Finished garbage collector.

🎉

src/ast.c

@@ -1,7 +1,9 @@
+#include <inttypes.h>
 #include <stdio.h>
 
 #include "include/ast.h"
 #include "include/dstr.h"
+#include "include/gc.h"
 #include "include/scope.h"
 #include "include/util.h"
 
@@ -19,12 +21,19 @@ static char* asttype_names[] = {
 };
 
 AST* ast_init(ASTType type, void* data) {
-    AST* ast = malloc(sizeof(AST));
+    AST* ast = gc_alloc(sizeof(AST), GC_TYPE_AST);
 
     ast->type = type;
     ast->data = data;
     ast->scope = NULL;
 
+    if (ast->type > AST_TYPE_MAX) {
+        log_dbgf(
+            "Attempted to create invalid AST (%i > %i) to GC: ast:%p",
+            ast->type, AST_TYPE_MAX, ast
+        );
+    }
+
     return ast;
 }
 
@@ -54,15 +63,35 @@ void ast_destroy(AST* ast) {
     }
 
     // If there're no more `AST`s linked to the scope, free.
-    if (ast->scope) {
-        ast->scope->uses--;
-        if (!ast->scope->uses) { scope_destroy_psv(ast->scope); }
+    if (ast->scope && !--ast->scope->uses) scope_destroy_psv(ast->scope);
+
+    free(ast);
+}
+
+void ast_destroy_psv(AST* ast) {
+    if (!ast) return;
+
+    switch (ast->type) {
+        case AST_TYPE_NUM:   ast_num_data_destroy(ast->data); break;
+        case AST_TYPE_CALL:  ast_call_data_destroy_psv(ast->data); break;
+        case AST_TYPE_VREF:  ast_vref_data_destroy(ast->data); break;
+        case AST_TYPE_VDEF:  ast_vdef_data_destroy_psv(ast->data); break;
+        case AST_TYPE_BLOCK: ast_block_data_destroy_psv(ast->data); break;
+        case AST_TYPE_FDEF:  ast_fdef_data_destroy_psv(ast->data); break;
+        case AST_TYPE_ARG:   ast_arg_data_destroy(ast->data); break;
+        case AST_TYPE_BIF:   ast_bif_data_destroy(ast->data); break;
+        case AST_TYPE_EXC:   ast_exc_data_destroy(ast->data); break;
+        default:
+            log_dbgf("Unknown ast type %d (max: %d)", ast->type, AST_TYPE_MAX);
     }
 
     free(ast);
 }
 
-void ast_print(AST* ast) { ast_print_i(ast, 0); }
+void ast_print(AST* ast) {
+    if (!ast) return;
+    ast_print_i(ast, 0);
+}
 
 void ast_print_i(AST* ast, int i) {
     INDENT_BEGIN(i);
@@ -106,13 +135,18 @@ void ast_num_print(ASTNumData* data, int i) {
     INDENT_END;
 }
 
-ASTExcData* ast_exc_data_init(char* msg, AST* trace) {
+ASTExcData* ast_exc_data_init(const char* msg, AST* trace) {
     ASTExcData* data = malloc(sizeof(ASTExcData));
     data->msg = msg;
     data->trace = trace;
     return data;
 }
 
+void ast_exc_data_destroy(ASTExcData* exc) {
+    // `msg` is static, and `trace` will get freed in GC.
+    free(exc);
+}
+
 void ast_exc_print(ASTExcData* data, int i) {
     INDENT_BEGIN(i);
 
@@ -132,6 +166,8 @@ ASTBIFData* ast_bif_data_init(AST* fn(size_t, AST**, Scope*)) {
     return (ASTBIFData*)fn;
 }
 
+void ast_bif_data_destroy(ASTBIFData* bif) { return; }
+
 ASTCallData* ast_call_data_init(char* to, size_t argc, AST** argv) {
     talloc(ASTCallData, call);
 
@@ -152,6 +188,15 @@ void ast_call_data_destroy(ASTCallData* call) {
     free(call);
 }
 
+void ast_call_data_destroy_psv(ASTCallData* call) {
+    if (!call) return;
+    free(call->to);
+    call->to = NULL;
+    free(call->argv);
+    call->argv = NULL;
+    free(call);
+}
+
 void ast_call_print(ASTCallData* data, int i) {
     INDENT_BEGIN(i);
 
@@ -178,6 +223,11 @@ void ast_vdef_data_destroy(ASTVDefData* vdef) {
     free(vdef);
 }
 
+void ast_vdef_data_destroy_psv(ASTVDefData* vdef) {
+    free(vdef->name);
+    free(vdef);
+}
+
 void ast_vdef_print(ASTVDefData* vdef, int depth) {
     INDENT_BEGIN(depth);
 
@@ -228,6 +278,11 @@ void ast_block_data_destroy(ASTBlockData* block) {
     free(block);
 }
 
+void ast_block_data_destroy_psv(ASTBlockData* block) {
+    free(block->inside);
+    free(block);
+}
+
 void ast_block_print(ASTBlockData* data, int depth) {
     INDENT_BEGIN(depth);
 
@@ -256,6 +311,13 @@ void ast_fdef_data_destroy(ASTFDefData* fdef) {
     ast_destroy(fdef->body);
 }
 
+void ast_fdef_data_destroy_psv(ASTFDefData* fdef) {
+    free(fdef->name);
+    free(fdef->argv);
+    free(fdef->body);
+    free(fdef);
+}
+
 void ast_fdef_print(ASTFDefData* fdef, int i) {
     INDENT_BEGIN(i)
     INDENT_TITLE("ASTFDefData", fdef);

src/exec.c

@@ -13,36 +13,21 @@
 AST* exec_start(AST* ast) {
     log_dbg("Started execution.");
 
+    if (!ast) return ast;
+
     Scope* global = scope_init(NULL);
     global->uses = 1;
 
-    // Keep track of built-in function ASTs, as they arent part of the main
-    // tree.
-    // DList* builtins = dlist_init();
-
-    for (int i = 0; i < BUILTIN_FNS_LN; i++) {
-
-        // AST* builtin_ast =
-        // ast_init(AST_TYPE_BIF, ast_bif_data_init(BUILTIN_FNS[i].fn));
-
-        // dlist_append(builtins, builtin_ast);
-
+    for (int i = 0; i < BUILTIN_FNS_LN; i++)
         htab_ins(
             global->here, BUILTIN_FNS[i].name,
             ast_init(AST_TYPE_BIF, ast_bif_data_init(BUILTIN_FNS[i].fn))
         );
-    }
 
     log_dbg("Completed startup sequence.");
 
     AST* res = exec_exp(ast, global);
 
-    // Clean up built-in function ASTs.
-    /*for (int i = 0; i < builtins->ln; i++) ast_destroy(builtins->buf[i]);
-    dlist_destroy(builtins);
-    */
-
-    scope_destroy_psv(global);
     return res;
 }
 
@@ -64,10 +49,6 @@ AST* exec_exp(AST* ast, Scope* parent) {
 AST* exec_block(AST* ast, Scope* parent) {
     ASTBlockData* block = (ASTBlockData*)ast->data;
 
-    // Blocks create their own scope, shared among their expressions.
-    // ast->scope = scope_init(parent);
-
-    // HERE
     exec_new_scope(ast, parent);
 
     // Loop through all but last ast.
@@ -118,9 +99,6 @@ AST* exec_cf(AST* ast, size_t argc, AST** argv) {
 
 AST* exec_vdef(AST* ast, Scope* parent) {
     // Use parent's scope.
-    // ast->scope = parent;
-
-    // HERE
     exec_inherit_scope(ast, parent);
 
     ASTVDefData* data = (ASTVDefData*)ast->data;
@@ -132,9 +110,6 @@ AST* exec_vdef(AST* ast, Scope* parent) {
 
 AST* exec_vref(AST* ast, Scope* parent) {
     // Use parent's scope.
-    // ast->scope = parent;
-
-    // HERE
     exec_inherit_scope(ast, parent);
     log_dbg("attempting to reference var");
     ASTVrefData* vref = (ASTVrefData*)ast->data;
@@ -157,10 +132,12 @@ AST* exec_vref(AST* ast, Scope* parent) {
 AST* exec_fdef(AST* ast, Scope* parent) {
     ast->scope = scope_init(parent);
     ASTFDefData* fdef = (ASTFDefData*)ast->data;
-    AST* val = fdef->body;
+    log_dbgf("IS THIS SUSPICIOUS??? %i", fdef->body->type);
+    AST* val = ast;
     char* key = fdef->name;
     scope_add(parent, key, val);
-    return val; // Function definitions return function body.
+    // TODO: Create lambda functions.
+    return fdef->body; // Function definitions return function body.
 }
 
 void exec_print(double n) { printf("= %lf\n", n); }

src/gc.c

@@ -0,0 +1,57 @@
+#include "include/gc.h"
+#include "include/ast.h"
+#include "include/scope.h"
+#include "include/util.h"
+#include <assert.h>
+#include <stdio.h>
+
+#include <stddef.h>
+
+GC* gclist = NULL;
+
+void gc_destroy(GC* gc) { free(gc); }
+
+void f() {}
+
+void* gc_alloc(size_t sz, GCType type) {
+    assert(type <= GC_TYPE_MAX);
+
+    void* mem = malloc(sz);
+    GC* gc = malloc(sizeof(GC));
+
+    gc->p = mem;
+    gc->type = type;
+    gc->marked = false;
+    gc->nxt = gclist;
+    gclist = gc;
+
+    if (type == GC_TYPE_AST) {
+        log_dbgf("Alloc'd AST for GC: %p", mem);
+    } else if (type == GC_TYPE_SCOPE) {
+        log_dbgf("Alloc'd scope for GC: %p", mem);
+    }
+
+    return mem;
+}
+
+void gc_hack_free() {
+    while (gclist) {
+        GC* gc = gclist;
+        gclist = gclist->nxt;
+        switch (gc->type) {
+            case GC_TYPE_AST:
+                f();
+                if (((AST*)gc->p)->type > AST_TYPE_MAX) {
+                    log_dbgf(
+                        "Attempted to free invalid AST (%i > %i) to GC: gc:%p "
+                        "ast:%p",
+                        ((AST*)gc->p)->type, AST_TYPE_MAX, gc, gc->p
+                    );
+                }
+                ast_destroy_psv(gc->p);
+                break;
+            case GC_TYPE_SCOPE: scope_destroy_psv(gc->p); break;
+        }
+        gc_destroy(gc);
+    }
+}

src/grammar.y

@@ -124,7 +124,13 @@ block:
 exp:
     NUM { $$ = ast_init(AST_TYPE_NUM, ast_num_data_init($1)); }
 
-    //| BLOCKS exp BLOCKE { $$ = $2; }
+    // Function definitions.
+    | WORD GROUPS arg GROUPE EQ exp {
+        size_t argc = $3->ln;
+        AST** argv = $3->buf;
+        argarr_destroypsv($3);
+        $$ = ast_init(AST_TYPE_FDEF, ast_fdef_data_init($1, argc, argv, $6));
+    }
 
     | BLOCKS block BLOCKE {
         $$ = ast_init(AST_TYPE_BLOCK, ast_block_data_init((AST**) $2->buf, $2->ln));
@@ -193,11 +199,4 @@ exp:
         strcpy(to, "div");
         $$ = ast_init(AST_TYPE_CALL, ast_call_data_init(to, 2, argv));
     }
-
-    | WORD GROUPS arg GROUPE EQ exp {
-        size_t argc = $3->ln;
-        AST** argv = $3->buf;
-        argarr_destroypsv($3);
-        $$ = ast_init(AST_TYPE_FDEF, ast_fdef_data_init($1, argc, argv, $6));
-    }
 %%

src/htab.c

@@ -7,7 +7,9 @@
 #include <string.h>
 
 HTab* htab_init() {
-    HTab* htab = malloc(sizeof(HTab));
+    HTab* htab = calloc(1, sizeof(HTab));
+
+    log_dbgf("HTAB %p", htab);
 
     return htab;
 }
@@ -29,7 +31,6 @@ void* htab_get(HTab* htab, char* key) {
 
 void htab_ins(HTab* htab, char* key, void* data) {
     size_t i = geti(key);
-    // assert((*htab)[i] == NULL);
     (*htab)[i] = data;
     log_dbgf("Inserted something to hash table @ index %lu", i);
 }

src/include/ast.h

@@ -25,7 +25,7 @@ typedef enum {
     AST_TYPE_BLOCK, // A block of code (scope).
     AST_TYPE_FDEF,  // A function definition.
     AST_TYPE_ARG,   // A definition argument.
-    AST_TYPE_MAX = AST_TYPE_FDEF,
+    AST_TYPE_MAX = AST_TYPE_ARG,
 } ASTType;
 
 // An Abstract Syntax Tree.
@@ -41,6 +41,8 @@ AST* ast_init(ASTType type, void* data);
 AST* ast_init_scope(ASTType type, void* data, Scope* scope);
 // Destroy an `AST`, recursively.
 void ast_destroy(AST* ast);
+// Destroy an `AST`.
+void ast_destroy_psv(AST* ast);
 // Print an `AST`, recursively.
 void ast_print(AST* ast);
 // Helper function to `ast_print()`, where `i` is indentation level.
@@ -58,11 +60,11 @@ void ast_num_print(ASTNumData*, int i);
 
 // An exception.
 typedef struct ASTEXCDATA {
-    char* msg;  // The exception message.
+    const char* msg;  // The exception message.
     AST* trace; // The previous exception.
 } ASTExcData;
-// Create a new `ASTExecData.
-ASTExcData* ast_exc_data_init(char* msg, AST* trace);
+// Create a new `ASTExecData. `msg` should be static.
+ASTExcData* ast_exc_data_init(const char* msg, AST* trace);
 // Destroy an `ASTExecData`.
 void ast_exc_data_destroy(ASTExcData* exc);
 // Print an `ASTExecData`.
@@ -73,8 +75,8 @@ typedef AST* (*ASTBIFData)(size_t argc, AST** argv, Scope* scope);
 
 // Create a built-in function.
 ASTBIFData* ast_bif_data_init(AST* fn(size_t, AST**, Scope*));
-
-// There is no `ASTBIFData` destroy function, as function pointers are immortal.
+// Destroy an `ASTBIFData`.
+void ast_bif_data_destroy(ASTBIFData* bif);
 
 // A call (to a function).
 typedef struct {
@@ -85,8 +87,10 @@ typedef struct {
 
 // Create a new `ASTCallData`.
 ASTCallData* ast_call_data_init(char* to, size_t argc, AST** argv);
-// Destroy an `ASTCallData`.
+// Destroy an `ASTCallData` recursively.
 void ast_call_data_destroy(ASTCallData* call);
+// Destroy an `ASTCallData`.
+void ast_call_data_destroy_psv(ASTCallData *call);
 // Print an `ASTCallData`.
 void ast_call_print(ASTCallData*, int i);
 
@@ -100,6 +104,8 @@ typedef struct {
 ASTVDefData* ast_vdef_data_init(char* name, AST* val);
 // Destroys the `ASTVDefData`, `ASTVDefData->name`, and `ASTVDefData->val`.
 void ast_vdef_data_destroy(ASTVDefData* vdef);
+// Destroy an `ASTVDefData`.
+void ast_vdef_data_destroy_psv(ASTVDefData* vdef);
 // Print an `ASTVDefData`.
 void ast_vdef_print(ASTVDefData*, int depth);
 
@@ -125,6 +131,8 @@ typedef struct {
 ASTBlockData* ast_block_data_init(AST** inside, size_t ln);
 // Destroy an `ASTBlockData`, recursively.
 void ast_block_data_destroy(ASTBlockData* block);
+// Destroy an `ASTBlockData`.
+void ast_block_data_destroy_psv(ASTBlockData *block);
 // Print an `ASTBlockData`.
 void ast_block_print(ASTBlockData*, int i);
 
@@ -137,8 +145,10 @@ typedef struct {
 
 // Create a new `ASTFDefData`.
 ASTFDefData* ast_fdef_data_init(char* name, size_t argc, AST** argv, AST* body);
-// Destroy an `ASTFDefData`.
+// Destroy an `ASTFDefData`, recursively.
 void ast_fdef_data_destroy(ASTFDefData* fdef);
+// Destroy an `ASTFDefData`.
+void ast_fdef_data_destroy_psv(ASTFDefData* fdef);
 // Print an `ASTFDefData`.
 void ast_fdef_print(ASTFDefData* fdef, int i);
 

src/include/gc.h

@@ -0,0 +1,31 @@
+#ifndef GC_H
+#define GC_H
+
+#include <stdlib.h>
+
+// The type a GC can refer to.
+typedef enum {
+    GC_TYPE_AST,
+    GC_TYPE_SCOPE,
+    GC_TYPE_MAX = GC_TYPE_SCOPE
+} GCType;
+
+// Added to each AST and Scope; keep track of what's actually still accessible.
+typedef struct GC_STRUCT {
+    void* p;               // Pointer to the data.
+    struct GC_STRUCT* nxt; // The next GC in the linked list.
+    GCType type;           // What type of data.
+    bool marked;           // Whether the data is still accessible.
+} GC;
+
+GC* gc_init(void* p, GCType type, GC*);
+// Does not free ->p or ->nxt.
+void gc_destroy(GC* gc);
+
+// Allocate for an object in the heap, and keep track of it in the GC.
+void* gc_alloc(size_t sz, GCType type);
+
+// Free everything, immediately.
+void gc_hack_free();
+
+#endif

src/include/scope.h

@@ -7,7 +7,7 @@
 typedef struct SCOPE_T {
     HTab* here; // This scope's hash table.
     struct SCOPE_T* inherit; // The scope to inherit from.
-    int uses; // How many `AST`s are linked to this scope.
+    int uses; // How many `AST`s are linked to this scope. // TODO: REMOVE.
 } Scope;
 
 // Create a new `Scope`. Creates new empty `HTab` for current scope.

src/lexer.c

@@ -26,7 +26,7 @@ void argarr_destroy(ArgArr* argarr) {
 void argarr_destroypsv(ArgArr* argarr) { free(argarr); }
 
 void argarr_add(ArgArr* argarr, AST* arg) {
-    if ((argarr->ln + 1) * argarr->sz > argarr->sz) {
+    if ((argarr->ln + 1) * sizeof(AST*) > argarr->sz) {
         argarr->sz *= 2;
         argarr->buf = realloc(argarr->buf, argarr->sz);
         log_dbgf(

src/main.c

@@ -4,7 +4,7 @@
 #include "include/ast.h"
 #include "include/dstr.h"
 #include "include/exec.h"
-
+#include "include/gc.h"
 #include "include/lexer.h"
 #include "include/util.h"
 
@@ -22,8 +22,9 @@ int main(int argc, char** argv) {
         ast_print(root);
         AST* eval = exec_start(root);
         ast_print(eval);
-        ast_destroy(eval);
-        ast_destroy(root);
+        // ast_destroy(eval);
+        // ast_destroy(root);
+        gc_hack_free();
         exit(0);
     }
 
@@ -60,8 +61,7 @@ int main(int argc, char** argv) {
 
             AST* eval = exec_start(root);
             ast_print(eval);
-            ast_destroy(eval);
-            ast_destroy(root);
+            gc_hack_free();
         }
 
         dstr_destroy(ln);

src/scope.c

@@ -1,11 +1,12 @@
 #include "include/scope.h"
+#include "include/gc.h"
 #include "include/htab.h"
 #include "include/util.h"
 #include <stdio.h>
 #include <stdlib.h>
 
 Scope* scope_init(Scope* inherit) {
-    Scope* scope = malloc(sizeof(Scope));
+    Scope* scope = gc_alloc(sizeof(Scope), GC_TYPE_SCOPE);
 
     scope->here = htab_init();
     scope->inherit = inherit;