_wrap_false();
Dst dst_wrap_true(void);
Dst dst_wrap_false(void);
Dst dst_wrap_boolean(int x);
Dst dst_wrap_string(const uint8_t *x);
Dst dst_wrap_symbol(const uint8_t *x);

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@ -1,64 +0,0 @@
# Thoughts
A collection of thoughts and todo tasks for the project.
- Remove the concept of 'Ast node'. While providing fine-grained source mapping is
is reasonably useful, it complicates the implementation of macros and other source
transforming operations. Instead, we can key collection types (which have the unique
pointer property) to source mapping information in a external data structure, which is specifically
for source mapping. This data structure would be a hash table that used pointer equality
instead of value equality for entries.
The compiler would then need to keep track of 'most specific collection' node when compiling,
as the value itself would not always be a collection and contain source mapping information.
As a result, we could remove special forms like 'ast-quote', as well as ast-unwrapping logic
which potentially duplicates a fair amount of data. Macros would be easier to write without
needing to either unwrap ast values or sacrifice all source mapping.
- Serialization and deserialization of all datatypes. This would allow loading of bytecode
without needing the compiler present. However, loading C functions is currently problematic.
C functions could perhaps be wrapped in data structures that contain some meta information
about them, say home module and types. This could also allow some automated type checking for
C functions rather than writing it manually. Some slight overhead could perhaps be compensated
for by adding optional ommission of typechecking later for C functions if it can be statically
shown the types are sound.
- Better support for custom user datatypes. Tables and structs do work well for creating
custom 'objects' and records, but lack ability to differentiate between object style
values and data structure style values. For example, simply adding special keys as fields
would make plain a table or struct possibly become object-like if the write keys are added.
A Lua like solution would be metatables. It would perhaps make sense to only allow
metatables on tables, as object like behavior seems to makes most sense on mutable data (?).
For example, metatables on a struct could allow non-pure behavior unless they were extremely
limited, or purity was enforced somehow. This could break expectations of a struct to behave
as immutable data.
Also, it might make sense that the metatable of a value would actually be a struct, so
a metastruct. Implementations of Lua (LuaJIT) do not allow (or do not acknowledge)
changing certain values of a metatables after it is set, such as gc, for performance
reasons.
Currently, tables can have a prototype table, which is used to look up values recursively if they
are not found in the original table. This provides a partial solution to custom user types,
but does not have the felxibility of Lua style metatables.
- Actually make a debugger. While the VM changes to enable debugging are relatively
simple, make a useful debugger would be another project. At first, simply inspection
of the generated bytecode assembly would be a good start. Single stepping, continuation,
and inspecting the stack and current fiber would be a start.
Preferably this would be programmed in dst. The needed functionality could be exposed
in the fiber API.
Later, with information from the compiler, we could inspect variables and upvalues
by symbol. The current compiler does not do full SSA optimization, so named values
are always accessible in the stack when in scope.
- Create a pool for fibers. Whlie the general purpose allocator and GC can be made more efficient,
Fiber's can be well pooled because the allocated stack is large and can be reused. The stack
size parameter on dst_fiber could simply become the minimum memory allocated for the stack. (Do
a linear search throught the pool).
- Implement multi-methods.