Fixed some memory bugs.

src/ast.c

@@ -53,7 +53,20 @@ void ast_destroy(AST* ast) {
             log_dbgf("Unknown ast type %d (max: %d)", ast->type, AST_TYPE_MAX);
     }
 
-    scope_destroy_psv(ast->scope);
+    // If there're no more `AST`s linked to the scope, free.
+    if (ast->scope) {
+        log_dbgf("%p: there is scope.", ast->scope);
+        ast->scope->uses--;
+        log_dbgf(
+            "%p: were %d uses, now %d", ast->scope, ast->scope->uses + 1,
+            ast->scope->uses
+        );
+        if (!ast->scope->uses) {
+            log_dbgf("%p: no more uses, gonna free", ast->scope);
+            scope_destroy_psv(ast->scope);
+        }
+    }
+
     free(ast);
 }
 

src/exec.c

@@ -13,6 +13,9 @@ AST* exec_start(AST* ast) {
     log_dbg("Started execution.");
 
     Scope* global = scope_init(NULL);
+    global->uses = 1;
+
+    // Maybe root ast here should set global as scope?
 
     for (int i = 0; i < BUILTIN_FNS_LN; i++)
         htab_ins(
@@ -22,7 +25,10 @@ AST* exec_start(AST* ast) {
 
     log_dbg("Completed startup sequence.");
 
-    return exec_exp(ast, global);
+    AST* res = exec_exp(ast, global);
+    log_dbgf("global addr %p uses %d", global, global->uses);
+    scope_destroy_psv(global);
+    return res;
 }
 
 AST* exec_exp(AST* ast, Scope* parent) {
@@ -41,7 +47,10 @@ 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);
+    // ast->scope = scope_init(parent);
+
+    // HERE
+    exec_new_scope(ast, parent);
 
     // Loop through all but last ast.
     for (int i = 0; i < block->ln - 1; i++)
@@ -91,7 +100,11 @@ AST* exec_cf(AST* ast, size_t argc, AST** argv) {
 
 AST* exec_vdef(AST* ast, Scope* parent) {
     // Use parent's scope.
-    ast->scope = parent;
+    // ast->scope = parent;
+
+    // HERE
+    exec_inherit_scope(ast, parent);
+
     ASTVDefData* data = (ASTVDefData*)ast->data;
     AST* val = data->val;
     char* key = data->name;
@@ -101,7 +114,10 @@ AST* exec_vdef(AST* ast, Scope* parent) {
 
 AST* exec_vref(AST* ast, Scope* parent) {
     // Use parent's scope.
-    ast->scope = parent;
+    // ast->scope = parent;
+
+    // HERE
+    exec_inherit_scope(ast, parent);
     log_dbg("attempting to reference var");
     ASTVrefData* vref = (ASTVrefData*)ast->data;
 
@@ -130,3 +146,19 @@ AST* exec_fdef(AST* ast, Scope* parent) {
 }
 
 void exec_print(double n) { printf("= %lf\n", n); }
+
+inline void exec_new_scope(AST* ast, Scope* inherit) {
+    Scope* scope = scope_init(inherit);
+    ast->scope = scope;
+
+    // Update linked status.
+    scope->uses++;
+    // if (inherit) inherit->uses++;
+}
+
+inline void exec_inherit_scope(AST* ast, Scope* inherit) {
+    ast->scope = inherit;
+
+    // Update uses.
+    inherit->uses++;
+}

src/htab.c

@@ -12,8 +12,7 @@ HTab* htab_init() {
     return htab;
 }
 
-void htab_destroy(HTab* htab) { // free(htab);
-}
+void htab_destroy(HTab* htab) { free(htab); }
 
 // Get the index of a key.
 size_t geti(char* key) {

src/include/exec.h

@@ -23,4 +23,10 @@ AST* exec_fdef(AST* ast, Scope* parent);
 // Print the result of an execution.
 void exec_print(double n);
 
+// Create a new scope and mark it as linked. Also update inherited scope.
+void exec_new_scope(AST* ast, Scope* inherit);
+
+// Inherit from another scope and mark it as linked.
+void exec_inherit_scope(AST* ast, Scope* inherit);
+
 #endif

src/include/scope.h

@@ -5,8 +5,9 @@
 
 // Represents the reverse linked tree of scope.
 typedef struct SCOPE_T {
-    HTab* here;
-    struct SCOPE_T* inherit;
+    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.
 } Scope;
 
 // Create a new `Scope`. Creates new empty `HTab` for current scope.

src/scope.c

@@ -1,5 +1,7 @@
 #include "include/scope.h"
 #include "include/htab.h"
+#include "include/util.h"
+#include <stdio.h>
 #include <stdlib.h>
 
 Scope* scope_init(Scope* inherit) {
@@ -7,6 +9,9 @@ Scope* scope_init(Scope* inherit) {
 
     scope->here = htab_init();
     scope->inherit = inherit;
+    scope->uses = 0;
+
+    log_dbgf("%p: new scope, inherits from %p", scope, inherit);
 
     return scope;
 }
@@ -19,10 +24,12 @@ void scope_destroy(Scope* scope) {
 }
 
 void scope_destroy_psv(Scope* scope) {
+    log_dbgf("%p got here", scope);
     if (!scope) return;
     htab_destroy(scope->here);
     scope->inherit = NULL;
     free(scope);
+    log_dbgf("%p got here 2", scope);
 }
 
 inline void scope_add(Scope* scope, char* key, void* val) {

test/Unity

@@ -1 +1 @@
-Subproject commit cdf1d0297effc2736ee847e557b4275b4f02310b
+Subproject commit 73237c5d224169c7b4d2ec8321f9ac92e8071708